Nefopam Dosing Recommendations
Nefopam should be administered intravenously at 20 mg slowly over 15-20 minutes as a single dose, or via continuous infusion at 60-120 mg/day, with oral dosing at 90-180 mg daily divided into three to six doses. 1
Intravenous Administration
- Single IV dose: 20 mg administered slowly over 15-20 minutes to minimize adverse effects including nausea, cold sweating, dizziness, tachycardia, and drowsiness 1
- Continuous IV infusion: 60-120 mg/day for sustained analgesia 1
- The slow administration rate is critical to prevent acute anticholinergic and cardiovascular side effects 1
Oral Administration
- Total daily dose: 90-180 mg divided into 3-6 doses per day 1
- Individual dose range: 30-60 mg per dose based on the total daily requirement 2, 3
- Studies demonstrate that 30 mg oral doses provide statistically significant analgesia superior to placebo, while 60 mg doses show efficacy at specific time points 2
- A controlled trial using 60 mg three times daily (180 mg/day total) for three days showed distinct superiority over placebo in both initial and sustained analgesic effectiveness 3
Intramuscular Administration
- IM dose: 20 mg has been shown to be equally effective as 50 mg pethidine and statistically superior to placebo 3
- This route is effective but carries higher abuse potential, particularly with chronic use 4
Critical Safety Considerations
Abuse potential is substantial - case reports document severe dependence with doses escalating from 120 mg/day to 1840 mg/day, producing psychostimulant-like effects including violent behavior, tremor, myoclonus, and depressive withdrawal symptoms 4. The drug's triple neurotransmitter reuptake inhibition (serotonin, norepinephrine, dopamine) creates pharmacodynamic tolerance that can develop rapidly 4.
Common dose-related adverse effects include anticholinergic symptoms (dry mouth, tremor), cardiovascular effects (tachycardia), and CNS effects (dizziness, drowsiness) that necessitate slow IV administration 1, 4.
Mechanism and Clinical Context
Nefopam functions through dual mechanisms: descending pain modulation via triple neurotransmitter reuptake inhibition and inhibition of NMDA-mediated long-term potentiation through calcium channel blockade 1. This makes it particularly suitable for neuropathic pain rather than purely nociceptive pain 1.
The ceiling effect for analgesia remains uncertain and depends on the specific pain mechanism being treated 1.