) Betagen Topical Spray is used for the treatment of infected superficial lesions in dogs. Betagen Topical Spray contains gentamicin sulfate and betamethasone valerate. Each ml of Betagen Topical Spray contains gentamicin sulfate, USP equivalent to 0.57 mg gentamicin base, and betamethasone valerate, USP equivalent to 0.284 mg betamethasone. Recommended dosage of Betagen Topical Spray is 2 sprays administered 2 to 4 times daily for 7 days. Gentamicin sulfate and betamethasone valerate.