FDA grants emergency approval for over-the-counter drug to treat screwworm in pets

June 11 (Reuters) – The U.S. Food and Drug Administration on Thursday authorized the emergency use of a generic over-the-counter tablet to treat infestations caused by the New World screwworm in dogs and cats, as the government steps up efforts to contain the parasite.

U.S. officials this month confirmed the first domestic cases of the parasite in more than six decades in cattle, a goat and a dog in Texas and New Mexico.

New World screwworm is a fly whose larvae feed on living tissue, entering animals through open wounds and burrowing into the flesh. 

The agency said nitenpyram tablets, a fast-acting treatment, can be used in pets weighing at least two pounds and at least four weeks old, adding that the drug is expected to help kill most larvae within hours of the first dose.

A second dose should be given six hours after the first, the agency said, but added that the drug may not protect against reinfestation and veterinarians may still need to remove remaining larvae and treat wounds.

U.S. officials have warned that while most pets in the country face low risk, animals that have recently been in affected areas were more vulnerable.

The tablets, available in two dosage strengths, are the first generic animal drug cleared under an emergency pathway for this use. 

Officials said the move was part of a broader push by U.S. health and agriculture agencies to limit the spread of the parasite and ensure pet owners have access to affordable treatment options. 

The benefits of the treatment outweigh potential risks based on available evidence, the FDA said. 

(Reporting by Sahil Pandey in Bengaluru; Editing by Jonathan Ananda)