It is believed to work in the brain and spinal cord to relieve pain. There it is believed to work via unique mechanisms. Firstly it increases the activity of the serotonin, norepinephrine and dopamineneurotransmitters involved in, among other things, pain signaling. Secondly, it modulates sodium and calcium channels, thereby inhibiting the release of glutamate, a key neurotransmitter involved in pain processing.
Nefopam is effective for prevention of shivering during surgery or recovery from surgery. Nefopam was significantly more effective than aspirin as an analgesic in one clinical trial, although with a greater incidence of side effects such as sweating, dizziness and nausea, especially at higher doses. The estimated relative potency of nefopam to morphine indicates that 20 mg of nefopam HCl is the approximate analgesic equal of 12 mg of morphine with comparable analgesic efficacy to morphine, or oxycodone, while Nefopam tends to produce fewer 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. Nefopam is also used to treat severe hiccups.
Nefopam is being studied as a treatment for the desmoid tumors associated with aggressive fibromatosis. Nefopam has been shown to slow or stop desmoid tumors' growth in mice during a pre-clinical phase study.
Common side effects include nausea, nervousness, dry mouth, light-headedness and urinary retention. Less common side effects include vomiting, blurred vision, drowsiness, sweating, insomnia, headache, confusion, hallucinations, tachycardia, aggravation of angina and rarely a temporary and benign pink discolouration of the skin or erythema multiforme. Overall, the incidence of side-effects are less with the oral formulation and generally transient and mild in nature.
Recreational use of nefopam has rarely been reported, and is far less common than with opioid analgesics.
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