A tourist guide I was listening to today said something like "They drug his body ..." (she was talking about the desecration of graves and buried bones during either Henry VIII's time, or Oliver Cromwell's - or both, I forget exactly now). The guide had a North American accent. It was quite obvious from the context that she meant 'dragged', but I had never heard the past tense form 'drug' before. However, it is given in the OED, which says:
"drug also occurs as a past tense and past participle form of drag v. in nonstandard and regional use (especially U.S. regional (southern and Midland)); drugged is also sometimes found in U.S. use."
Moreover, there is another entry in the OED for the verb drug, defined as "to pull forcibly, to drag". This verb is described as being a Scottish or southern English regional form. Drug is also listed as a form of the past participle. Although the first two citations are dated a1250 (a = ante ie before) and c1405 (c = circa ie about), the OED says it cannot be sure whether the verb drug or drudge was intended, as both were spelled drugge in earlier times.