
Panacur is licensed for use in pregnancy where administering all through the last trimester should reduce transference to pups by 98%. It's the only one licensed for this purpose.
For pups and after whelping it's personal choice.
The Drontal for puppies is not the same as for adults, as it only covers the roundworms, so similar to the Panacur.
Some breeders have had issues with one or other product.
IN the end these are strong chemicals, so always a chance for some reactions to occur..
AS I use Panacur on my in whelp bitches I don't worm the pups until 3 weeks then again at 7 weeks before they go to new homes when I advise worming at 11 weeks so they are done in between vaccinations.