Mexico’s SADER Approves Merck Animal Health’s EXZOLT® 5% Pour-On (Fluralaner 50 mg/mL) for the Prevention and Treatment of New World Screwworm (Cochliomyia hominivorax) Larvae (Myiasis)
Veterinarians and cattle producers in Mexico have access to a new tool to protect cattle from New World Screwworm, helping to safeguard Mexico’s beef supply
RAHWAY, N.J., November 4, 2025 – Merck Animal Health, known as MSD Animal Health outside of the United States and Canada, a division of Merck & Co., Inc., Rahway, N.J., USA (NYSE:MRK), today announced the Secretaria de Agricultura y Desarrollo Rural (SADER) granted approval for EXZOLT™ 5% Pour-on (fluralaner 50 mg/mL) for use in Mexico. This innovative product is in the newest class of parasiticides known as isoxazolines. The pour-on solution is effective for the prevention and treatment of infestations caused by New World Screwworm (Cochliomyia hominivorax) larvae (myiasis). It was also previously approved for the treatment and control of cattle fever tick (Rhipicephalus microplus), horn fly (Haematobia irritans), and Dermatobia hominis larvae.
“The threat of New World Screwworm is an increasing concern for cattle producers across Mexico, including those located near the border with the United States, and could inflict severe economic losses across the country,” said Rick DeLuca, president, Merck Animal Health. “The approval of EXZOLT 5% Pour-on in Mexico demonstrates our commitment to delivering innovative solutions that address resistance challenges. Veterinarians and cattle producers can now access a powerful new tool to protect cattle from these serious parasites, helping to safeguard the industry’s economic future and Mexico’s beef supply.”
EXZOLT 5% Pour-on is a solution that delivers the active ingredient fluralaner through the skin to act systemically against infestations. It was granted approval based on demonstration of safety and effectiveness when administered according to label directions based on global studies conducted by Merck Animal Health in recent years, including a local trial done in Mexico by Centro Nacional de Referencia en Parasitología Animal y Tecnología Analítica (CENAPA).
“The SADER approval for EXZOLT 5% Pour-on represents an important milestone in bringing truly innovative treatments to the market,” said Holger Lehmann, DVM, PhD, vice president, pharmaceutical research & development, Merck Animal Health. “New World Screwworm can significantly affect the welfare of infested animals due to the high morbidity and mortality it can cause. EXZOLT 5% Pour-on, particularly when used as a preventative, will ensure the well-being of cattle at-risk of infestations caused by New World Screwworm larvae.”
The safety of this product in animals under 4 months of age has not been established. Topical treatment with EXZOLT Pour-on is generally well tolerated. No serious adverse reactions were reported in the studies. Mild, transient local reactions have been observed in some animals, which do not affect the animal’s general health and do not require specific treatment. If more severe reactions are observed, a veterinarian should be consulted.
Merck Animal Health is actively following all the processes set by the regulatory authorities in other countries to gain market authorization for this new product against New World Screwworm to control the spread of the disease and protect cattle.
About Merck Animal Health
At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than a century, we’ve been at the forefront of research, bringing forward medicines, vaccines and innovative health solutions for the world’s most challenging diseases. Merck Animal Health, a division of Merck & Co., Inc., Rahway, N.J., USA, is the global animal health business of Merck. Through its commitment to The Science of Healthier Animals®, Merck Animal Health offers veterinarians, farmers, producers, pet owners and governments one of the widest ranges of veterinary pharmaceuticals, vaccines and health management solutions and services as well as an extensive suite of connected technology that includes identification, traceability and monitoring products. Merck Animal Health is dedicated to preserving and improving the health, well-being and performance of animals and the people who care for them. It invests extensively in dynamic and comprehensive R&D resources and a modern, global supply chain. Merck Animal Health is present in more than 50 countries, while its products are available in some 150 markets. For more information, visit www.merck-animal-health.com and connect with us on LinkedIn, Facebook, X (formerly Twitter) and Instagram.
Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA
This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.
Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.
The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).