About Mefenamic Acid 500 mg Tablet
Mefenamic Acid 500 mg Tablet contains Mefenamic Acid 500 mg. Mefenamic acid is a non-steroidal anti-inflammatory drug (NSAID) used to relieve mild to moderate pain, including period pain. It may also be used to reduce heavy menstrual bleeding. It is taken with food, usually for a few days at a time.
Uses of Mefenamic Acid 500 mg Tablet
- Painful periods (menstrual cramps)
- Heavy menstrual bleeding
- Mild to moderate pain such as headache, toothache and muscle pain
Benefits
In period pain
It reduces the chemicals that cause cramping, so pain is eased and daily life is less disturbed.
In heavy periods
It can reduce the amount of blood lost during a period when taken as your doctor advises. See your doctor if heavy bleeding continues.
Side effects
Taking it with food can lower the chance of stomach side effects. Talk to your doctor if any side effect bothers you.
Common
- Nausea
- Indigestion or stomach pain
- Diarrhoea
- Dizziness
- Headache
Get medical help if you notice
- Diarrhoea that is severe or does not stop, or a skin rash — stop the medicine and contact your doctor
- Black or tarry stools, vomiting blood or severe stomach pain (signs of stomach bleeding) — stop and get medical help straight away
- Passing much less urine or swelling of the legs (possible kidney problems) — contact your doctor
- Chest pain, breathlessness, weakness on one side of the body or slurred speech — seek emergency care
- Allergic reaction: swelling of the face or lips, wheezing, difficulty breathing — seek emergency care
How to use
Take it exactly as your doctor prescribed. Swallow the tablet whole with water, with or after food. Use it for the shortest time needed.
How it works
It blocks enzymes that make prostaglandins, chemicals in the body that cause pain, swelling and cramping of the womb.
Safety advice
Alcohol Unsafe
Avoid alcohol. It increases the risk of stomach irritation and bleeding.
Pregnancy Unsafe
Generally avoided in pregnancy. NSAIDs must not be used in the last three months of pregnancy, as they can harm the baby. Use only if your doctor specifically advises it.
Breastfeeding Consult your doctor
Small amounts pass into breast milk. Ask your doctor before using it while breastfeeding.
Driving Caution
It can cause dizziness or drowsiness. Do not drive if you feel affected.
Kidney Caution
NSAIDs can reduce kidney function. Use only if your doctor advises it; it is not suitable in severe kidney disease.
Liver Caution
Use with caution in liver disease. It is not suitable in severe liver disease.
If you miss a dose
If you miss a dose, take it when you remember if you still need it. If it is nearly time for the next dose, skip the missed one. Do not take two doses together.
Quick tips
- Take it with food or milk.
- Stop it and see your doctor if you get diarrhoea or a rash.
- Do not take it with other painkillers like ibuprofen or aspirin unless your doctor says so.
- Tell your doctor if you have asthma, stomach ulcers, heart, kidney or bowel disease.
Substitutes
Same salts in the same strength from other makers. Only switch brands on your doctor's or pharmacist's advice; our pharmacist checks every order against the prescription.
Fact box
- Chemical class
- Anthranilic acid derivative (fenamate)
- Therapeutic class
- Pain relief / anti-inflammatory
- Action class
- Non-steroidal anti-inflammatory drug (NSAID)
- Habit forming
- No
- Prescription
- Required
Interactions with other medicines
Tell your doctor and pharmacist about every medicine, vitamin and herbal product you take.
| Medicine | What can happen |
|---|---|
| Other NSAIDs, including aspirin | Higher risk of stomach ulcers and bleeding |
| Blood thinners such as warfarin | Higher risk of bleeding |
| Blood pressure medicines and water tablets (diuretics) | Their effect may be reduced, and the risk of kidney problems may increase |
| Lithium and methotrexate | Their blood levels may rise, increasing side effects |
| Some antidepressants (SSRIs) | Higher risk of bleeding |
This page is general information to help you understand your medicine. It is not a substitute for advice from your doctor or pharmacist. Do not start, stop or change a medicine on your own.
Written by the Asthra Health Care team from the approved prescribing information (Mefenamic acid prescribing information (CDSCO-approved labelling); NICE BNF: mefenamic acid). Pharmacist review pending.