Acuten Injection: Each ml injection contains Nefopam Hydrochloride INN 20 mg.
Acuten Tablet: Each film coated tablet contains Nefopam Hydrochloride INN 30 mg.
Nefopam is a centrally acting analgesic with a rapid onset of action. The main site of action appears to be in the central nervous system both at the brain and spinal levels. In vitro experiments have shown nefopam to inhibit the re-uptake of various catecholamines (including noradrenaline, serotonin and dopamine). It is possible that the mechanism of action of nefopam is at least in part by altering the levels of these neuromodulators in the brain and at the spinal level. Nefopam is totally distinct from the other centrally acting analgesics such as morphine, codeine, pentazocine and propoxyphene. Unlike the narcotic agents, Nefopam has been shown not to cause respiratory depression. There is no evidence from pre-clinical research of habituation occurring with Nefopam. The absorption of Nefopam after oral administration or intramuscular injection is rapid with peak concentrations being reached in 1½ to 2 hours. The elimination from plasma occurs with a mean half life of 6 hours and 4 hours respectively. The medicine undergoes extensive metabolism by the liver and both unchanged medicine and metabolites are excreted principally in the urine, with approximately 6% in the faeces. Most of the dose is eliminated within 24 hours. A moderate to severe impairment of renal or hepatic function may reduce the elimination rate constant and cause some accumulation of Nefopam or its metabolites.
Route: IM / IV / Oral
Parenteral:
20 mg (1 mL) IM or slow IV repeated every 6 hours if necessary. Patient must remain lying down for 15–20 minutes post-injection.
Oral (Tablets):
MAO inhibitors increase risk of hypertensive crisis and hyperpyrexia (avoid co-administration or within 14 days); tricyclic antidepressants and anticholinergic agents potentiate antimuscarinic side effects; sympathomimetics potentiate tachycardia and arrhythmias.
Nefopam is contraindicated in patients with a history of convulsive disorders and should not be given to patients taking monoamine oxidase (MAO) inhibitors. Nefopam should not be used in the treatment of myocardial infarction. This advice is based on the lack of clinical experience for this indication.
Common: Nausea, nervousness, dry mouth, lightheadedness, urinary retention. Less Common: Vomiting, blurred vision, drowsiness, sweating, insomnia, headache, confusion, hallucinations, tachycardia, angina aggravation. Rare: Pink discoloration of urine.
Overdose
Symptoms and Signs
Nefopam toxicity is manifested by neurological symptoms (convulsions,hallucinations,agitation) and cardiovascular response (tachycardia with hyperdynamic circulation).
Treatment
Supportive treatment is suggested including gastric lavage, forced emesis and diuresis. Oral administration of activated charcoal may help prevent absorption. Convulsions and hallucinations may be controlled (e.g. with diazepam iv or pr). Beta-adrenergic blockers may be of use in controlling the cardiovascular complications.
Category C. Not recommended during pregnancy unless maternal benefit clearly outweighs fetal risk. Lactation: Nefopam is excreted in human milk; discontinue nursing or discontinue drug.
Store below 30°C in a cool, dry place. Protect from light and moisture. Keep out of reach of children.