Here are a few online pet pharmacies that are well-regarded:

1. Chewy Pharmacy (chewy.com/pharmacy): Chewy is a popular online retailer for pet supplies, including medications and prescription diets. They offer a wide range of pet medications, and their website is user-friendly. They also have a team of licensed pharmacists to assist with prescription orders.
2. 1-800-PetMeds (1800petmeds.com): 1-800-PetMeds is one of the oldest and most well-established online pet pharmacies. They offer a broad selection of pet medications and health products, including prescription medications, at competitive prices.
3. PetCareRx (petcarerx.com): PetCareRx provides a variety of pet medications, supplements, and other health products for cats, dogs, and other pets. They often have discounts and promotions, and they offer a “PetPlus” membership program for additional savings.
4. VetRxDirect (vetrxdirect.com): VetRxDirect specializes in prescription medications and veterinary supplies. They have a team of licensed pharmacists to answer questions and assist with prescription orders. They cater to a variety of pet types, including dogs, cats, horses, and more.
5. Allivet (allivet.com): Allivet offers a wide range of pet medications, supplements, and supplies for various animals, including dogs, cats, horses, and livestock. They often have competitive prices and provide customer reviews for products.