Accepted Answer

OK.

Well, the sedation dose for phenergan can go up to 50mg.

The usual dose is 25mg for something like nausea.

So 75 mg is a bit more than the normal.

However, one thing goes for him, in terms of having side effects from too much medication -- his weight. At 280 lbs, the amount of drug in him might be the same as half of the dose in a person of 150lbs or so.

Regardless, the adverse effects that can be seen with this medication:

low blood pressure and lightheadedness
over sedation -- lethargy

and the more rare and serious:
heart rhythm abnormalities
seizures
problems with fever and muscle rigidity (dystonia, dyskinesia, neuroleptic malignant syndrome)


So certainly -- keeping an eye on everything is important, but as I mentioned before -- because of his weight, it certainly reduces the chances of an adverse reaction from an "overdose" -- certainly this would be more concerning if a young child that weighed 50lbs took this dose.

Expert:	Dr. Mark
Pos. Feedback:	99.8 %
Accepts:
Answered:	9/28/2009

Doctor (MD)

U.S. Physician/Surgeon in Neurosurgery