Darren,
I investigated this one a while ago. The only advice that I was given was not to dive within the first month of taking Larium. Once you are sure that the drug is having no adverse effects upon you (other than the usual nightmares, mood swings, forgetfulness etc) then it is OK to dive.
I di a fair amount of diving in the 9 months that I was taking Larium and had no problems other than forgetting half of what went on!
