Mefenamic Acid

What Is Mefenamic Acid?

Mefenamic Acid is a nonsteroidal anti-inflammatory drug (NSAID) indicated for relief of mild to moderate pain in patients 14 years of age and older, when therapy will not exceed one week (7 days), and for treatment of primary dysmenorrhea. Mefenamic acid is available in generic form.

What Are Side Effects of Mefenamic Acid?

Common side effects of mefenamic acid include:

• abdominal pain
• constipation
• diarrhea
• indigestion
• gas
• gross bleeding/perforation
• heartburn
• nausea
• GI ulcers (gastric/duodenal)
• vomiting
• abnormal renal function
• anemia
• dizziness
• swelling
• elevated liver enzymes
• headaches
• increased bleeding time
• itching
• rashes, and
• ringing in the ears (tinnitus)

Dosage for Mefenamic Acid

For the relief of acute pain in adults and adolescents 14 years of age and older, the recommended dose of mefenamic acid is 500 mg as an initial dose followed by 250 mg every 6 hours as needed, usually not to exceed one week. For the treatment of primary dysmenorrhea, the recommended dose of mefenamic acid is 500 mg as an initial dose followed by 250 mg every 6 hours, given orally, starting with the onset of bleeding and associated symptoms.

What Drugs, Substances, or Supplements Interact with Mefenamic Acid?

Mefenamic acid may interact with anticoagulants, antiplatelet agents, selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), ACE inhibitors, angiotensin receptor blockers, beta-blockers, diuretics, digoxin, lithium, methotrexate, cyclosporine, pemetrexed, and antacids. Tell your doctor all medications and supplements you use.

Mefenamic Acid During Pregnancy and Breastfeeding

During early pregnancy, use mefenamic acid only if prescribed. Mefenamic acid is not recommended during the third trimester of pregnancy as it may harm a fetus. Mefenamic acid passes into breast milk and is not recommended for use while breastfeeding.

Additional Information

Our Mefenamic Acid Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

Get emergency medical help if you have signs of an allergic reaction (sneezing, runny or stuffy nose, hives, wheezing or trouble breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Get emergency medical help if you have signs of a heart attack or stroke: chest pain spreading to your jaw or shoulder, sudden numbness or weakness on one side of the body, slurred speech, feeling short of breath.

Stop using mefenamic acid and call your doctor at once if you have:

• shortness of breath (even with mild exertion);
• swelling or rapid weight gain;
• nausea, diarrhea, flu-like symptoms (fever, swollen glands, muscle aches, severe weakness);
• a skin rash, no matter how mild;
• signs of stomach bleeding--bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;
• liver problems--loss of appetite, stomach pain (upper right side), tiredness, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
• kidney problems--little or no urination, swelling in your feet or ankles, feeling tired or short of breath; o
• low red blood cells (anemia)--pale skin, unusual tiredness, feeling light-headed or short of breath, cold hands and feet.

Common side effects may include:

• heartburn, stomach pain, gas, nausea, vomiting;
• diarrhea, constipation; or
• dizziness.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Mefenamic Acid (Mefenamic Acid Capsules)