A once-a-month pill to treat and prevent osteoporosis is due to go on sale, by prescription, next month.
A scientist at the Pennsylvania company that conducted research trials says the drug is the first monthly osteoporosis medication. Current drugs are taken weekly.
The Food and Drug Administration approved the drug last night.
GlaxoSmithKline and Roche are jointly promoting the drug (Boniva).
The companies estimate $44 million Americans over 50 suffer from the bone-weakening disease.
Trials by Radiant Research found that over three years the drug cut the number of new fractures of vertebrae in women with osteoporosis. It also increased bone density in those who hadn't developed the disease.
The most common side effects reported were abdominal pain, high blood pressure, upset stomach, joint pain, nausea and diarrhea.