A vet prescription is required for the medicine you have chosen for cats suffering from or at risk from mixed parasitic infections caused by roundworms and tapeworms of the following species roundworms nematodes tapeworms cestodes if you do not yet have a prescription then you can print out the following blank veterinary prescription form which you can ask your vet to fill in when you next visit please note that changes to legislation in 2005 means that vets must offer you a presc