Flunitrazepam - Dosage | Interactions | Effects

This article was medically reviewed by M.Pharm, Marko Tanaskovic on August 12, 2018. To read more about an author, click here.

Flunitrazepam is drug belonging to benzodiazepine class of drugs, and chemically is very similar to nitrazepam. It exhibits sedative and hypnotic effects, which is why it is used for short-term treatment of insomnia. It is only available with a prescription. Researches have shown that this drug also exhibits anticonvulsant and anxiolytic effect, but is not used for these therapeutic purposes. Like other benzodiazepines, Flunitrazepam also acts as a muscle relaxant.

The mechanism of action is based on increasing the concentration and affinity of gamma-amino-butyric acid (GABA) that is considered to be main inhibitory neurotransmitter. GABA binding for its receptors results in the opening of chloride channels, which causes cell hyperpolarization and reduced excitation of the cells.

Flunitrazepam has not been approved by the FDA for use in the United States, but UK and AU approved the use of this medicine.


Since it exhibits a relaxing effect on the muscles, Flunitrazepam is contraindicated in patients with myasthenia gravis.

All benzodiazepines, including Flunitrazepam, may cause respiratory depression, and patients with obstructive respiratory tract diseases or other respiratory problems must not use this medicine.

Its use is contraindicated in patients suffering from sleep apnea syndrome (involuntary pause in breathing during sleep) as well as in patients who have severe hepatic impairment.

Due to the lack of data on its administration in patients under the age of 18, its use is contraindicated in these patients.

Cases of performing complex behavioral actions (preparation of meals and eating them, conducting telephone conversations and even driving motor vehicles) have been reported in patients who were not fully awake after taking this medicine. Patients usually do not remember these events (anterograde amnesia). Therefore, patients should be instructed not to drive motor vehicles operate machinery while using Flunitrazepam.

It must be used cautiously in patients with hypotension (low blood pressure), blood disorders, glaucoma, depression, schizophrenia, psychosis, or epilepsy.

Flunitrazepam is intended only for short-term treatment of insomnia (not more than a few nights) because long-term administration can cause dependence and tolerance.

Flunitrazepam, Pregnancy and Breastfeeding

AU TGA places this drug in pregnancy category C because animal studies have shown that it can cause respiratory depression and hypothermia in newborns. Withdrawal symptoms can occur in newborns whose mothers used this medication over a long period of time. The use of Flunitrazepam tablets during pregnancy should be avoided.

Flunitrazepam passes into breast milk and its use must be avoided in lactating women.


The usual dose in patients aged 18-60 years is 1-2 mg just before bed. The usual dose in patients above the age of 60 is 0.5-1 mg right before bed.

Your doctor will determine the appropriate dosing schedule for you.

If this medicine is administered over a long period of time, then stopping the therapy must be done gradually (usually during 4 weeks to 4 months) as advised by your doctor. If therapy is stopped suddenly, withdrawal symptoms can occur (e.g. worsening of insomnia, headache, anxiety, panic attacks, irritability, and others).


Flunitrazepam should not be administered concurrently with the following medicines:

  • Carbamazepine, valproic acid, lamotrigine, phenytoin and other anticonvulsant drugs.
  • Morphine, fentanyl, hydrocodone, alfentanyl, oxycodone and other opioid medicines. Simultaneous administration increases the risk of dependence.
  • Other benzodiazepines, such as:
    • alprazolam
    • midazolam
    • bromazepam
    • nitrazepam
    • lorazepam
    Simultaneous administration may potentiate sedation and lead to adverse effects.
  • Tricyclic antidepressants, such as: amitriptyline, imipramine, nortriptyline, and desimipramine. Simultaneous administration increases the risk of adverse effects.
  • Tetracyclic antidepressants, such as: amoxapine, loxapine, mirtazapine, mianserin, and maprotiline. Simultaneous administration increases the risk of adverse effects.
  • Cimetidine (a medicine used to treat conditions caused by hypersecretion of gastric acid). Cimetidine may increase the concentration of Flunitrazepam in the blood, thereby increasing the risk of adverse effects.
  • Disulfiram (a medicine used for the treatment of chronic alcoholism). Disulfiram may increase the concentration of Flunitrazepam in the blood, thereby increasing the risk of adverse effects.
  • Aprepitant (a medicine used to treat chemotherapy-induced nausea). Aprepitant may increase the concentration of Flunitrazepam in the blood, thereby increasing the risk of side effects.
  • Amiodarone (antiarrhythmic). Amiodarone slows down the metabolism of Flunitrazepam, which increases its concentration and, therefore, the risk of side effects.
  • Aripiprazole.
  • Azithromycin and erythromycin (antibiotics). These drugs slow down the metabolism of Flunitrazepam, which increases its concentration and, therefore, the risk of side effects.

Side effects

Flunitrazepam may cause the following side effects:

  • Dry mouth
  • Urinary incontinence
  • Anxiety
  • Double vision
  • Reduced libido
  • Hypotension
  • Rapid heart rate
  • Angioedema


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