Dridol (Droperidol 2.5 mg/ml)

What Is Dridol and What Is It Used For?

Dridol contains droperidol, a butyrophenone neuroleptic that acts as a potent dopamine D2 receptor antagonist. It is used primarily for the prevention and treatment of postoperative nausea and vomiting (PONV), sedation during surgical and diagnostic procedures, and management of acute agitation.

Droperidol was first synthesized in 1961 by Paul Janssen at Janssen Pharmaceutica and has been used in clinical practice for over six decades. It belongs to the butyrophenone class of neuroleptic agents, which also includes haloperidol. Droperidol exerts its pharmacological effects primarily through antagonism of dopamine D2 receptors in the central nervous system, particularly in the chemoreceptor trigger zone (CTZ) of the medulla oblongata, which is the brain region responsible for the emetic (vomiting) reflex.

The antiemetic properties of droperidol make it particularly valuable in the perioperative setting. Postoperative nausea and vomiting (PONV) is one of the most common complications following general anesthesia, affecting approximately 30% of all surgical patients and up to 80% of high-risk patients. PONV can cause significant patient discomfort, delay hospital discharge, and in some cases lead to complications such as aspiration, wound dehiscence, or esophageal rupture. Droperidol has been shown in numerous randomized controlled trials and systematic reviews to be one of the most effective agents for PONV prophylaxis.

Beyond its antiemetic role, droperidol has several other established clinical applications. It is used as a component of neuroleptanalgesia, a technique combining a neuroleptic agent with an opioid analgesic (typically fentanyl) to produce a state of sedation and analgesia suitable for certain surgical and diagnostic procedures. The combination of droperidol and fentanyl was historically marketed as Innovar and represented one of the first balanced anesthesia approaches. In emergency medicine, low-dose droperidol is recognized as an effective treatment for acute undifferentiated agitation, with a rapid onset of action and a favourable safety profile when used appropriately.

Droperidol also possesses mild alpha-1 adrenergic blocking activity, which can cause mild peripheral vasodilation and a modest decrease in blood pressure. This property contributes to its sedative effects but also necessitates hemodynamic monitoring during administration. The medication is rapidly absorbed after intramuscular injection and reaches peak plasma concentrations within 15 to 20 minutes. When given intravenously, the onset of action is typically within 3 to 10 minutes. The duration of the sedative and antiemetic effects generally lasts 2 to 4 hours, although the medication's pharmacological half-life is approximately 2 to 3 hours in adults.

What Should You Know Before Receiving Dridol?

Before receiving Dridol, your healthcare provider will assess your medical history, current medications, and cardiac risk factors. Droperidol should not be given to patients with known QT prolongation, uncorrected electrolyte imbalances, or those taking other QT-prolonging medications without careful risk-benefit assessment.

Contraindications

Dridol must not be administered in the following situations:

• Known hypersensitivity: Allergy to droperidol, other butyrophenones (such as haloperidol), or any of the excipients in the formulation
• Known QT prolongation: Patients with congenital long QT syndrome or a documented corrected QT interval (QTc) exceeding 440 milliseconds in men or 450 milliseconds in women
• Severe hypokalemia or hypomagnesemia: Uncorrected electrolyte disturbances significantly increase the risk of cardiac arrhythmias when combined with QT-prolonging agents
• Concurrent use of certain QT-prolonging drugs: Including Class IA antiarrhythmics (quinidine, procainamide), Class III antiarrhythmics (amiodarone, sotalol), certain antibiotics (erythromycin IV, moxifloxacin), and some antipsychotics
• Pheochromocytoma: Known or suspected pheochromocytoma, as droperidol may trigger a hypertensive crisis in these patients
• Comatose states: Patients in a comatose state or with severely depressed consciousness level from any cause

Your anesthesiologist or prescribing physician will carefully screen for these contraindications before administering droperidol. In many clinical settings, a pre-procedure checklist and 12-lead ECG are performed to identify patients who may be at elevated risk for cardiac complications. If any contraindication is identified, an alternative antiemetic or sedative agent will be selected.

Warnings and Precautions

Special care and additional monitoring are required when droperidol is given to patients with any of the following conditions or circumstances:

• Cardiac disease: Patients with congestive heart failure, bradycardia, cardiac hypertrophy, or a history of arrhythmias require careful cardiac monitoring during and after droperidol administration
• Electrolyte disturbances: Hypokalemia, hypomagnesemia, and hypocalcemia must be corrected before droperidol is administered, as these conditions increase the risk of QT prolongation and torsades de pointes
• Elderly patients: Older adults are more susceptible to the hypotensive and sedative effects of droperidol and may require lower doses. Age-related declines in hepatic and renal function can prolong the drug's effects
• Hepatic or renal impairment: Patients with significant liver or kidney disease may metabolize and excrete droperidol more slowly, necessitating dose reduction and extended monitoring
• Parkinson's disease: Droperidol is a dopamine antagonist and may worsen parkinsonian symptoms. Alternative antiemetics (such as ondansetron) should be considered for these patients
• History of neuroleptic malignant syndrome: Patients with a prior episode of neuroleptic malignant syndrome (NMS) should generally not receive droperidol, as NMS may recur with any dopamine-blocking agent
• Epilepsy: Droperidol may lower the seizure threshold. Use with caution in patients with a history of seizures

Healthcare professionals administering droperidol should have immediate access to resuscitation equipment, including cardiac defibrillation capability, intravenous fluids, and vasopressor agents. Continuous pulse oximetry and regular blood pressure monitoring are recommended throughout the period of drug effect. Patients should remain under direct observation for a minimum of 30 minutes after intravenous administration and longer following intramuscular injection.

Pregnancy and Breastfeeding

The use of droperidol during pregnancy should be limited to situations where the expected clinical benefit clearly outweighs the potential risk to the fetus. Animal reproductive studies have shown some evidence of teratogenic effects at high doses, although controlled studies in pregnant women are limited. Droperidol does cross the placental barrier, and neonatal respiratory depression has been reported when the drug was administered close to delivery.

If droperidol is used during labour or caesarean section delivery, the neonate should be closely monitored for signs of respiratory depression, sedation, and extrapyramidal symptoms. Equipment for neonatal resuscitation should be immediately available. The American Society of Anesthesiologists and the European Society of Anaesthesiology generally consider low-dose droperidol acceptable for PONV prophylaxis during caesarean section under general anesthesia when the benefits are judged to outweigh the risks.

It is not conclusively established whether droperidol is excreted in human breast milk. However, given its lipophilic nature and the fact that related butyrophenones are known to pass into breast milk, caution is advised. If droperidol is administered to a breastfeeding mother, it is prudent to suspend breastfeeding for at least 24 hours after the dose to minimize potential infant exposure. Discuss alternative antiemetic options with your healthcare provider if you are breastfeeding.

How Does Dridol Interact with Other Drugs?

Droperidol has clinically significant interactions with other QT-prolonging medications, CNS depressants, opioids, and antihypertensive agents. Concurrent use of droperidol with drugs that prolong the QT interval is generally contraindicated or requires careful ECG monitoring. Additive sedation occurs when combined with opioids, benzodiazepines, or other CNS depressants.

Drug interactions with droperidol can be broadly categorized into pharmacodynamic interactions (where two drugs have additive or opposing effects on the same physiological system) and pharmacokinetic interactions (where one drug affects the absorption, distribution, metabolism, or elimination of another). The most clinically significant interactions involve the QT-prolonging effect of droperidol, its dopamine-blocking activity, and its central nervous system depressant properties.

Droperidol is metabolized primarily in the liver by cytochrome P450 enzymes, including CYP1A2 and CYP3A4. Medications that inhibit or induce these enzymes may alter droperidol plasma concentrations, although clinically significant pharmacokinetic interactions are less commonly reported than pharmacodynamic ones. The relatively short duration of action and single-dose administration pattern of droperidol reduces the clinical impact of most pharmacokinetic interactions.

Your anesthesiologist or prescribing physician will review your complete medication list before administering droperidol. This includes prescription drugs, over-the-counter medications, herbal supplements, and recreational substances. Accurate medication reconciliation is essential for minimizing the risk of dangerous drug interactions in the perioperative and emergency settings.

Major Interactions

The interaction table above is not exhaustive. Many medications, including certain antihistamines, tricyclic antidepressants, and some antifungal agents, may also prolong the QT interval or interact with droperidol through other mechanisms. Always ensure that your complete medication history is available to the treating physician before droperidol is administered.

What Is the Correct Dosage of Dridol?

Dridol is available as a 2.5 mg/ml solution for injection. Dosing depends on the indication, patient age, weight, and clinical status. For PONV prophylaxis, the typical adult dose is 0.625 to 1.25 mg IV at the end of surgery. All doses are determined and administered by healthcare professionals.

Droperidol dosing has evolved considerably since the medication was first introduced, with modern practice favouring substantially lower doses than those used historically. The shift toward low-dose droperidol is based on evidence that antiemetic efficacy is maintained at doses of 0.625 to 1.25 mg, while the risk of adverse effects, particularly QT prolongation and extrapyramidal symptoms, is significantly reduced compared to the higher doses (2.5 to 10 mg) used in earlier decades.

Adults

Children and Adolescents

Elderly Patients

Missed Dose

The concept of a missed dose does not typically apply to droperidol, as it is administered by healthcare professionals in acute clinical settings rather than taken on a regular schedule by the patient. If droperidol was planned as part of an anesthetic protocol but was not administered, the decision to give it late or substitute an alternative antiemetic rests with the attending anesthesiologist or physician, based on the patient's current clinical status and ongoing risk of nausea or vomiting.

Overdose

What Are the Side Effects of Dridol?

Like all medicines, Dridol can cause side effects, although not everybody experiences them. The most common side effects are drowsiness and mild hypotension. The most clinically significant adverse effect is QT interval prolongation, which may rarely lead to serious cardiac arrhythmias. Extrapyramidal symptoms such as dystonia and akathisia can also occur.

The safety profile of droperidol is well-established through decades of clinical use and numerous published studies. At the low doses currently recommended for PONV prophylaxis (0.625 to 1.25 mg), side effects are generally mild and self-limiting. Higher doses, as used for sedation or acute agitation, carry a greater risk of adverse effects, particularly extrapyramidal symptoms, hypotension, and QT prolongation.

In 2001, the United States Food and Drug Administration (FDA) issued a black box warning for droperidol regarding QT prolongation and the risk of torsades de pointes. This warning was controversial and has been extensively debated in the medical literature, with many anesthesiologists and emergency physicians arguing that the risk was overstated based on the available evidence. Subsequent large-scale studies and meta-analyses have demonstrated that the risk of clinically significant QT prolongation at low doses (under 2.5 mg) is very low, particularly in patients without pre-existing cardiac risk factors. Nevertheless, the warning prompted the adoption of ECG monitoring protocols that remain standard practice in many institutions.

It is important to report any suspected side effects to your healthcare provider. Reporting adverse drug reactions contributes to the ongoing monitoring of the benefit-risk balance of medications and helps improve drug safety for all patients.

Extrapyramidal symptoms (EPS) are among the most characteristic adverse effects of dopamine-blocking agents like droperidol. These include acute dystonia (involuntary muscle contractions causing abnormal postures, particularly of the head, neck, and eyes), akathisia (an inner sense of restlessness with an inability to sit still), and rarely, tardive dyskinesia with repeated exposure. Acute dystonic reactions typically respond rapidly to intravenous anticholinergic agents such as benztropine (1 to 2 mg IV) or diphenhydramine (25 to 50 mg IV). Young adults and children appear to be at higher risk for EPS than older patients.

How Should You Store Dridol?

Dridol solution for injection should be stored below 25°C (77°F) in the original packaging, protected from light. As a hospital-use medication, storage is typically managed by the pharmacy department. Do not use after the expiry date.

Droperidol solution for injection should be stored at controlled room temperature, not exceeding 25°C (77°F). The ampoules or vials should be kept in their original outer carton to protect the solution from light, as droperidol may undergo photodegradation when exposed to direct or prolonged light. Do not freeze the solution. If the solution appears discoloured, cloudy, or contains particulate matter, it should not be used and should be disposed of according to local pharmaceutical waste guidelines.

In hospital pharmacies, droperidol is typically stored in a temperature-controlled medication room or automated dispensing cabinet. The solution does not contain preservatives in single-use ampoule presentations, meaning any unused portion must be discarded immediately after opening. Multi-dose vials, where available, should be used according to the manufacturer's instructions regarding in-use shelf life after first opening, typically within 24 hours when stored at 2 to 8°C.

As with all medications, droperidol should be kept out of the reach and sight of children. Although this medication is ordinarily stored in clinical facilities rather than in homes, healthcare workers should ensure that ampoules are not left unattended in patient care areas. Do not use Dridol after the expiry date printed on the ampoule and outer carton. The expiry date refers to the last day of the stated month.

What Does Dridol Contain?

Each millilitre of Dridol solution for injection contains 2.5 mg of droperidol as the active substance, along with pharmaceutical excipients required for an injectable formulation, typically including lactic acid or tartaric acid for pH adjustment and water for injections.

The active ingredient in Dridol is droperidol (INN), present at a concentration of 2.5 mg per millilitre of solution. Droperidol is a butyrophenone derivative with the chemical name 1-{1-[4-(4-fluorophenyl)-4-oxobutyl]-1,2,3,6-tetrahydropyridin-4-yl}-1,3-dihydro-2H-benzimidazol-2-one. Its molecular formula is C₂₂H₂₂FN₃O₂ and its molecular weight is approximately 379.4 g/mol. The substance is a white to off-white powder that is practically insoluble in water but soluble in acidic aqueous solutions.

The injectable formulation contains the following excipients (inactive ingredients) that serve specific pharmaceutical functions:

• Lactic acid or tartaric acid: Used to adjust the pH of the solution to an appropriate range (typically pH 3.0 to 3.8) that maintains droperidol in solution and ensures compatibility with intravenous administration
• Water for injections: The vehicle (solvent) for the injectable preparation, meeting pharmacopoeial standards for sterility and pyrogenicity
• Sodium hydroxide (if needed): May be added in small quantities for fine pH adjustment during manufacturing

The solution is clear, colourless to slightly yellowish, and is presented in glass ampoules or vials. Each ampoule typically contains 1 ml (2.5 mg droperidol) or 2 ml (5 mg droperidol) of solution. The glass used for the primary container is Type I hydrolytic glass, which provides the highest level of chemical resistance and is standard for parenteral pharmaceutical products.

If you have known allergies to any pharmaceutical excipient, inform your healthcare provider before receiving Dridol. While the excipient profile of injectable droperidol is simple compared to oral dosage forms, hypersensitivity to any component, however rare, must be identified before administration. The complete list of excipients is provided in the Summary of Product Characteristics (SmPC) available from the marketing authorization holder.

Frequently Asked Questions About Dridol