Mefenamic acid is a prescription pain relief drug. It is most commonly used for short-term relief of menstrual pain, which can include migraine headaches that begin during the premenstrual period. Some doctors may also prescribe it for treatment of arthritis pain. The drug is in the non-steroidal anti-inflammatory (NSAID) class of medications, which includes drugs such as aspirin, naproxen, and ibuprofen. It is marketed under the product name Ponstel®.

This medication comes in capsule form. It is formulated to be taken approximately every six hours. Mefenamic acid is often prescribed for temporary pain relief for a week or less. When used to treat menstrual pain, it can be taken either before or during the cycle and is usually stopped once menstrual flow has subsided. If the drug is prescribed for a longer period, a doctor will typically observe the patient carefully in order to ensure that the patient is not developing an adverse reaction.

Mefenamic acid treats pain by reducing hormones that cause inflammation. For women who are menstruating, it can also slow the contractions of the uterus. It can also help to fight fever related to inflammation. The drug is believed to work by stopping the synthesis of prostaglandin, which affects the smooth contraction of the muscles.

There are several previous or current conditions which can make taking mefenamic acid too risky for a patient, or at least require special dosage or careful observation by a doctor during treatment. These include kidney, heart, or liver disease. Asthma, polyps in the nose, and smoking can all be problematic as well. A history of stroke, blood clot, or heart attack may also increase the risk of taking the drug.

The mild side effects of taking mefenamic acid need only be discussed with a doctor if they persist or become more severe. They include nervousness, headache, ringing in the ears, and dizziness. Some patients may also have constipation, diarrhea, or excessive gas and bloating.

Severe side effects of taking mefenamic acid should be reported to a doctor as soon as possible. They include fever, pale skin, and excessive tiredness or lack of energy. Some patients also experience a decrease in appetite, nausea, or uncharacteristic weight gain. There may also be problems with urination, including pain or cloudy, bloody urine. Signs of an allergic reaction, which include hives, itching, breathing problems, and swelling in the areas from the neck up, should receive emergency medical attention.