Also I posted
I read the pages in Plumb's Veterinary Drug Handbook on cimetidine, and it's a little more complex than what has been said - which is not to give with any other drugs without a two hour window. Basically - the effect of SOME drugs taken with cimetidine is ENHANCED, and the effect of some OTHER types of drugs taken with cimetidine is DIMINISHED. There is a list of these drugs in Plumb's, and there is more extensive info in Plumb's than in the NOAHcompendium, but here is a cut and paste from NOAH:
"Due to inhibition of cytochrome P-450 activity by cimetidine, the metabolism and elimination of some drugs can be reduced. Clinically relevant interactions may occur with compounds having a narrow therapeutic index, e.g. beta-blockers, calcium channel blockers, benzodiazepines, barbiturates, phenytoin, theophylline, aminophylline, warfarin and lidocaine. Doses of such drugs may need to be reduced when administered concomitantly with cimetidine. The increased gastric pH resulting from cimetidine administration may lead to reduced absorption of drugs requiring an acid medium for absorption. It is recommended that at least 2 hours should elapse between administration of cimetidine and aluminium or magnesium hydroxide, metoclopramide, digoxin or ketoconazole when possible."
Note that there is no mention of gabapentin or pregabalin type drugs in the above list. Also note that the more common problem is that drug effect is ENHANCED, not diminished. From what I've read, I don't see a problem giving gabapentin and cimetidine at the same time and it seems to be an over-generalization to say not to give ANY other drug at the same time. If I had an SM dog on these meds, I'd want to specifically read and understand where the problem is in Plumb's or another drug handbook. Also, I would consider the option of using one of the other H2 receptor antagonists such as omeprazole, ranitidine or famotidine.