Nitrazepam

Debilitated patients: 2.5 mg once daily, may be increased to 5 mg once daily if needed. Doses to be taken at bedtime. Max: 5 mg daily. Use the lowest recommended dose for the shortest possible duration.

Patients with chronic pulmonary insufficiency: Dose reduction may be necessary.

Severe: Contraindicated.

May be taken with or without food.

Acute pulmonary insufficiency, respiratory depression, sleep apnoea syndrome, acute porphyria, myasthenia gravis, phobic or obsessional states, chronic psychosis. Severe hepatic impairment. Children.

Patient with depression, especially if suicidal risk may be present; history of psychiatric or personality disorders, acute alcoholism or drug abuse; hypoalbuminaemia; respiratory disease, chronic pulmonary insufficiency. Individuals at risk of falls. Elderly and debilitated patients. Renal and mild to moderate hepatic impairment.

Significant: CNS depression, anterograde amnesia, rebound insomnia (after treatment withdrawal); depression, confusional or agitational states, paradoxical reactions, including hyperactive or aggressive behaviour; hazardous sleep-related activities (e.g. sleep-driving, cooking and eating food, making phone calls while asleep); drug tolerance, psychological and physical dependence (long-term use). Rarely, anaphylaxis/anaphylactoid reactions, angioedema; bronchial hypersecretion and excessive salivation or drooling which may result in aspiration pneumonia; transient global amnesia or traveller’s amnesia (if taken for sleep induction while travelling).
Blood and lymphatic system disorders: Rarely, blood dyscrasias.
Ear and labyrinth disorders: Rarely, vertigo.
Eye disorders: Visual disturbances, double vision.
General disorders and administration site conditions: Fatigue.
Gastrointestinal disorders: Rarely, nausea, gastrointestinal upset.
Hepatobiliary disorders: Rarely, jaundice.
Musculoskeletal and connective tissue disorders: Muscle weakness.
Nervous system disorders: Dizziness, drowsiness, ataxia, headache, dysarthria, tremor.
Psychiatric disorders: Excitement, libido fluctuations, restlessness.
Renal and urinary disorders: Rarely, urinary retention.
Skin and subcutaneous tissue disorders: Rarely, rash.
Vascular disorders: Rarely, hypotension.

This drug may cause sedation, amnesia, impaired concentration and muscle function; if affected, do not drive or operate machinery. Ensure to have an uninterrupted sleep of 7-8 hours after taking a dose.

Monitor CV, respiratory and mental status.

Symptoms: Drowsiness, dysarthria, confusion, lethargy, ataxia, hypotonia, hypotension, respiratory depression and rarely coma. Management: Symptomatic and supportive treatment. Induce vomiting within 1 hour (for conscious patients) or perform gastric lavage with airway protection (for unconscious patients). May give activated charcoal if there is no advantage in stomach emptying. May consider IV flumazenil for reversing the sedative effects.

Increased risk of sedation, respiratory depression and coma when taken with opioids. Enhanced CNS depressant effects with centrally-acting agents (e.g. other hypnotics, neuroleptics, tranquilisers, antidepressants, anti-epileptics, sedative antihistamines, analgesics, anaesthetics, lofexidine, nabilone). May reduce plasma concentration with rifampicin. Increased sedative effects with moxonidine, tizanidine, and baclofen. May enhance toxic effects with hydantoins or barbiturates. Cimetidine may inhibit the metabolism of nitrazepam.

May enhance the sedative effects with alcohol.

Description:
Mechanism of Action: Nitrazepam is a benzodiazepine with sedative, hypnotic and anxiolytic properties. It binds to stereospecific benzodiazepine receptors on postsynaptic GABA neurons at several CNS sites including the reticular formation and limbic system. Increased neuronal membrane permeability to chloride ions produce an enhanced GABA inhibitory effect on neuronal excitability. This chloride ions shift leads to hyperpolarisation and stabilisation.
Onset: 30-60 minutes.
Duration: 6-8 hours.
Pharmacokinetics:
Absorption: Well absorbed from the gastrointestinal tract. Bioavailability: Approx 80%. Time to peak plasma concentration: Approx 2-3 hours.
Distribution: Crosses the blood-brain barrier and placenta; enters breast milk (small amounts). Distributed in CSF and saliva. Volume of distribution: 2.4 L/kg (range:1.6-3.2 L/kg). Plasma protein binding: Approx 87%.
Metabolism: Metabolised in the liver primarily via nitroreduction followed by acetylation.
Excretion: Via urine (mainly as free or conjugated metabolites; approx 5% as unchanged drug); faeces (14-20%). Elimination half-life: 30 hours (range: 18-57 hours).

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 4506, Nitrazepam. https://pubchem.ncbi.nlm.nih.gov/compound/Nitrazepam. Accessed Feb. 23, 2022.

Tab: Store below 25°C. Protect from light and moisture. Oral solution Store below 25°C. Protect from light. Do not freeze. Storage recommendations may vary among individual products. Refer to detailed product guideline.

Thuốc ngủ & thuốc an thần

N05CD02 - nitrazepam ; Belongs to the class of benzodiazepine derivatives. Used as hypnotics and sedatives.

Alodorm (Alphapharm). MIMS Hong Kong. http://www.mims.com/hongkong. Accessed 10/01/2022.

Anon. Nitrazepam. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 10/01/2022.

Buckingham R (ed). Nitrazepam. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. www.medicinescomplete.com. Accessed 10/01/2022.

Douglas Pharmaceuticals Ltd. Nitrados 5mg Tablet data sheet 23 May 2017. Medsafe. http://www.medsafe.govt.nz. Accessed 10/01/2022.

Joint Formulary Committee. Nitrazepam. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 10/01/2022.

Nitrazepam 5 mg Tablets (Accord-UK Ltd). MHRA. https://products.mhra.gov.uk. Accessed 10/01/2022.

Nitrazepam Mixture 2.5 mg/5 mL Oral Suspension BP (Essential Pharma). MHRA. https://products.mhra.gov.uk. Accessed 10/01/2022.