Hi all 4 puppies first wormer with panacur. 2nd day 1 puppy vomitted immediately after wormer, did not give more. 3rd day 2 puppies vomited immediately after wormer. Didn't dose further either.

When it comes to 5 weeks I'm not sure what to use?? No other ill effects puppies fine, just sicked up. Measurements were correct and wormed after feeding.

Never used anything other than panacur

did you worm with or straight after food?  It should not be given on an empty stomach.

Yes wormed after food

I have very occasionally had a pup throw up, (but also had them do it when not wormed, but just greedy and then playing too hard) I don't reworm that day, but continue the other days, working  on the assumption that most of it will have got through, and what didn't will be overcome by the day after/before, or next worming before they leave.