Posted by jrbecker on September 20, 2005, at 9:01:03
who funds this stuff? talk about confirming the obvious....
Caffeine Partially Counteracts Sedation Effects of Zolpidem (Ambien)
By Crystal PhendWASHINGTON, DC -- September 19, 2005 -- Taking the sleep aide zolpidem (Ambien) with a can of soda or coffee could reduce the drug's effectiveness, according to researchers who presented study results at the American College of Clinical Pharmacology (ACCP) here on September 11th.
A high dose of caffeine -- 500 mg or the equivalent of four cups of coffee -- reduced the effect of zolpidem by two thirds, according to subjective measures, said lead author Dora Farkas, PhD, a post-doctoral fellow, Department of Pharmacology and Experimental Therapeutics, Tufts University, Boston, Massachusetts, United States.
Although the effects of caffeine on the sedative effects of benzodiazepine agonists such as zolpidem have been theorized, the interaction was never confirmed by a controlled study.
In the double-blind study, Dr. Farkas and colleagues evaluated 12 healthy subjects who received 500 mg or 250 mg of caffeine or placebo, as well as a 7.5 mg dose of zolpidem, in a 6-way crossover design such that each person received each combination.
Observers and participants reported the level of sleepiness after taking each combination in addition to ranking other subjective measures like anxiety level. Plasma levels of the two drugs were measured. An electroencephalogram (EEG), digit substitution test and 16-item word-list memory test were also used to rate sedation.
Low and high dose caffeine partially reversed the sedation effects of zolpidem. High dose caffeine caused a 3- to 4-fold reduction in fatigue. The clearance of caffeine from plasma was reduced by zolpidem but not significantly so.
There was no significant difference in beta-EEGs with coadministration of caffeine and zolpidem. Subjective ratings indicated that patients felt more anxious as the caffeine dose increased with zolpidem.
Dr. Farkas said the pharmacokinetic interaction was smaller than expected but the pharmacodynamic effects of co-administration were greater than anticipated.
[Presentation title: Pharmacokinetic and Pharmacodynamic Interactions Between Zolpidem and Caffeine. Abstract 61]
poster:jrbecker
thread:557238
URL: http://www.dr-bob.org/babble/20050914/msgs/557238.html