Idrocilamide

The pharmacokinetics of caffeine is greatly altered by concomitant administration of the myorelaxant, idrocilamide, which inhibits the biotransformation of caffeine and prolongs its half-life nine-fold (SEDA-5, 7). Consequently, when idrocilamide is prescribed, partial... 

Oral idrocilamide reduces the clearance of caffeine, which can lead to caffeine toxicity. 

The possibility that caffeine ingestion might have had some part to play in the development of psyehiatrie disorders seen in patients taking idrocilamide, prompted a pharmaeokinetie study in 4 healthy subjects. While taking oral idrocilamide 400 mg three times a day the half-life of caffeine (150 to 200 mg of caffeine from one eup of coffee) was prolonged from about 7 to 59 hours. The overall elearanee of caffeine was decreased by about 90%. ... 

Idrocilamide ean inhibit the cytoehrome P450 isoenzyme CYP1A2 by whieh eaffeine is metabolised, leading to its aeeumulation. 

Brazier JL, Descotes J, Lery N, Ollagnier M, Evreux J-C. Inhibition by idrocilamide of the disposition of caffeine. EurJ CUn Pharmacol (1980) 17, 37-43. 

Idrocilamide given orally can increase serum theophylline levels. 

In 6 healthy subjects oral idrocilamide 600 mg daily for 3 days then 1.2 g for 4 days increased the half-life of a single dose of theophylline 2.5-fold, from 8.5 to 21.6 hours, and reduced the clearance by 67%. This is due to a reduction in the liver metabolism caused by the idrocilamide (see also Caffeine + Idrocilamide , p.ll65). Information is very limited but it indicates that concurrent use should be closely monitored. Anticipate the need to reduce the theophylline dosage with oral idrocilamide. 

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