Posted by Cam W. on April 26, 2000, at 22:06:03
In reply to Re: alcohol warnings, what reason/mechanism?, posted by Greg on April 26, 2000, at 14:59:50
Abby - There are at least 3 reasons why there are avoid alcohol warnings on certain medications:1) Alcohol's effects may be additive or enhanced by certain meds, mainly other CNS depressants, like benzodiazepines (eg. Valium). This can result in profound CNS depression, to the point of respiratory depression and death (as seen with Greg's friend). Risperdal enhances alcohols effects, thus makes you a 'cheaper drunk'. A drink or two is probably okay, but everyone has a different tolerance to alcohol so this is only a generalization. Some people need to avoid it completely when taking Risperdal.
2a) Alcohol inhibits ADH (antidiuretic hormone). ADH works in the kidney to reabsorb water back into your body and thus concentrate your urine. When you block it's effects with alcohol more water leaves your body than is taken in; hence, they dehydrating effect of alcohol (and the reason for many of the hangover symptoms). If alcohol is consumed regularily, you can pee off some of the drug in your body, reducing blood levels of the drug to below effective concentrations (this is seen commonly with lithium). This may be why alcohol intake should be limited with Zoloft. Again, one or two drinks for most people is not a problem with Zoloft, but for some it is.
2b) Along similar lines, highly fat soluble drugs which are absorbed into fat tissues and released slowly may have their blood concentrations increased with excessive alcohol (and ADH inhibition). Peeing off a lot of body water is like putting the same amount of fat soluble drug into a smaller glass of water, thus increasing the drug's concentration in the body (perhaps to toxic levels).
3) Certain drugs (eg Flagyl and Antabuse) stop the metabolism of alcohol at the acetaldehyde stage and do not allow the alchol to be fully broken down. Acetaldehyde is toxic to the body and can give you the worst hangover feeling (eg pounding head, nausea, "wishing-you-were-dead-because-you-drank-too-much-the-night-before" feeling, etc.) you have ever had. These drugs always (or should always) come with an "Avoid Alcohol" label on the bottle. It is a good idea to do so.
Hope this helps - Cam W.
poster:Cam W.
thread:31359
URL: http://www.dr-bob.org/babble/20000420/msgs/31403.html