Betamethasone is a steroid medication used for various conditions including rheumatoid arthritis, lupus, dermatitis, psoriasis, asthma, allergic reactions, premature birth to accelerate lung development, Crohn's disease, and certain cancers such as leukemia. It can be taken orally, injected into muscles, or applied topically as a cream, lotion, or liquid. Serious side effects may include increased risk of infection, muscle weakness, severe allergic reactions, and psychosis. Long-term use may lead to adrenal insufficiency, and abrupt cessation after prolonged use can be dangerous. Betamethasone belongs to the class of glucocorticoid medications and is available in generic form. It was patented in 1958 and approved for medical use in the United States in 1961. Creams and ointments are listed on the World Health Organization's List of Essential Medicines. In the United States, pills and injectable solutions are more expensive than creams.

Sources:

https://www.drugs.com/monograph/betamethasone.html

https://www.drugs.com/monograph/betamethasone-topical.html

https://www.nlm.nih.gov/pubs/techbull/ja22/ja22_pubchem.html