Malaseb has chlorhexidine (antibacterial) and miconazole (anti fungal) in it. Miconazole is a prescription drug. There may be some formulations that you don't need a script for (I think dechra do a miconazole containing conditioner that might not need one, but not sure) but at the concentration/formulation that is in malaseb, you will need a script.
If you just need the antibacterial properties, biting other chlorhexidine shampoos (or even just plain hibiscrub) should be fine. If you need the antifungal then you'll need the anti fungal too.
(NB all said off the top my head, so more than happy to be proven wrong)
