A 'parafarmacia' is a distinct type of shop from a full 'farmacia' (pharmacy) — it sells non-prescription health items without needing the same licensing as a full pharmacy, and many stock a small but useful range of basic pet health products, including flea and tick treatments and general supplements, without requiring a full vet visit.
They're a handy backup between scheduled vet appointments for routine, non-prescription needs, though anything requiring a genuine prescription still needs to come from a vet clinic (see the Medication page).