FDA Authorizes Generic Nitenpyram Tablets for New World Screwworm Treatment in Dogs and Cats

Generic animal drug supply chains are now directly implicated in the federal response to New World screwworm, after the FDA issued an Emergency Use Authorization (EUA) on June 11, 2026, for Nitenpyram Tablets (nitenpyram) to treat NWS myiasis in dogs, puppies, cats, and kittens weighing at least two pounds and aged at least four weeks. Sponsored by Felix Pharmaceuticals Pvt. Ltd. of Ireland, this marks the first generic animal drug authorized under the NWS response framework.

The authorization brings the agency's cumulative NWS-related EUA and conditional approval count to thirteen, a figure Acting FDA Commissioner Kyle Diamantas indicated will grow as additional animal drug submissions are received. For generic drug manufacturers and QA leads monitoring expedited review timelines, the pace signals that 21 CFR Part 511 emergency pathway submissions are being processed at a materially compressed cadence compared to standard new animal drug application cycles.

Mechanistically, nitenpyram kills most NWS larvae within hours of the first oral dose; a second dose is required six hours later. The product's short-acting profile means it confers no prophylactic protection against reinfestation, a constraint that veterinary professionals and supply planners should factor into treatment protocol design and inventory modeling. Remaining larvae, live or dead, may require manual removal by trained veterinary personnel to reduce infection risk and limit further tissue damage.

FDA's Center for Veterinary Medicine Director Timothy Schell, Ph.D., framed the generic authorization explicitly in supply-chain terms, noting that generic animal drugs build domestic supply resilience and expand the veterinary drug toolkit. For plant heads managing OTC solid-dose manufacturing, the EUA's over-the-counter classification and dual tablet strengths (11.4 mg and 57 mg) indicate that scale-up and distribution readiness are immediate operational considerations, not deferred ones.

The authorization was coordinated across HHS and USDA, reflecting the whole-of-government posture the administration has adopted since NWS was detected in the continental United States. FDA stated it has spent nearly a year fast-tracking reviews in anticipation of domestic NWS arrival, a timeline that regulatory affairs leads should read as a precedent for how the agency may structure pre-positioning reviews in future zoonotic or animal health emergencies.

Detailed prescribing parameters, redosing guidance, and use in pregnant or nursing animals are covered in the EUA Fact Sheet and package insert; the Freedom of Information Summary is filed under EUA 006661.

The measurable outcome to watch is the rate at which additional generic submissions clear FDA review as NWS containment efforts continue through the remainder of 2026.

Source: FDA Press Releases RSS Feed via fda.gov, June 11, 2026.