FDA approves first animal drug for Giardia duodenalis, additional drugs for cows, swine

The Food and Drug Administration (FDA) has recently approved a number of animal drugs, including those that treat Giardia duodenalis in dogs and bacterial enteritis in replacement beef and dairy heifers.

Ayradia for dogs

On October 11, the FDA approved Ayradia, metronidazole oral suspension, for the treatment of Giardia duodenalis infection in dogs. Ayradia is the first FDA-approved animal drug for treating Giardia duodenalis infections.

Ayradia is available by prescription from a licensed veterinarian and administered orally at 25 mg/kg (11.3 mg/lb) of body weight, using the supplied syringe, twice daily for five consecutive days. It is supplied in 30 mL and 100 mL bottles.

Metronidazole is an antimicrobial drug that has both antibacterial and antiprotozoal activities. Veterinarians have historically prescribed a metronidazole product intended for humans when treating their animal patients for Giardia duodenalis. The approval of Ayradia means there is now a safe and effective product for this species that is manufactured to quality standards, the FDA says.

Ayradia is sponsored by Virbac Animal Health, based in Fort Worth, Texas.

Virbac Animal Health conducted a laboratory study and a field study to demonstrate the effectiveness of Ayradia to treat Giardia infections. In both studies, Ayradia effectively reduced the post-treatment counts of the Giardia parasite in treated dogs.

The most common adverse events in dogs treated with Ayradia were vomiting and diarrhea, which resolved without treatment.

Aivlosin for female swine

On October 13, the FDA approved Aivlosin Water Soluble Granules (WSG)—62.5% w/w tylvalosin as tylvalosin tartrate—for female swine intended for breeding, such as replacement gilts, gestating replacement gilts, gestating sows, lactating sows, and weaned sows.

Aivlosin is an antimicrobial drug, available by prescription from a licensed veterinarian, that is administered continuously at 50 ppm tylvalosin in drinking water for five consecutive days. It is available in 160 g and 400 g sachets.

The drug is approved for the control of porcine proliferative enteropathy associated with Lawsonia intracellularis infection and control of swine respiratory disease (SRD) indications associated with Bordetella bronchiseptica, Glaesserella (Haemophilus) parasuis, Pasteurella multocida, Streptococcus suis, and Mycoplasma hyopneumoniae in groups of swine intended for slaughter and female swine intended for breeding in buildings experiencing an outbreak of SRD.

Prior to this approval, the label indication restricted Aivlosin WSG to be used only in the drinking water of swine intended for slaughter. The drug remains not available for use in male swine intended for breeding.

Aivlosin is sponsored by ECO Animal Health Group, based in Princeton, New Jersey, and sold by Pharmgate Animal Health.

Estroplan for dairy cows

On September 20, the FDA approved Estroplan, an injectable cloprostenol solution for dairy cows. This supplement is indicated for use with gonadorelin to synchronize estrous cycles to allow for fixed time artificial insemination in lactating dairy cows.

Estroplan is available by prescription from a licensed veterinarian and is supplied in 20 mL and 100 mL multidose vials.

Estroplan is sponsored by Parnell Technologies, based in New South Wales, Australia.

A version of this story appears in the January 2024 print issue of JAVMA