Cimetidine is commonly prescribed for equine gastric ulcers, often found in foals and race horses, which are two populations with a higher risk for gastric ulcers than other horses. After a diagnosis of ulcers, cimetidine is usually prescribed for two to three weeks to give the ulcers time to heal. Studies show that ulcers may not heal if horses remain in training or experience stressful conditions.
Cimetidine is sometimes prescribed as a precaution to be used with nonsteroidal anti-inflammatory drugs, corticosteroids, and other drugs that can cause gastric ulcers. Cimetidine may also be prescribed in horses with melanomas, either alone or in combination with surgery or immunotherapy. The recommended duration of treatment is usually three months or more.