Nasen®: composition and pharmaceutical form
Nasen® comes as film-coated tablets; one tablet contains 10 mg of zolpidem tartrate.
That is exactly the dose regarded as the maximum daily amount for an adult. For elderly and debilitated patients and for people with impaired liver function, who should have 5 mg, the tablet is therefore split rather than taken whole.
How Nasen® works
Zolpidem is a short-acting hypnotic from the imidazopyridine group. It binds to the omega-1 receptor subtype (also known as benzodiazepine subtype 1), which is the α subunit within the GABA-A receptor complex.
The difference from benzodiazepines is fundamental: those bind non-selectively to all three omega receptor subtypes, whereas zolpidem binds selectively to omega-1. Modulation of the chloride channel through that receptor is what produces the specific hypnotic effect. At the same time zolpidem's binding site is similar to the benzodiazepine one, and its action is reversed by the benzodiazepine receptor antagonist flumazenil.
Indications
Nasen® is used for the short-term treatment of insomnia.
The wording of the indication is deliberately narrow: the medicine is prescribed only when insomnia disturbs a person's normal functioning or is extremely distressing for them. Occasional difficulty falling asleep that does not affect daytime life is not a reason for a hypnotic.
Method of use and dosage
The medicine is taken once, immediately before going to bed, and a repeat dose the same night is unacceptable. Adults are recommended 10 mg a day; the lowest effective dose should be used and 10 mg not exceeded.
| Patient | Dose before sleep |
|---|---|
| Adults under 65 | 10 mg; with good tolerance and satisfactory condition the dose may be raised within that ceiling |
| Over 65 and debilitated patients | start at 5 mg, do not exceed 10 mg |
| Hepatic impairment | 5 mg |
| Length of the course | from a few days to 2 weeks, a maximum of 4 weeks including the withdrawal period |
A separate practical condition: after taking it you need to allow yourself 8 hours of uninterrupted sleep. If the medicine is taken less than 8 hours before activities requiring a clear head, the risk of next-day impairment rises sharply, including the ability to drive.
Contraindications
The list is short, but each point is tied to a specific danger, from respiratory depression to hepatic encephalopathy.
- hypersensitivity to zolpidem or to any excipient;
- sleep apnoea syndrome;
- myasthenia gravis;
- severe hepatic impairment;
- severe respiratory failure;
- age under 18.
Special warnings and precautions
Before a hypnotic is prescribed, the causes of the insomnia should as far as possible be established and the factors that caused it removed. If after 7–14 days of use the insomnia persists or worsens, this may point to a different nature of the sleep disorder and is a reason to review the diagnosis, not to increase the dose.
Dependence and withdrawal syndrome
Prolonged use leads to a gradual weakening of the effect through the development of tolerance, and prolonged use of high doses of hypnotics leads to physical and psychological dependence. The risk grows with the dose and the length of treatment and is especially high in those who abuse alcohol or medicines. Abrupt withdrawal after long use of high doses causes a withdrawal syndrome: insomnia, headache and muscle pain, increased anxiety and tension, psychomotor agitation, confusion and irritability. In severe cases depersonalisation, derealisation, heightened perception of sounds, numbness and tingling in the limbs, increased sensitivity to light, noise and touch, hallucinations and convulsive seizures are possible. That is precisely why the length of treatment is kept to a minimum and does not go beyond 4 weeks including withdrawal.
Other warnings
- the medicine can cause anterograde amnesia, especially if 7–8 hours of sleep were not achieved after taking it;
- because of its muscle-relaxing action the risk of falls and of hip fracture rises, especially in elderly people who get up at night;
- if paradoxical reactions appear — agitation, insomnia, irritability, nightmares, hallucinations, psychosis, changes in behaviour — the medicine is withdrawn;
- in depression the minimum dose is prescribed because of the possibility of intentional overdose, and medicines of this group are not used as the sole treatment for depression or for the anxiety linked to it;
- in patients with respiratory disorders zolpidem may worsen respiratory failure;
- particular caution is needed in psychiatric illness and after detoxification courses;
- the risk of next-day impairment is higher with a dose above the recommended one and in combination with alcohol or with central nervous system depressants;
- the tablets contain lactose, so they are unsuitable in hereditary galactose intolerance, Lapp lactase deficiency and glucose-galactose malabsorption syndrome.
Drug interactions
Alcohol enhances the hypnotic effect of zolpidem and raises the likelihood of paradoxical reactions — psychomotor agitation, aggressiveness, irritability. Concomitant use with central nervous system depressants — neuroleptics, other hypnotics, anxiolytics and sedatives, antidepressants, narcotic analgesics, antiepileptics, anaesthetics and sedating antihistamines — increases drowsiness and next-day psychomotor impairment, including the ability to drive.
Isolated cases of visual hallucinations have been described when zolpidem was combined with antidepressants: bupropion, desipramine, fluoxetine, sertraline and venlafaxine. Fluvoxamine and ciprofloxacin raise the blood concentration of zolpidem, and concomitant use with them is not recommended. Medicines affecting the cytochrome P450 system change its action in both directions: erythromycin may enhance it and rifampicin weakens it. No significant interaction with ranitidine has been noted.
Pregnancy and breastfeeding
In animal studies no teratogenic or embryotoxic effect of zolpidem was detected, but sufficiently large and well-controlled observations in pregnant women have not been carried out. The medicine should not be used during pregnancy, especially in the first trimester.
If the mother took benzodiazepines or similar medicines for a long time late in pregnancy, a withdrawal syndrome or physical dependence is possible in the newborn. Use in late pregnancy or during labour may cause hypothermia, reduced muscle tone and respiratory failure in the child. Zolpidem passes into breast milk in small amounts, so the medicine is not recommended while breastfeeding.
Adverse effects
Most of the adverse reactions concern the nervous system and repeat the medicine's mechanism of action: sluggishness and impaired coordination are a continuation of the hypnotic effect, not a separate surprise.
- nervous system: dizziness, a feeling of being stunned, headache, drowsiness, anterograde amnesia, apathy, emotional lability, sleep disorders, altered taste, ataxia and an unsteady gait;
- psychiatric: nightmares, night-time restlessness;
- cardiac: palpitations, occasionally arrhythmia;
- blood: changes in the blood picture — leucopenia, agranulocytosis;
- respiratory and eyes: cough, asthma, visual disturbances;
- digestive: diarrhoea, nausea, vomiting, abdominal bloating;
- musculoskeletal: muscle spasms, arthritis;
- other: menstrual cycle disorders, reduced libido, changes in appetite and weight, increased thirst, hypersensitivity reactions in the form of rash and urticaria.
Next-day impairment is worth remembering separately. If a full eight hours of sleep did not follow the dose, attention and coordination may still be reduced in the morning, and that affects driving and operating machinery.
Overdose
Overdose of zolpidem causes disturbances of consciousness of varying degree, from drowsiness to coma. No lasting consequences were observed even at 40 times the recommended dose. Mixed poisonings, however — zolpidem with alcohol or with other central nervous system depressants — may be life-threatening.
Any overdose requires medical intervention. Help includes inducing vomiting within an hour of intake or gastric lavage if the patient is unconscious, and activated charcoal; circulation and breathing are monitored and symptomatic and supportive treatment is given. Flumazenil may be given intravenously, but it is capable of provoking neurological symptoms, including seizures. Zolpidem is not removed by haemodialysis.
How to get a prescription for Nasen® online
Nasen® is a prescription-only medicine: a hypnotic of this group is prescribed as a short course and only after the doctor has looked into the cause of the insomnia. During the online consultation the doctor will clarify the nature of the sleep disorder, assess contraindications — apnoea, respiratory and liver problems — and look at what you are already taking.
If the medicine is suitable, the doctor will issue an electronic prescription, set the length of the course and explain how to finish it so as not to run into a withdrawal syndrome.
