Nefopam

Nefopam (marketed under the brandname Acupan) is an analgesic drug, developed in the early 1970s. It is widely used, mainly in European countries, for the relief of moderate to severe pain as an alternative to opioid analgesic drugs.

Use
Nefopam has additional action in the prevention of shivering, which may be a side effect of other drugs used in surgery.

Nefopam at a dose of 30–120 mg is significantly more effective than aspirin as an analgesic, although with a greater incidence of side effects such as sweating, dizziness and nausea, especially at higher doses.

Nefopam is around half the potency and slightly less effective as an analgesic compared to morphine, or oxycodone, but tends to produce less side effects, does not produce respiratory depression, and has much less abuse potential, and so is useful either as an alternative to opioids, or as an adjunctive treatment for use alongside opioid(s) or other analgesics.

Pharmacology
The mechanism of action of nefopam is not well understood, although inhibition of serotonin, dopamine and noradrenaline reuptake is thought to be involved in its analgesic effects,  and there may be other modes of action such as through histamine H3 receptors and glutamate.

Abuse & Overdose
Abuse of nefopam and death from overdose have both been reported, although these problems are less common with nefopam than with the opioid analgesic drugs.