Nonsteroidal anti-inflammatory drug (NSAID) / prostaglandin combinations are used to treat osteoarthritis and rheumatoid arthritis for people who have a high risk of stomach ulcers. These medications work by combining an NSAID to reduce pain and inflammation with a prostaglandin to protect the stomach lining from irritation and ulcers caused by the NSAID. They are available as oral tablets. An example of this combination is diclofenac / misoprostol (Arthrotec).