Adult: Usual dose: 20 mg, repeated 6 hourly if needed. Max: 120 mg daily. Patient must lie down during and for 15-20 minutes after administration.
Intravenous Acute pain, Postoperative pain
Adult: Usual dose: 20 mg via slow IV bolus infusion over at least 15 minutes, repeated 4 hourly if needed. Max: 120 mg daily. Patient must lie down during and for 15-20 minutes after administration.
Oral Moderate acute pain, Moderate chronic pain
Adult: For the relief of pain including postoperative, dental, musculoskeletal, acute traumatic and cancer pain: Initially, 60 mg tid. Usual dose: 30-90 mg tid, adjusted according to patient response. Elderly: Initially, 30 mg tid. Child: ≥12 years Same as adult dose.
Renal Impairment
PO:
ESRD: Dose reduction may be necessary.
Administration
May be taken with or without food. May be taken w/ meals if GI discomfort occurs.
Reconstitution
IV infusion: May be diluted in 0.9% NaCl solution or 5% dextrose in water.
Contraindications
History of convulsive disorders. IM/IV: Urinary retention linked to urinary or prostate disorders, angle-closure glaucoma. Oral: Concomitant use with MAOIs.
Special Precautions
Patient with angle-closure glaucoma, urinary retention, benign prostatic hyperplasia, CV disease or history of ischaemic heart disease. Patient concomitantly taking TCA. Not recommended for the treatment of MI. Renal and hepatic impairment. Children and elderly. Pregnancy and lactation. IM/IV: Not indicated for the treatment of chronic pain; not advisable for use in the elderly.
Adverse Reactions
Significant: Anticholinergic effects (e.g. blurred vision, xerostomia, constipation, urinary retention), sympathomimetic effects (e.g. tachycardia, exacerbation of angina); drug dependence and abuse. Rarely, transient pink discolouration of urine. Cardiac disorders: Palpitations. Gastrointestinal disorders: Nausea, vomiting, diarrhoea, abdominal pain. Immune system disorders: Angioedema, allergic reactions. Nervous system disorders: Dizziness, drowsiness, headache, paraesthesia, tremor, convulsion, lightheadedness. Psychiatric disorders: Insomnia, nervousness, confusion, hallucination. Skin and subcutaneous tissue disorders: Diaphoresis. Vascular disorders: Hypotension, syncope.
Patient Counseling Information
This drug may cause dizziness and drowsiness, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor renal and hepatic function; signs of anticholinergic effects (e.g. nausea, sweating) particularly within approx 15 minutes of administration (IM/IV).
Overdosage
Symptoms: Tachycardia with hyperdynamic circulation; agitation, hallucinations, convulsions, and coma. Management: Supportive and symptomatic treatment. Perform gastric lavage, or induce vomiting or diuresis. May administer activated charcoal to prevent absorption. May give diazepam for convulsions and hallucinations, and β-adrenergic blockers for CV complications.
Drug Interactions
May cause serotonin toxicity (including serotonin syndrome) with TCAs and SSRIs. May result in additive adverse effects with other anticholinergic or sympathomimetic agents. Potentially Fatal: May increase the risk of serotonin toxicity (including serotonin syndrome) with MAOIs.
Food Interaction
Alcohol may increase the CNS depressant effects of nefopam.
Lab Interference
May cause false-positive result with urinary screening test for opioids and benzodiazepines.
Action
Description: Mechanism of Action: Nefopam is a potent, centrally-acting, non-opioid analgesic with anticholinergic and sympathomimetic actions. Its exact mechanism is unclear; however, in vitro studies suggest that it inhibits the reuptake of norepinephrine, serotonin and dopamine. Onset: Rapid. Pharmacokinetics: Absorption: Absorbed from the gastrointestinal tract. Bioavailability: 40% (oral). Time to peak plasma concentration: Approx 1-3 hours (oral); 0.5-1 hour (IM). Distribution: Enters breast milk. Plasma protein binding: Approx 73%. Metabolism: Extensively metabolised in the liver to form desmethylnefopam, nefopam N-oxide, and N-glucuronide. Excretion: Mainly via urine (87%, <5% as unchanged drug); faeces (approx 8%). Elimination half-life: Approx 4 hours.
Chemical Structure
Storage
Tab: Store below 25°C. Solution for inj: Store below 30°C.