Nefopam Opioids

Figure 2.13 Minor structural modifications of the antihistaminic drug diphenhydramine 39 (Figure 2.11) produced the anticholinergic drug orphenadrine 45 and the non-opioid analgesic nefopam 46.

Nefopam is a centrally acting non-opioid analgesic used for mild to moderate pain its mechanism of action is uncertain but may be due to an inhibition of serotonin, noradrenaline and dopamine reuptake. It is considered by some to act on GABA B receptors and is likely to interact with other drugs affecting these neuro transmitters,... 

Severe pain in an opioid addict presents a special problem. High-efficacy opioid may be ineffective (tolerance) or overdose may result low-efficacy opioids will not only be ineffective but may induce withdrawal symptoms, especially if they have some antagonist effect, e.g. pentazocine. This leaves as drugs of choice nonsteroidal anti-inflammatory drugs (NSAIDs), e.g. indometacin, and nefopam (which is neither opioid nor NSAID). 

Nefopam, an orphenadrine derivative, is a centrally acting non-opioid analgesic. Various adverse effects have been reported, including nausea, vomiting, epigastric pain, dizziness, drowsiness and mental confusion, hypotension, tachycardia, skin rashes, xerostomia, and urinary retention some of these may be related to its anticholinergic properties (SEDA-11, 100). Its unsatisfactory adverse effects profile was confirmed in two studies of pain control in cancer and rheumatoid arthritis (SEDA-15, 104)... 

The drugs dealt with in this section include aspirin and other salicylates, NSAIDs, opioid analgesics, and the miscellaneous analgesics, such as nefopam and paracetamol. Table 6.1 , (p.l34) contains a listing, with a further classification of the NSAIDs. 

Sensory systems - Eye Nefopam is a non-opioid analgesic whose action is spinal and supraspinal, including inhibition of dopamine, noradrenaline, and serotonin reuptake. A dose of 20mg has an analgesic action comparable with morphine 6 mg. Acute glaucoma angle closure is a rare complication of anaesthesia and multimodal analgesia. However, a case of unilateral permanent loss of vision after nefopam administration was reported. 

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