Betagen Topical Spray is a prescription veterinary medication used to treat infected skin lesions in dogs. It combines two active ingredients: an antibiotic (gentamicin) that kills bacteria and a steroid (betamethasone) that reduces inflammation and itching. Each milliliter contains 0.57 mg of gentamicin and 0.284 mg of betamethasone, delivered as a convenient spray applied directly to the skin.
What Betagen Spray Is Used For
Betagen is specifically approved for treating superficial skin infections in dogs caused by bacteria that respond to gentamicin. The antibiotic component is effective against a wide range of bacterial species commonly found on canine skin, including Staphylococcus, Streptococcus, Pseudomonas, E. coli, and Proteus species. These are the bacteria most often responsible for hot spots, wound infections, and other skin problems dogs develop.
The steroid component, betamethasone valerate, tackles the other half of the problem. Infected skin lesions are typically red, swollen, and intensely itchy, which leads dogs to scratch, lick, and chew at the area, making everything worse. Betamethasone calms that inflammatory cycle, providing relief from itching and reducing redness while the antibiotic clears the infection.
Beyond skin infections, the gentamicin and betamethasone combination (sold under several brand names including Betagen, GenOne Otic, and Gentacalm) is also labeled for use in treating ear infections and anal gland infections in both dogs and cats.
How the Two Ingredients Work Together
Skin infections in dogs rarely involve bacteria alone. The infection triggers an inflammatory response that causes swelling, heat, and itching. A dog’s natural reaction to that discomfort, constant scratching and licking, damages the skin further and spreads bacteria to surrounding tissue. Treating only the infection or only the inflammation leaves half the problem unresolved.
Gentamicin works by disrupting the ability of bacteria to produce the proteins they need to survive. It’s particularly useful because it covers gram-negative bacteria like Pseudomonas, which are notoriously difficult to treat and common in moist skin folds or wounds. Betamethasone suppresses the immune system’s overreaction at the application site, reducing swelling and the urge to scratch. Together, the two ingredients break the scratch-infection cycle that keeps skin lesions from healing.
How Betagen Spray Is Applied
Betagen comes as a liquid spray, which makes it easier to apply to painful or sensitive skin compared to creams or ointments that require rubbing. Your veterinarian will provide specific instructions for how often to apply it and for how long. For topical betamethasone products generally, application ranges from one to three times daily depending on the formulation and severity of the condition.
Before spraying, the affected area should be reasonably clean. If your dog’s fur is thick around the lesion, your vet may trim or clip the hair so the spray can reach the skin directly. Matted fur or heavy coat coverage can block the medication from absorbing properly, reducing its effectiveness. Hold the spray a few inches from the skin and apply a thin, even coating over the infected area.
One practical concern is preventing your dog from licking the treated area immediately after application. Dogs are drawn to lick at irritated skin, and ingesting the medication can reduce its effectiveness on the lesion while potentially causing unwanted effects internally. An Elizabethan collar (the “cone of shame”) or a recovery suit can help keep your dog from disturbing the treated spot while the spray absorbs.
Important Safety Considerations
Because Betagen contains a steroid, it should not be used on skin infections caused by viruses or fungi. Betamethasone suppresses the local immune response, which is helpful for controlling inflammation from bacterial infections but harmful when the immune system is actively needed to fight viral or fungal invaders. Using a steroid on a viral skin condition like herpes or a fungal infection like ringworm can cause the infection to spread more rapidly. This is one reason Betagen requires a prescription: your vet needs to confirm that bacteria, not another pathogen, are responsible for the lesion.
Prolonged use of topical steroids carries its own risks. Extended application can thin the skin at the treatment site, delay wound healing, and, if enough is absorbed through the skin over time, produce systemic effects similar to steroid overuse throughout the body. These effects include increased thirst, increased urination, and changes in appetite. Following your veterinarian’s recommended treatment duration closely helps avoid these complications. If the skin lesion hasn’t improved within the expected timeframe, a follow-up visit is more appropriate than continuing to apply the spray indefinitely.
Betagen is not intended for deep wounds, puncture injuries, or infections that have spread below the skin’s surface. “Superficial lesions” means the infection is limited to the outer layers of skin. Deeper infections typically require oral or injectable antibiotics rather than topical treatment alone.
What to Expect During Treatment
Most dogs show noticeable improvement within the first few days of treatment. The itching and redness from the steroid component often improve before the infection itself fully clears, which can be misleading. Even if your dog seems more comfortable, continuing the full course of treatment as prescribed is important to ensure the bacteria are fully eliminated. Stopping an antibiotic early, even a topical one, increases the risk of the infection returning or of surviving bacteria developing resistance to the medication.
If the lesion worsens, spreads, or doesn’t improve after several days of consistent application, the infection may involve bacteria that are resistant to gentamicin, or the underlying cause may not be bacterial at all. Your veterinarian may want to perform a culture and sensitivity test, which identifies the specific bacteria involved and which antibiotics will work against them.
Storage and Handling
Store Betagen Topical Spray at controlled room temperature, away from direct sunlight and extreme heat. Keep the cap securely closed between uses. As with all veterinary medications, store it out of reach of children and pets. Check the expiration date before each use, and dispose of any remaining product once the prescribed treatment course is complete or the product has expired.