Natriumoxibat Kalceks (Sodium Oxybate)

What Is Natriumoxibat Kalceks and What Is It Used For?

Natriumoxibat Kalceks contains sodium oxybate, a central nervous system depressant that consolidates nighttime sleep to treat narcolepsy with cataplexy in adults. It reduces excessive daytime sleepiness, cataplexy attacks (sudden episodes of muscle weakness), sleep paralysis, and hallucinations associated with narcolepsy.

Sodium oxybate is the sodium salt of gamma-hydroxybutyric acid (GHB), a naturally occurring substance found in the brain. When taken at therapeutic doses, it promotes deep, restorative sleep by acting primarily through GABA-B receptors. The exact mechanism by which it improves narcolepsy symptoms is not fully understood, but clinical evidence strongly supports its role in consolidating fragmented nighttime sleep, which in turn reduces the burden of daytime symptoms.

Narcolepsy is a chronic neurological disorder that affects the brain's ability to regulate the sleep-wake cycle. People with narcolepsy experience excessive daytime sleepiness and may have sudden, irresistible sleep attacks during the day. When narcolepsy occurs with cataplexy, patients also experience episodes of sudden muscle weakness or paralysis triggered by strong emotions such as laughter, surprise, anger, or excitement. These cataplexy attacks can range from barely noticeable muscle weakness in the jaw or knees to complete physical collapse.

In addition to cataplexy and excessive sleepiness, narcolepsy may cause sleep paralysis (a temporary inability to move when falling asleep or waking up), hypnagogic and hypnopompic hallucinations (vivid, dream-like experiences at sleep onset or waking), and severely disrupted nighttime sleep. Sodium oxybate is one of the few medications approved to address the full spectrum of narcolepsy symptoms, making it a cornerstone therapy as recommended by the American Academy of Sleep Medicine (AASM) and the European Academy of Neurology (EAN).

Natriumoxibat Kalceks is manufactured by AS KALCEKS in Latvia and is approved throughout the European Economic Area (EEA). It is available as a 180 ml bottle of oral solution at a concentration of 500 mg/ml, packaged with a calibrated dosing syringe and two child-resistant dosing cups. The medication is marketed under various names across Europe, including Sodium oxybate Kalceks, Oxybate Kalceks, and Nartex.

What Should You Know Before Taking Natriumoxibat Kalceks?

Before starting sodium oxybate, your doctor must assess you for contraindications including succinic semialdehyde dehydrogenase deficiency, major depression, and concurrent use of opioids or barbiturates. You should disclose any history of substance abuse, respiratory problems, heart failure, or liver or kidney disease.

Contraindications

You must not take Natriumoxibat Kalceks if any of the following apply:

• Allergy to sodium oxybate or any of the other ingredients in the medicine (malic acid, sodium hydroxide, purified water)
• Succinic semialdehyde dehydrogenase (SSADH) deficiency – a rare inherited metabolic disorder that impairs the body's ability to break down GHB naturally
• Major depressive disorder – sodium oxybate can worsen depression and has been associated with suicidal thoughts in some patients
• Concurrent use of opioids or barbiturates – the combination can cause life-threatening respiratory depression, profound sedation, and coma

Warnings and Precautions

Talk to your doctor or pharmacist before taking sodium oxybate if you have or have had any of the following conditions, as your treatment may require special monitoring or dose adjustment:

• Breathing or lung problems: Sodium oxybate can cause respiratory depression, particularly in overweight patients or those with pre-existing respiratory conditions such as sleep apnoea, chronic obstructive pulmonary disease (COPD), or obesity hypoventilation syndrome. Your doctor may need to monitor your breathing during treatment.
• Depression or a history of depression: This medication may worsen depressive symptoms or trigger suicidal thoughts. Report any changes in mood, behaviour, or thoughts immediately to your healthcare provider.
• Heart failure or high blood pressure: Sodium oxybate contains a significant amount of sodium (0.41 g per 2.25 g dose, equivalent to 20% of the recommended daily sodium intake). Patients on sodium-restricted diets or with cardiovascular conditions need careful consideration.
• Liver disease: The starting dose must be halved in patients with hepatic impairment, as the liver metabolises sodium oxybate. Dose increases should be made more gradually.
• Kidney disease: Patients with renal impairment should consider reducing their overall dietary sodium intake while taking this medication.
• History of substance abuse: There is a well-recognised risk of misuse and dependency. Cases of dependence have occurred after illicit use of sodium oxybate. Your doctor will assess your risk before prescribing and will monitor you throughout treatment.
• Epilepsy: Sodium oxybate is not recommended for patients with epilepsy, as it may affect seizure thresholds.
• Porphyria: This medication is not suitable for patients with this rare metabolic condition.

During treatment, immediately inform your doctor if you experience bedwetting, faecal incontinence, confusion, hallucinations, sleepwalking, or abnormal thoughts. While these effects are uncommon, they should be reported promptly. They are usually mild to moderate when they occur.

Elderly patients require closer monitoring, as the effects of sodium oxybate may be more pronounced in this age group. Your doctor will assess whether the medication is achieving the desired therapeutic effects.

Pregnancy and Breastfeeding

If you are pregnant, breastfeeding, think you may be pregnant, or are planning to have a baby, talk to your doctor before taking sodium oxybate.

Pregnancy: Very limited data exist on the use of sodium oxybate during pregnancy, and some cases of miscarriage have been reported. The potential risk is unknown, and therefore sodium oxybate is not recommended for pregnant women or women planning to become pregnant. Effective contraception should be used during treatment.

Breastfeeding: Sodium oxybate is excreted into breast milk. Changes in sleep patterns have been observed in breastfed infants whose mothers were exposed to sodium oxybate. Women taking this medication should not breastfeed.

Driving and Operating Machinery

Sodium oxybate significantly impairs your ability to drive or operate machinery. You must not drive, use machines, or perform any hazardous activity for at least six hours after taking a dose. When first starting treatment, exercise extreme caution during all activities requiring mental alertness until you know how the medication affects your next-day functioning.

Sodium Content

This medicine contains 0.41 g of sodium (the main component of cooking/table salt) in each 2.25 g dose. This is equivalent to 20% of the maximum recommended daily dietary sodium intake for an adult. Talk to your doctor or pharmacist if you need to take Natriumoxibat Kalceks daily for a prolonged period, especially if you have been advised to follow a low-sodium diet.

How Does Natriumoxibat Kalceks Interact with Other Drugs?

Sodium oxybate must never be combined with opioids, barbiturates, or alcohol. It should not be used with other CNS depressants or sedative-hypnotics. Valproate requires a dose reduction of sodium oxybate. Always inform your doctor of all medications you take, including over-the-counter drugs and supplements.

Sodium oxybate is metabolised primarily through oxidation via the enzyme GHB dehydrogenase in the liver. Because it undergoes minimal hepatic cytochrome P450 metabolism, it has fewer pharmacokinetic interactions than many other drugs. However, its pharmacodynamic interactions – particularly with other CNS depressants – can be dangerous or even fatal. The additive sedative effects of combining sodium oxybate with other depressant substances can lead to profound unconsciousness, respiratory depression, and death.

Major Interactions (Contraindicated or Avoid)

Important Interactions (Dose Adjustment Required)

It is essential that you tell your doctor or pharmacist about all medicines you are taking, have recently taken, or might take. This includes prescription medications, over-the-counter drugs, herbal preparations, and dietary supplements. Some interactions may not be immediately apparent but can develop over time with continued use.

What Is the Correct Dosage of Natriumoxibat Kalceks?

The recommended starting dose is 4.5 g/day, divided into two equal nightly doses of 2.25 g. The dose can be gradually increased to a maximum of 9 g/day. Patients taking valproate start at a reduced dose of 3.6 g/day. The first dose is taken at bedtime and the second 2.5-4 hours later.

Always take this medicine exactly as your doctor or pharmacist has told you. The dose is carefully individualised based on your response and tolerance. Your doctor will typically start with the lowest effective dose and increase it gradually at intervals of one to two weeks until the optimal balance of symptom control and tolerability is achieved.

Adults

How to Prepare and Take Each Dose

Sodium oxybate requires careful preparation before each use. The medication comes with a bottle, a calibrated dosing syringe (graduated from 1.5 g to 4.5 g), and two child-resistant dosing cups. Follow these steps each night:

1. Prepare the bottle: Remove the bottle cap by pushing down and turning counter-clockwise. On first use, press the bottle adapter firmly into the bottle neck. The adapter remains in place for subsequent uses.
2. Draw up the dose: Insert the dosing syringe tip into the centre opening and push firmly. Invert the bottle and pull the plunger down to the prescribed dose marking.
3. Prepare both cups: Return the bottle upright, remove the syringe, and empty the dose into the first dosing cup. Repeat for the second cup. Add approximately 60 ml of water (about four tablespoons) to each cup.
4. Secure the cups: Twist the child-resistant lids clockwise until they click into the locked position. Rinse the syringe with water.
5. Take the first dose: Place the second dose on your bedside table. Set an alarm for 2.5-4 hours later if needed. Sit up in bed, drink the entire first dose, replace the lid, and lie down immediately.
6. Take the second dose: When you wake (or when your alarm goes off) 2.5-4 hours later, sit up, drink the entire second dose, and lie down immediately to continue sleeping.

Both doses must be prepared before bedtime and used within 24 hours of preparation. Take your doses at consistent times each night, ideally 2-3 hours after your last meal, as food reduces absorption.

Missed Dose

If you forget to take the first dose, take it as soon as you remember, then continue as usual. If you miss the second dose, skip it entirely and do not take sodium oxybate again until the following night. Never take a double dose to make up for a missed one.

Overdose

Stopping Treatment

Continue taking sodium oxybate for as long as your doctor instructs. Do not stop abruptly, as this may cause withdrawal symptoms including return of cataplexy attacks, insomnia, headache, anxiety, dizziness, sleep disturbances, drowsiness, hallucinations, and abnormal thoughts. If you have not taken sodium oxybate for more than 14 consecutive days, contact your doctor before restarting, as you will likely need to resume at a reduced dose.

What Are the Side Effects of Natriumoxibat Kalceks?

The most common side effects are nausea, dizziness, and headache, affecting more than 1 in 10 patients. Common side effects include insomnia, blurred vision, vomiting, abdominal pain, weight loss, sleepwalking, depression, and tremor. Most side effects are mild to moderate and often improve as your body adjusts to the medication.

Like all medicines, sodium oxybate can cause side effects, although not everybody gets them. The side effects are generally mild to moderate in severity. If you experience any of the effects listed below, inform your doctor promptly, especially if they persist or worsen.

If you experience any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed above. You can also report side effects directly to your national medicines regulatory authority (e.g., the FDA in the United States, the MHRA in the United Kingdom, or the EMA in the European Union). By reporting side effects, you help provide more information on the safety of this medicine.

How Should You Store Natriumoxibat Kalceks?

No special storage conditions are required for the unopened bottle. After opening, use the contents within 90 days. Once diluted in the dosing cups, the solution must be used within 24 hours. Always store out of sight and reach of children.

Keep this medicine out of the sight and reach of children. Due to the controlled nature of sodium oxybate and its potential for misuse, take particular care to store it securely in a location that is not accessible to others, especially children and adolescents.

• Before opening: No special storage conditions required. Do not use after the expiry date stated on the carton and bottle after "EXP". The expiry date refers to the last day of that month.
• After opening: Use the contents of the bottle within 90 days. Discard any remaining solution after this period.
• After dilution: Once prepared in the dosing cups with water, the solution should be used within 24 hours.
• Disposal: Do not throw away via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer use. This helps protect the environment.

What Does Natriumoxibat Kalceks Contain?

Each millilitre of Natriumoxibat Kalceks contains 500 mg of sodium oxybate as the active ingredient. The other ingredients are malic acid (for pH adjustment), sodium hydroxide (for pH adjustment), and purified water.

Natriumoxibat Kalceks is a clear to slightly opalescent, colourless to yellowish solution. It comes in a 200 ml amber plastic bottle containing 180 ml of solution, closed with a child-resistant and tamper-evident cap. Each carton includes one bottle, a press-in bottle adapter, a graduated dosing syringe (calibrated from 1.5 g to 4.5 g), and two dosing cups with child-resistant screw caps.