Tonifen (Mefenamic Acid)

Tonifen (Mefenamic Acid) Uses, Dosage, Side Effects, Food Interaction and all others data.

Tonifen (Mefenamic Acid), an anthranilic acid derivative, is a prototypical NSAID. It reversibly inhibits the cyclooxygenase-1 and cyclooxygenase-2 (COX-1 and COX-2) enzymes, thus resulting in reduced synthesis of prostaglandin precursors. It has analgesic and antipyretic properties with minor anti-inflammatory activity.

Tonifen (Mefenamic Acid), an anthranilic acid derivative, is a member of the fenamate group of nonsteroidal anti-inflammatory drugs (NSAIDs). It exhibits anti-inflammatory, analgesic, and antipyretic activities. Similar to other NSAIDs, mefenamic acid inhibits prostaglandin synthetase.

Trade Name Tonifen (Mefenamic Acid)
Generic Mefenamic acid
Mefenamic acid Other Names Acide méfénamique, ácido mefenámico, Acidum mefenamicum, Mefenamic acid, Mefenaminsäure
Type
Formula C15H15NO2
Weight Average: 241.2851
Monoisotopic: 241.110278729
Protein binding

90%

Groups Approved
Therapeutic Class Drugs for Osteoarthritis, Drugs used for Rheumatoid Arthritis, Non-steroidal Anti-inflammatory Drugs (NSAIDs)
Manufacturer
Available Country Taiwan
Last Updated: September 19, 2023 at 7:00 am
Tonifen (Mefenamic Acid)
Tonifen (Mefenamic Acid)

Uses

Tonifen (Mefenamic Acid) is used in mild to moderate pain including headache, dental pain, postoperative and postpartum pain, dysmenorrhoea, menorrhagia, in musculoskeletal and joint disorders such as osteoarthritis and rheumatoid arthritis; and in children with fever and juvenile idiopathic arthritis.

Tonifen (Mefenamic Acid) is also used to associated treatment for these conditions: Mild pain, Primary Dysmenorrhoea, Gastrointestinal cramps, Moderate Pain

How Tonifen (Mefenamic Acid) works

Tonifen (Mefenamic Acid) binds the prostaglandin synthetase receptors COX-1 and COX-2, inhibiting the action of prostaglandin synthetase. As these receptors have a role as a major mediator of inflammation and/or a role for prostanoid signaling in activity-dependent plasticity, the symptoms of pain are temporarily reduced.

Dosage

Tonifen (Mefenamic Acid) dosage

As with other NSAIDs, the lowest dose should be sought for each patient. Therefore, after observing the response to initial therapy with Tonifen (Mefenamic Acid), the dose and frequency should be adjusted to suit an individual patient's needs.Administration is by the oral route, preferably with food.

  • Adult: A 500 mg dose should be given to adults up to three times (1.5 g total) per day.
  • Infants over 6 months: 25 mg/kg of body weight daily in divided doses for not longer than 7 days.

Side Effects

In patients taking Tonifen (Mefenamic Acid) or other NSAIDs, the most frequently reported adverse experiences include : abdominal pain, constipation, diarrhoea, dyspepsia, flatulence, gross bleeding/perforation, heartburn, nausea, GI ulcers, vomiting, abnormal renal function, anaemia, dizziness, oedema, elevated liver enzymes, headache, increased bleeding time, pruritus, rash and tinnitus.

Toxicity

Oral, rat LD50: 740 mg/kg. Symptoms of overdose may include severe stomach pain, coffee ground-like vomit, dark stool, ringing in the ears, change in amount of urine, unusually fast or slow heartbeat, muscle weakness, slow or shallow breathing, confusion, severe headache or loss of consciousness.

Precaution

NSAIDs should be prescribed with extreme caution in those with a prior history of ulcer disease or gastrointestinal bleeding. To minimise the potential risk for an adverse GI event, the lowest effective dose should be used for the shortest possible duration. In cases with pre-existing advanced kidney disease, treatment with Tonifen (Mefenamic Acid) is not recommended.

Interaction

Concomitant use with CYP2C9 isoenzyme inhibitors may alter safety and efficacy of mefenamic acid. May enhance methotrexate toxicity. Reduced BP response to ACE inhibitors or angiotensin II receptor antagonists. Increased risk of serious GI events with aspirin. May reduce the natriuretic effects of furosemide or thiazide diuretics. Reduced renal lithium clearance and elevated plasma lithium levels. May enhance anticoagulant effect of warfarin.

Food Interaction

  • Avoid alcohol.
  • Take with food.

Volume of Distribution

  • 1.06 L/kg [Normal Healthy Adults (18-45 yr)]

Elimination Route

Tonifen (Mefenamic Acid) is rapidly absorbed after oral administration.

Half Life

2 hours

Clearance

  • Oral cl=21.23 L/hr [Healthy adults (18-45 yrs)]

Elimination Route

The fecal route of elimination accounts for up to 20% of the dose, mainly in the form of unconjugated 3-carboxymefenamic acid.3 The elimination half-life of mefenamic acid is approximately two hours. Tonifen (Mefenamic Acid), its metabolites and conjugates are primarily excreted by the kidneys. Both renal and hepatic excretion are significant pathways of elimination.

Pregnancy & Breastfeeding use

Pregnancy: In late pregnancy, as with other NSAIDs, Tonifen (Mefenamic Acid) should be avoided because it may cause premature closure of the ductus arteriosus. In general there are no adequate and well controlled studies in pregnant women. Tonifen (Mefenamic Acid) should be used during pregnancy only if the potential benefit justifies the potential risk to the foetus. Rated as Pregnancy Category C.

Lactation: Trace amounts of Tonifen (Mefenamic Acid) may be present in breast milk. Taking into account the importance of the drug to the mother , decision should be made whether to discontinue nursing or to discontinue the drug.

Contraindication

Tonifen (Mefenamic Acid) is contraindicated in patients with known hypersensitivity to Me Tonifen (Mefenamic Acid) acid. Tonifen (Mefenamic Acid) should not be given to patients who have experienced asthma, urticaria, or allergic type reactions after taking aspirin or other NSAIDs. Rarely fatal, anaphylactic like reactions to NSAIDs have been reported in such patients. Tonifen (Mefenamic Acid) is contraindicated in patients with active ulceration or chronic inflammation of upper gastrointestinal tract and should not be used in patients with preexisting renal disease.

Acute Overdose

Symptoms: Headache, nausea, vomiting, epigastric pain, GI bleeding. Rarely, diarrhoea, disorientation, excitation, coma, drowsiness, tinnitus, fainting, and occasionally convulsions.

Management: Symptomatic and supportive treatment. In acute overdosage, empty the stomach immediately by inducing emesis or by gastric lavage followed by admin of activated charcoal.

Storage Condition

Store between 20-25° C.

Innovators Monograph

You find simplified version here Tonifen (Mefenamic Acid)

Tonifen (Mefenamic Acid) contains Mefenamic acid see full prescribing information from innovator Tonifen (Mefenamic Acid) Monograph, Tonifen (Mefenamic Acid) MSDS, Tonifen (Mefenamic Acid) FDA label

FAQ

What is Tonifen (Mefenamic Acid) used for?

Tonifen (Mefenamic Acid) is used short-term to treat mild to moderate pain in adults and children who are at least 14 years old.

How safe is Tonifen (Mefenamic Acid)?

Tonifen (Mefenamic Acid) may increase your risk of heart problems, including heart attack, stroke, heart failure, or blood clot. These conditions can be fatal. Your risk may increase if you already have heart disease or have taken the medication for a long period of time or at high doses.

How does Tonifen (Mefenamic Acid) work?

Tonifen (Mefenamic Acid) works by stopping the body's production of a substance that causes pain, fever, and inflammation.

What are the common side effects of Tonifen (Mefenamic Acid)?

Common side effects of Tonifen (Mefenamic Acid) are include:

  • diarrhea.
  • constipation.
  • gas or bloating.
  • headache.
  • dizziness.
  • nervousness.
  • ringing in the ears

Is Tonifen (Mefenamic Acid) safe during pregnancy?

Use of Tonifen (Mefenamic Acid) during pregnancy is not advised unless prescribed by a doctor, especially if you are 30 or more weeks pregnant.

Is Tonifen (Mefenamic Acid) safe during breastfeeding?

Tonifen (Mefenamic Acid) passes into breast milk and is not recommended for use while breastfeeding.

Can I drink alcohol with Tonifen (Mefenamic Acid)?

Do not drink alcohol while taking Tonifen (Mefenamic Acid). Alcohol can increase your risk of stomach bleeding caused by Tonifen (Mefenamic Acid). Call your doctor at once if you have symptoms of bleeding in your stomach or intestines.

Can I drive after taking Tonifen (Mefenamic Acid)?

Tonifen (Mefenamic Acid) Tablets may cause drowsiness, fatigue, dizziness or may affect your vision. If you experience any of these symptoms, you should not drive or operate machinery, or perform any tasks which may require you to be alert.

When should be taken of Tonifen (Mefenamic Acid)?

Tonifen (Mefenamic Acid) is usually taken with food every 6 hours as needed for up to 1 week.

Is it safe to take Tonifen (Mefenamic Acid)?

Tonifen (Mefenamic Acid) should not be used for longer than 7 days.

How many times can I take Tonifen (Mefenamic Acid)?

Tonifen (Mefenamic Acid) take 250 mg every six hours as needed. You shouldn't take Tonifen (Mefenamic Acid) for longer than three days.

How long does Tonifen (Mefenamic Acid) take to work?

If you wait until the symptoms have worsened,Tonifen (Mefenamic Acid) may not work as well. If you are using Tonifen (Mefenamic Acid) for painful periods, take your first dose as soon as your period starts or pain begins. Usually, you will only need to take it for the first 2 to 3 days of your period.

How long does it take for Tonifen (Mefenamic Acid) to kick in?

Tonifen (Mefenamic Acid) takes between 2 - 4 hours to kick in and start easing your period pain. Each 500mg dose of Tonifen (Mefenamic Acid) kills pain for up to 8 hours, so you may need to take it two or three times a day for all-day relief.

Can I take Tonifen (Mefenamic Acid) for a long time?

Tonifen (Mefenamic Acid) should not be used for longer than 7 days. Follow your doctor's dosing instructions very carefully. If you use Tonifen (Mefenamic Acid) long-term, you may need frequent medical tests.Tonifen (Mefenamic Acid) can cause unusual results with certain medical tests.

Who should not take Tonifen (Mefenamic Acid)?

Tonifen (Mefenamic Acid) can increase your risk of fatal heart attack or stroke. Do not use Tonifen (Mefenamic Acid) just before or after heart bypass surgery .Tonifen (Mefenamic Acid) may also cause stomach or intestinal bleeding, which can be fatal.

What happens if I miss a dose on Tonifen (Mefenamic Acid)?

Take Tonifen (Mefenamic Acid) as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happen if I take too much Tonifen (Mefenamic Acid)?

If you take too much If you take too much Tonifen (Mefenamic Acid), you may experience: drowsiness, nausea,vomiting.

When can I stop taking Tonifen (Mefenamic Acid)?

If you experience any of the following symptoms, stop taking Tonifen (Mefenamic Acid) and call your doctor: stomach pain, heartburn, vomit that is bloody or looks like coffee grounds, blood in the stool, or black and tarry stools.

Can Tonifen (Mefenamic Acid) affects my heart ?

Tonifen (Mefenamic Acid) can increase your risk of fatal heart attack or stroke, especially if you use it long term or take high doses, or if you have heart disease.

*** Taking medicines without doctor's advice can cause long-term problems.
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