Remifentanil Hameln
Ultra-short-acting synthetic opioid analgesic for anesthesia and intensive care sedation
Remifentanil Hameln is an ultra-short-acting synthetic opioid analgesic used exclusively in hospital settings during general anesthesia and in intensive care. Unlike most opioids, its duration of action is measured in minutes rather than hours because it is rapidly broken down by non-specific esterases in the blood and tissues. This gives remifentanil a unique context-sensitive half-life of approximately 3–4 minutes that remains constant no matter how long it has been infused, allowing anesthesiologists to precisely titrate analgesia and achieve rapid recovery. It must only be administered intravenously by or under the direct supervision of a qualified anesthesiologist with immediate access to airway management and resuscitation equipment.
Quick Facts
Key Takeaways
- Remifentanil Hameln is an ultra-short-acting mu-opioid receptor agonist used only in hospital settings for analgesia during general anesthesia, for sedation of mechanically ventilated intensive care patients, and for analgesia during conscious procedures.
- Its distinctive pharmacokinetic profile comes from rapid hydrolysis by non-specific blood and tissue esterases, giving a predictable offset of action within minutes and making it suitable for patients with severe liver or kidney impairment.
- Because remifentanil produces no meaningful residual analgesia, longer-acting pain relief must be given before the infusion is discontinued to avoid acute postoperative pain and opioid-induced hyperalgesia.
- Remifentanil must never be given by the epidural or intrathecal route because the glycine excipient is potentially neurotoxic when injected near the central nervous system.
- Dose-dependent respiratory depression, muscle rigidity, bradycardia, and hypotension are predictable effects that require continuous monitoring and immediate access to airway support and naloxone.
What Is Remifentanil Hameln and What Is It Used For?
Quick Answer: Remifentanil Hameln is an ultra-short-acting synthetic opioid analgesic belonging to the phenylpiperidine class. It is used intravenously in hospital settings to provide pain relief during the induction and maintenance of general anesthesia, to sedate mechanically ventilated adults in intensive care, and to provide analgesia for conscious surgical procedures.
Remifentanil is a pharmacologically unique member of the opioid analgesic family. Developed in the early 1990s and introduced to clinical practice in 1996, it was designed to combine the potent analgesic effect of fentanyl-type opioids with a metabolic profile that allows rapid offset of action. Its chemical structure incorporates an ester linkage that renders it susceptible to rapid hydrolysis by non-specific esterases present in blood and tissues throughout the body. This distinguishes remifentanil from virtually every other opioid in clinical use and gives it pharmacokinetic properties that make it especially well suited for continuous intravenous infusion during anesthesia.
Like other mu-opioid receptor agonists, remifentanil produces dose-dependent analgesia, sedation, and respiratory depression by binding to mu-opioid receptors in the central nervous system. On a weight-for-weight basis its potency is broadly similar to fentanyl, but because it is measured as free base and its duration of action is so short, clinical dosing is typically expressed as an infusion rate in micrograms per kilogram per minute rather than as bolus doses. The drug has a very rapid onset of action, with clinical effects appearing within about one minute of intravenous administration, and an equally rapid offset once administration is stopped.
Remifentanil Hameln is supplied as a sterile white to off-white lyophilised powder that must be reconstituted and further diluted before intravenous administration. Vials are available in three strengths containing 1 mg, 2 mg, or 5 mg of remifentanil (as the hydrochloride salt). Once reconstituted and diluted, the solution is given as either an intravenous bolus injection during induction or, more commonly, as a continuous intravenous infusion titrated to the individual patient’s response and the level of surgical stimulation.
Induction and Maintenance of General Anesthesia in Adults
The principal clinical use of Remifentanil Hameln in adults is the provision of analgesia during the induction and maintenance of general anesthesia. It is used as part of a balanced anesthetic technique in combination with hypnotic agents such as propofol, thiopental, or isoflurane. Its rapid onset allows anesthesiologists to anticipate and blunt the sympathetic response to painful surgical stimuli such as skin incision, intubation, or bone manipulation. Because the depth of analgesia can be adjusted almost immediately by changing the infusion rate, remifentanil is especially useful in procedures where the intensity of noxious stimulation varies rapidly, such as cardiothoracic, neurosurgical, and major vascular operations.
Intensive Care Sedation in Adults
Remifentanil Hameln is approved for the provision of analgesia and sedation in mechanically ventilated intensive care patients aged 18 years and older. It can be used for continuous infusions of up to 3 days. The rapid offset of effect is particularly advantageous in critically ill patients because it allows reliable and quick neurological assessment (the “sedation holiday”), smooth weaning from the ventilator, and fast extubation once sedation is discontinued. Remifentanil’s organ-independent metabolism also makes it attractive for patients with failing liver or kidney function, in whom other opioids can accumulate unpredictably.
Analgesia During Conscious Procedures
Outside the operating theatre, Remifentanil Hameln is used to provide analgesia in awake or lightly sedated patients undergoing painful procedures such as shockwave lithotripsy, awake fibreoptic intubation, colonoscopy, or interventional radiology. In these settings the drug is typically titrated to maintain spontaneous ventilation while providing profound analgesia. Because even small errors in dose can cause apnea, such procedures must be performed by practitioners experienced in airway management and with resuscitation equipment immediately to hand.
Use in Children
Remifentanil Hameln is approved for intravenous use in children aged 1 year and older for the maintenance of general anesthesia. It is not recommended for induction of anesthesia in children because there are insufficient clinical data supporting this use in the pediatric population. Safety and efficacy in children younger than 1 year have not been established, and remifentanil is not approved for use in neonates or infants under 12 months of age. In all pediatric use, the dose is calculated carefully by body weight and the infusion titrated by an anesthesiologist experienced in children.
Remifentanil Hameln is administered only by specialist physicians (typically anesthesiologists or intensive care physicians) in hospital operating theatres, recovery areas, and intensive care units equipped with continuous respiratory and cardiovascular monitoring, airway management equipment, and immediate access to opioid antagonists. It is never dispensed for self-administration at home.
What Should You Know Before Taking Remifentanil Hameln?
Quick Answer: Remifentanil Hameln must not be used by epidural or intrathecal routes, in patients with known hypersensitivity to fentanyl analogues, or as the sole agent for induction of anesthesia. Special caution is required in patients with significant respiratory disease, cardiovascular instability, hypovolemia, or those taking MAO inhibitors. The drug is not appropriate for unsupervised outpatient use.
Because remifentanil is administered exclusively in monitored hospital environments, the preoperative assessment is usually carried out by the anesthesiologist who will administer the drug. This assessment includes a review of past medical history, current medications, allergies, previous experience with anesthesia or surgery, and a focused examination of the airway, respiratory, and cardiovascular systems. Understanding the contraindications and precautions associated with remifentanil is essential for safe perioperative care.
Contraindications
Remifentanil Hameln must not be used in any of the following circumstances:
- Hypersensitivity to remifentanil, other fentanyl analogues (fentanyl, alfentanil, sufentanil), or to any of the excipients (glycine and hydrochloric acid).
- Epidural or intrathecal administration — remifentanil must never be injected into the epidural space, the subarachnoid space, or elsewhere in the neuraxis because the glycine excipient is potentially neurotoxic in this environment.
- Use as the sole anesthetic agent for induction of anesthesia — remifentanil does not reliably produce loss of consciousness and must be combined with a hypnotic induction agent.
Warnings and Precautions
Inform your anesthesiologist before receiving Remifentanil Hameln if you have any of the following conditions or circumstances, as they may require dose adjustment, extended monitoring, or additional precautions:
- Existing respiratory disease, including asthma, chronic obstructive pulmonary disease (COPD), or obstructive sleep apnea
- Known cardiovascular disease, including coronary artery disease, arrhythmias, or heart failure
- Current treatment with beta-blockers, calcium channel blockers, or other drugs that affect heart rate or blood pressure
- Hypovolemia (reduced circulating blood volume) from bleeding, dehydration, or other causes
- Raised intracranial pressure or significant head injury
- Severe obesity, in whom dose calculation should normally be based on ideal body weight
- Mental health conditions including severe depression or current substance use disorder
- A personal or family history of opioid misuse or dependence
- Chronic treatment with other strong opioids, which may produce tolerance and alter dose requirements
- Known or suspected pseudocholinesterase deficiency (although remifentanil is not primarily metabolized by this enzyme)
Remifentanil produces dose-dependent respiratory depression and apnea. When given as a bolus or at higher infusion rates, patients who are not ventilated may stop breathing entirely. Continuous monitoring of oxygen saturation, end-tidal carbon dioxide, respiratory rate, and consciousness level is mandatory in all patients receiving remifentanil who are not being mechanically ventilated. Equipment for immediate airway management, oxygen delivery, and assisted ventilation must be at the bedside.
Rapid intravenous bolus injection or high infusion rates of remifentanil can cause generalised skeletal muscle rigidity, including rigidity of the chest wall (“wooden chest syndrome”) that may prevent effective ventilation. Risk is reduced by using slow injection (administered over at least 30–60 seconds), pretreatment with an intravenous hypnotic, or concurrent use of a neuromuscular blocking drug. Established rigidity is treated by stopping remifentanil, giving a neuromuscular blocker, and assisting ventilation until spontaneous breathing returns.
Because remifentanil has essentially no residual analgesic effect after the infusion is stopped, acute pain can emerge rapidly — sometimes dramatically — in the early recovery period. In addition, prolonged or high-dose remifentanil can precipitate opioid-induced hyperalgesia, in which the patient becomes more sensitive to pain. To prevent this, your anesthesiologist will usually administer a longer-acting opioid such as morphine, hydromorphone, or oxycodone, or use regional anesthetic techniques, well before the remifentanil infusion is discontinued.
Pregnancy and Breastfeeding
If you are pregnant, breastfeeding, suspect you may be pregnant, or are planning to become pregnant, inform your physician before you receive Remifentanil Hameln. Although remifentanil crosses the placenta like other opioids, the very short half-life means that neonatal respiratory depression is less likely than with longer-acting opioids.
Pregnancy: There are no adequate and well-controlled studies of remifentanil in pregnant women. Animal studies have not demonstrated teratogenic effects, but the safety of remifentanil during pregnancy has not been fully established. Remifentanil should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. If used during labor or cesarean delivery, the neonate must be observed for respiratory depression.
Breastfeeding: It is not known whether remifentanil is excreted in human breast milk. Because the drug is rapidly metabolized to inactive compounds in minutes, clinically significant exposure through breast milk is considered extremely unlikely after a single perioperative exposure. Breastfeeding may typically be resumed within hours of the last dose, although you should discuss timing with your healthcare team.
Use in Elderly Patients
Elderly patients (those 65 years and older) often require lower doses of remifentanil than younger adults. Age-related decreases in cardiac output, reductions in volume of distribution, and changes in receptor sensitivity all contribute to increased drug effects at any given dose. Initial bolus doses and infusion rates should generally be reduced by approximately 50 percent in the elderly, with further titration according to individual response.
Driving and Operating Machinery
Remifentanil itself is eliminated too quickly to have residual effects on psychomotor performance several hours after administration. However, anesthesia as a whole, along with any other sedative medications used during the procedure, commonly impairs driving ability, reaction time, and decision-making for at least 24 hours. You must not drive, operate machinery, make important legal or financial decisions, or care for young children unsupervised for at least 24 hours after any anesthetic in which remifentanil is used, and your physician may recommend a longer period depending on the procedure.
How Does Remifentanil Hameln Interact with Other Drugs?
Quick Answer: Remifentanil has clinically significant interactions with benzodiazepines, propofol, volatile anesthetics, and other CNS depressants (additive sedation and respiratory depression), with beta-blockers and calcium channel blockers (additive bradycardia and hypotension), and with partial opioid agonists such as buprenorphine and nalbuphine (may precipitate withdrawal). Unlike fentanyl, remifentanil is not metabolized by cytochrome P450 enzymes, so it lacks the clinically important interactions seen with CYP3A4 inhibitors.
Drug interactions with remifentanil are largely pharmacodynamic — that is, they result from combined effects on shared physiological targets rather than from changes in remifentanil metabolism. Because remifentanil is broken down by non-specific esterases, it is not metabolized to any clinically significant extent by cytochrome P450 enzymes, and it does not induce or inhibit them. This is an important safety advantage over fentanyl, sufentanil, and alfentanil, which are CYP3A4 substrates and are affected by enzyme inhibitors such as macrolide antibiotics, azole antifungals, and HIV protease inhibitors.
Major Interactions — Contraindicated or Avoid
| Drug / Drug Class | Interaction Effect | Clinical Recommendation |
|---|---|---|
| MAO Inhibitors (e.g., phenelzine, tranylcypromine, moclobemide, selegiline) | Risk of serotonin syndrome, severe hypertension, excitation, or fatal cardiovascular collapse | Discontinue MAOI at least 2 weeks before elective surgery |
| Benzodiazepines (e.g., midazolam, diazepam, lorazepam) | Profound additive sedation, respiratory depression, hypotension, coma, and death | Use only when clinically essential; reduce doses of both agents and monitor ventilation continuously |
| Partial opioid agonists/antagonists (buprenorphine, nalbuphine, pentazocine, butorphanol) | May precipitate acute opioid withdrawal and reduce analgesic efficacy | Avoid co-administration; discontinue partial agonists before surgery where possible |
| Gabapentinoids (gabapentin, pregabalin) | Increased risk of opioid-induced respiratory depression and sedation | Use with caution; consider dose reduction of both agents and extended postoperative monitoring |
| Alcohol and illicit CNS depressants | Additive CNS and respiratory depression, unpredictable potentiation | Disclose recent use to the anesthesiologist; postpone elective procedures if acute intoxication is present |
Moderate Interactions — Use with Caution
| Drug / Drug Class | Interaction Effect | Clinical Recommendation |
|---|---|---|
| Intravenous hypnotics (propofol, thiopental, etomidate) | Synergistic reduction of conscious level and blood pressure | Reduce hypnotic induction dose by approximately 25–50 percent when combined with remifentanil |
| Volatile anesthetics (isoflurane, sevoflurane, desflurane) | Reduced MAC (minimum alveolar concentration) requirement; additive cardiovascular depression | Reduce volatile agent end-tidal concentration and titrate to maintain hemodynamic stability |
| Beta-blockers (e.g., metoprolol, bisoprolol, atenolol) | Additive bradycardia and hypotension, particularly during induction | Administer with caution; have atropine and sympathomimetic support available |
| Calcium channel blockers (e.g., diltiazem, verapamil, amlodipine) | Additive bradycardia and hypotension | Monitor heart rate and blood pressure closely during induction and maintenance |
| Neuromuscular blocking agents (e.g., rocuronium, vecuronium, cisatracurium) | No direct pharmacological interaction, but muscle rigidity from remifentanil can mimic incomplete relaxation | Use standard neuromuscular monitoring; distinguish rigidity from partial blockade |
| Serotonergic agents (SSRIs, SNRIs, tricyclic antidepressants, tramadol) | Theoretical risk of serotonin syndrome when combined with mu-opioid agonists | Monitor for autonomic instability, neuromuscular hyperactivity, and altered mental status |
Remifentanil is metabolized almost entirely by non-specific esterases located in blood and tissues. It is not a substrate for cytochrome P450 enzymes, including CYP3A4, and therefore does not interact with CYP inhibitors such as ketoconazole, ritonavir, or erythromycin in the way that fentanyl and its longer-acting analogues do. Similarly, remifentanil clearance is not meaningfully altered by severe hepatic impairment, end-stage renal disease, or hemodialysis. This combination of features makes remifentanil especially valuable in critically ill patients with multi-organ dysfunction.
What Is the Correct Dosage of Remifentanil Hameln?
Quick Answer: Remifentanil Hameln is dosed individually by the anesthesiologist based on the patient’s body weight, age, type and duration of surgery, concurrent anesthetic agents, and clinical response. It is typically given as an intravenous infusion in micrograms per kilogram per minute, sometimes preceded by a slow bolus. In obese patients, dosing should generally be based on ideal body weight. It is never self-administered.
Because remifentanil has a very steep dose-response relationship and a very rapid onset of effect, dosing is always individualised and titrated to clinical response. The following guidance reflects the approved dosing information from the European Medicines Agency (EMA) Summary of Product Characteristics and national formularies such as the British National Formulary (BNF). All doses must be calculated, prepared, and administered by trained anesthesia or intensive care personnel.
Adults — Induction of Anesthesia
Induction with a Hypnotic Agent
For induction of anesthesia, remifentanil is usually administered as a continuous infusion together with a hypnotic such as propofol or thiopental. A common infusion rate during induction is 0.5 to 1 microgram per kilogram per minute, started 30–60 seconds before the hypnotic agent. A slow bolus can be added if rapid onset of analgesia is required, but bolus injection should always be given over at least 30 seconds to reduce the risk of muscle rigidity, bradycardia, and hypotension.
Adults — Maintenance of Anesthesia
With Nitrous Oxide, Propofol, or Volatile Anesthetics
During the maintenance phase, remifentanil infusion rates are adjusted to the surgical stimulus and to the concurrent anesthetic agent. Typical maintenance infusion rates in adults range from 0.05 to 2 micrograms per kilogram per minute, with most procedures requiring 0.1 to 0.5 micrograms per kilogram per minute. Supplemental boluses of 0.5 to 1 microgram per kilogram (over at least 30 seconds) can be given to cover short periods of intense stimulation such as intubation or incision.
Adults — Analgesia During Conscious Procedures
Monitored Anesthesia Care
For analgesia in spontaneously breathing adults undergoing conscious procedures, continuous infusion rates are typically 0.05 to 0.1 micrograms per kilogram per minute, carefully titrated to maintain responsiveness and spontaneous ventilation. Bolus injections in awake patients are generally avoided because of the high risk of apnea and rigidity, but if used, they must be given very slowly by a clinician ready to manage the airway.
Adults — Intensive Care Sedation
Mechanically Ventilated Adults (≥18 years)
For sedation and analgesia of mechanically ventilated adult intensive care patients, the recommended starting infusion rate is 0.1 microgram per kilogram per minute, titrated in small increments (typically 0.025 microgram per kilogram per minute every 5–10 minutes) to achieve the desired level of sedation, usually up to a maximum of around 0.74 microgram per kilogram per minute. A separate sedative such as propofol or midazolam may be required because remifentanil does not reliably produce hypnosis at sedation infusion rates. Continuous infusion for longer than 3 days is not recommended.
Children (Aged 1 Year and Over) — Maintenance of Anesthesia
Pediatric Intravenous Use
In children aged 1 year and older, remifentanil is approved for the maintenance of general anesthesia when combined with an intravenous or inhaled anesthetic. Typical infusion rates range from 0.05 to 1.3 micrograms per kilogram per minute, with most cases requiring 0.25 microgram per kilogram per minute. It is not recommended for induction of anesthesia in children. Continuous respiratory and cardiovascular monitoring by an anesthesiologist experienced in pediatric anesthesia is mandatory throughout the procedure and recovery period.
Special Populations Requiring Dose Adjustment
- Elderly patients (>65 years): Reduce initial bolus and infusion rates by approximately 50 percent. Elderly patients are more sensitive to the respiratory and cardiovascular effects of all opioids, including remifentanil.
- Obese patients: Dose should generally be calculated based on ideal body weight rather than total body weight to avoid relative overdose.
- Hepatic impairment: No dose adjustment is required because metabolism is independent of liver function. Increased sensitivity to respiratory depression has been reported in some severely ill patients; titrate to effect.
- Renal impairment: No dose adjustment is required. A minor and clinically insignificant inactive metabolite (remifentanil acid) can accumulate in renal failure but does not require dose modification.
- Cardiac surgery patients: Higher doses are commonly used; titration must balance analgesia with the risk of bradycardia and hypotension. Intraoperative awareness has been reported when remifentanil is not combined with adequate hypnotic agents.
- Hypovolemia and shock: Reduce initial doses and correct intravascular volume before induction to minimize hypotension.
Infusion Preparation and Delivery
Remifentanil Hameln must be reconstituted with a compatible diluent (water for injections, 0.9 percent sodium chloride, or 5 percent glucose) to a concentration of 1 mg per milliliter, then further diluted to the desired final concentration for infusion (typically 20 to 250 micrograms per milliliter). The drug should always be administered through an infusion pump using a dedicated intravenous line or a Y-connector close to the venous cannula, because dead space in the infusion line can delay dose changes. When the infusion is stopped, the line should be cleared to prevent inadvertent administration of residual drug.
Missed Dose
Because remifentanil is administered only in controlled hospital settings as an infusion or intravenous injection, the concept of a missed dose does not apply in the usual sense. If an infusion is accidentally interrupted, the drug effect will dissipate within minutes and will need to be re-established by resuming the infusion under medical supervision, with careful reassessment of analgesia and anesthetic depth.
Overdose
As with other potent opioids, overdose of remifentanil produces severe respiratory depression or apnea, loss of consciousness, bradycardia, hypotension, muscle rigidity, and cardiovascular collapse. Because remifentanil is only administered by trained personnel in monitored settings, overdose is rare and is usually the result of pump programming error or accidental bolus. Treatment consists of immediately stopping the infusion, ensuring a patent airway, providing assisted ventilation with oxygen, and supporting the circulation with intravenous fluids and vasopressors as needed.
The opioid antagonist naloxone can reverse opioid effects, but is usually not required because remifentanil’s effects dissipate spontaneously within 5–10 minutes of stopping the infusion. Naloxone may be useful for residual muscle rigidity or if other long-acting opioids have also been administered. Atropine or glycopyrrolate can reverse opioid-induced bradycardia.
If a patient experiences breathing difficulties, loss of consciousness, or severe hemodynamic compromise during or after remifentanil administration, inform the supervising physician and nursing team immediately. Outside a healthcare facility, call your local emergency number without delay. Do not attempt to treat opioid overdose at home.
What Are the Side Effects of Remifentanil Hameln?
Quick Answer: The most common side effects are muscle rigidity, nausea, vomiting, hypotension (low blood pressure), and bradycardia (slow heart rate). Other common effects include shivering, postoperative pain, and pruritus (itching). Serious but less common problems include respiratory depression, apnea, cardiac arrest, and anaphylaxis. Because remifentanil leaves the body rapidly, acute postoperative pain can emerge quickly after the infusion is stopped.
Like all opioid medications, Remifentanil Hameln can cause side effects, although not every patient will experience them. Most reactions are dose-related and short-lived because the drug itself is cleared within minutes of stopping the infusion. The severity of side effects depends on the infusion rate, the route and speed of any bolus, the concurrent use of other anesthetic or sedative drugs, and individual patient factors such as age, body weight, and cardiovascular status. Side effects during and immediately after the procedure are managed by the anesthesiologist and recovery nursing staff.
The following side effects are organised by frequency according to international pharmacovigilance conventions used in the EMA Summary of Product Characteristics:
Very Common
May affect more than 1 in 10 patients
- Muscle rigidity, including chest wall rigidity that may interfere with ventilation
- Hypotension (low blood pressure)
- Nausea and vomiting
Common
May affect up to 1 in 10 patients
- Bradycardia (slow heart rate)
- Respiratory depression, including apnea
- Pruritus (itching) and generalised skin rash
- Shivering and postoperative chills
- Acute postoperative pain as drug effect dissipates
- Headache and dizziness
- Sedation and delayed emergence from anesthesia
Uncommon
May affect up to 1 in 100 patients
- Marked hypertension (high blood pressure), particularly on emergence
- Tachycardia (rapid heart rate)
- Constipation, dry mouth, or altered gastrointestinal motility
- Hypoxia (low blood oxygen)
- Agitation, confusion, or delirium on emergence
- Injection-site reactions including local pain and irritation
- Muscle twitching (myoclonus) and involuntary movements
- Visual disturbances
- Urinary retention
Rare / Not Known
May affect fewer than 1 in 1,000 patients or cannot be estimated from available data
- Asystole (cardiac arrest) — typically in patients receiving other cardiovascular depressants
- Severe allergic reactions including anaphylaxis (rash, swelling, severe breathing difficulty, and shock)
- Complete heart block or severe arrhythmia
- Laryngospasm (spasm of the throat muscles)
- Seizures or convulsions
- Tolerance, physical dependence, or opioid-induced hyperalgesia with prolonged use
- Serotonin syndrome when combined with serotonergic drugs
- Opioid withdrawal following rapid discontinuation after prolonged use in intensive care
Side Effects Unique to Remifentanil
Two patterns of adverse effect deserve specific emphasis because they are more prominent with remifentanil than with longer-acting opioids. The first is acute postoperative pain: because the analgesic effect dissipates within minutes of stopping the infusion, patients can wake in severe pain unless longer-acting analgesia has been established in advance. Modern anesthetic practice therefore includes transition planning, in which morphine, hydromorphone, oxycodone, regional anesthesia, or multimodal analgesia is introduced before remifentanil is discontinued.
The second is opioid-induced hyperalgesia, a paradoxical increase in pain sensitivity that can follow high-dose or prolonged remifentanil exposure. Although its clinical importance remains debated, strategies to reduce its likelihood include using the lowest effective infusion rate, co-administering non-opioid analgesics such as ketamine, paracetamol, and NSAIDs, and avoiding unnecessarily high remifentanil doses during long procedures.
Side Effects in Children
The pattern of side effects in children aged 1 year and older is broadly similar to that in adults. Nausea, vomiting, and shivering are particularly common in pediatric recovery, while muscle rigidity and hemodynamic changes are dose-related and responsive to careful titration. Continuous respiratory and cardiovascular monitoring by pediatric anesthesia-trained staff is essential throughout the procedure and recovery.
If you experience any side effects after receiving Remifentanil Hameln — including those not listed above — report them to your healthcare provider. You can also report side effects directly to your national medicines regulatory authority. By reporting side effects, you help regulators and clinicians monitor the safety of medicines and improve care for future patients.
How Should You Store Remifentanil Hameln?
Quick Answer: Remifentanil Hameln vials must be stored below 25°C in the original carton to protect from light, and must not be frozen. Once reconstituted and diluted, the solution should normally be used immediately and any unused portion discarded. Storage and disposal are the responsibility of the hospital pharmacy and the attending healthcare team.
Remifentanil Hameln is a controlled substance that requires strict storage and handling procedures under national opioid regulations. Because it is a hospital-only medication, patients are not typically responsible for its storage at home, but understanding these requirements contributes to general medication safety awareness and to the safe operation of hospital supply chains.
- Temperature: Store the unopened vial at or below 25°C (77°F). Do not refrigerate and do not freeze.
- Light protection: Keep vials in the original outer carton to protect from light.
- Before reconstitution: Do not use the vial if the lyophilised powder shows signs of deterioration, if the vial is cracked, or if the label is missing or illegible.
- After reconstitution: The reconstituted solution (1 mg/ml) is intended for immediate further dilution. It should not be administered directly without further dilution.
- After dilution: From a microbiological standpoint, the diluted solution should be used immediately. If it is not used immediately, in-use storage times and conditions are the responsibility of the user; chemical and physical stability of the final diluted solution has been demonstrated for up to 24 hours at 2–8°C, provided dilution has been performed under controlled and validated aseptic conditions.
- Expiry date: Do not use after the expiry date printed on the label and carton (EXP). The expiry date refers to the last day of the stated month.
- Visual inspection: Before administration, check that the reconstituted solution is clear, colorless, and free from visible particles. Discard any solution that is discolored or contains particulate matter.
- Single-use only: Any unused portion of the vial or diluted solution must be discarded and documented according to local controlled-substance procedures.
- Child safety and access control: Keep this medicine out of the reach of children and unauthorised personnel at all times; stock is held in secure controlled-drug cabinets in hospital pharmacies and operating areas.
Healthcare professionals are responsible for the correct storage, preparation, administration, and disposal of Remifentanil Hameln in accordance with local laws on controlled substances and institutional pharmacy policies.
What Does Remifentanil Hameln Contain?
Quick Answer: The active substance is remifentanil (as remifentanil hydrochloride). Other ingredients are glycine and hydrochloric acid. It is a white to off-white lyophilised powder supplied in clear glass vials, designed to be reconstituted before intravenous administration.
Active Substance
The active pharmaceutical ingredient is remifentanil, present in the formulation as remifentanil hydrochloride. Each vial contains the equivalent of 1 mg, 2 mg, or 5 mg of remifentanil base:
| Strength | Remifentanil Base | Remifentanil Hydrochloride | Concentration After Reconstitution |
|---|---|---|---|
| 1 mg vial | 1 mg | 1.1 mg | 1 mg/ml (reconstitute with 1 ml) |
| 2 mg vial | 2 mg | 2.2 mg | 1 mg/ml (reconstitute with 2 ml) |
| 5 mg vial | 5 mg | 5.5 mg | 1 mg/ml (reconstitute with 5 ml) |
Inactive Ingredients (Excipients)
- Glycine: An amino acid used as a bulking agent and pH adjuster in the lyophilised formulation. Glycine is the main reason remifentanil must never be administered by the epidural or intrathecal route, because within the central nervous system it acts as an inhibitory neurotransmitter and could cause reversible weakness, paralysis, or other neurological effects.
- Hydrochloric acid: Used in small amounts during manufacture to adjust the pH of the formulation.
Remifentanil Hameln does not contain any preservatives. It is not known to contain any ingredient of human or animal origin.
Physical Appearance and Packaging
Remifentanil Hameln is supplied as a white to off-white lyophilised powder for concentrate for solution for injection or infusion. The powder is packaged in clear, colorless glass vials sealed with a rubber stopper and aluminum over-seal. Vials are available in packs containing one or more vials, although not all pack sizes may be marketed in every country.
Compatibility Information for Healthcare Professionals
Remifentanil Hameln is compatible with the following intravenous infusion fluids when administered through a dedicated intravenous line or at a running intravenous catheter: water for injections, 0.9 percent sodium chloride, 5 percent glucose (dextrose), 5 percent glucose with 0.9 percent sodium chloride, and Ringer’s lactate solution. It should not be added to Ringer’s lactate solution and must not be reconstituted or diluted with other fluids unless specifically validated.
Remifentanil Hameln is physically incompatible with propofol and must not be mixed in the same syringe — both drugs are frequently co-administered, but through separate infusion lines or via Y-site administration very close to the venous cannula. Direct mixing with blood, serum, or plasma is also contraindicated because non-specific esterases in these fluids will degrade the drug. Remifentanil must not be mixed with other drugs in the same syringe or infusion bag unless compatibility has been explicitly established.
Frequently Asked Questions About Remifentanil Hameln
Remifentanil Hameln is an ultra-short-acting opioid analgesic used intravenously during general anesthesia. It provides pain relief during the induction and maintenance of anesthesia for surgical procedures, supports mechanical ventilation in intensive care patients aged 18 and over, and can be used to provide sedation and analgesia during conscious procedures such as awake fibreoptic intubation, shockwave lithotripsy, or interventional radiology. It is administered only in hospital settings by or under the direct supervision of an anesthesiologist.
Remifentanil has a very rapid onset, typically producing clinical effects within one minute of intravenous administration. Its defining feature is an ultra-short context-sensitive half-life of approximately 3 to 4 minutes that remains constant regardless of how long the drug has been infused. This means clinical effects dissipate rapidly once the infusion is stopped, allowing precise titration and fast recovery. By contrast, most other opioids accumulate with prolonged infusion and take hours or days to wear off.
Remifentanil Hameln must not be administered by the epidural or intrathecal route because its formulation contains glycine as an excipient. Glycine is an inhibitory neurotransmitter in the spinal cord and could cause reversible motor weakness, paralysis, or other neurological effects if introduced near the central nervous system. Remifentanil is approved only for intravenous administration. Other opioids such as morphine, fentanyl, or sufentanil are used when an epidural or intrathecal opioid is needed.
The most common side effects include muscle rigidity, hypotension (low blood pressure), nausea and vomiting, bradycardia (slow heart rate), and pruritus (itching). Because remifentanil provides no residual analgesia after the infusion is stopped, acute postoperative pain can emerge suddenly if longer-acting analgesia has not been given in advance. Prolonged or high-dose use can rarely cause opioid-induced hyperalgesia, in which patients become more sensitive to pain. Serious but rare complications include apnea, cardiac arrest, and anaphylaxis.
No routine dose adjustment is required for kidney or liver disease. Remifentanil is unique among potent opioids because its metabolism is almost entirely independent of liver and kidney function — it is broken down by non-specific esterases in blood and tissues into inactive metabolites. This makes it particularly useful in critically ill patients with severe hepatic or renal impairment, although standard clinical monitoring and titration to effect are still required in every patient.
Remifentanil is approved in children aged 1 year and older for intravenous use during the maintenance of general anesthesia. It is not recommended for induction of anesthesia in children due to limited data in this age group. Safety and efficacy in children under 1 year of age have not been established, and it is not approved for use in neonates or infants under 12 months. All pediatric use requires administration by an anesthesiologist experienced in pediatric care.
Like all mu-opioid agonists, remifentanil has the potential for tolerance, physical dependence, and misuse. However, because it is almost exclusively used during anesthesia and intensive care in short, tightly controlled infusions, and because patients do not take the drug home, the risk of addiction from a single perioperative exposure is very low. The risk is higher when remifentanil is used over several days in intensive care, where tolerance and withdrawal symptoms can occur on discontinuation and a planned opioid taper may be required.
References and Sources
This article is based on the following peer-reviewed sources, international guidelines, and regulatory documents:
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