There are at least three methods of which I am aware -- the first is to take an anticholinergic like atropine, trihexyphenidyl, benztropine, dicycloverine, hyoscine, hyoscyamine, and the like, which is not good in hot weather. The other is that difenoxin, the 4-phenylpiperidine opioid Motofen and Lyspafen . . . it is used off-label to control excessive sweating, and ostensibly diphenoxylate and loperamide do this at lower levels and is not caused by the atropine content of Lomotil and Motofen as they have 2.5 per cent of the usual oral dose. The third is a narcotic which does not induce diaphoresis at normal doses, such as codeine. The sweating with meth could be from elevated body temperature rather than the CNS effects which can cause diaphoresis after a big dose of hydromorphone, for example -- so taking anti-pyretics, along with replentishing electrolytes may help. Paracetamol plus aspirin could do the trick.