Actions of Mefrin in details
Mefrin, an anthranilic acid derivative, is a nonsteroidal anti-inflammatory agent (NSAIA) which is structurally and pharmacologically related to meclofenamate sodium.
Mefrin has anti-inflammatory, analgesic and antipyretic actions, which appear to be associated with the inhibition of prostaglandin synthesis. Like other NSAIAs, Mefrin inhibits the synthesis of prostaglandins in body tissues by inhibiting cyclooxygenase, an enzyme that catalyzes the formation of prostaglandin precursors (endoperoxides) from arachidonic acid. Unlike most other NSAIAs, the fenamates including Mefrin in Mefrin, appear to compete with prostaglandins for binding at the prostaglandin receptor site and thus potentially affect prostaglandins that have already been formed.
The anti-inflammatory effect of Mefrin is due to inhibition of prostaglandin synthesis and release during inflammation.
The analgesic effect of Mefrin may involve central as well as peripheral mechanisms. Prostaglandins appear to sensitize pain receptors to mechanical stimulation and to other chemical mediators (eg, bradykinin, histamine). The analgesic effect of Mefrin is due to its inhibitory action on the synthesis of prostaglandins and the effects of prostaglandins that have already been formed. Furthermore, the anti-inflammatory effect of Mefrin may contribute to its analgesic effect.
Mefrin lowers body temperature in patients with fever. The antipyretic effect is most likely due to the suppression of prostaglandin synthesis in the central nervous system (probably in the hypothalamus).
How should I take Mefrin?
For safe and effective use of Mefrin, do not take more of it, do not take it more often, and do not take it for a longer time than ordered by your doctor. Taking too much of Mefrin may increase the chance of unwanted effects, especially in elderly patients.
Mefrin should come with a medication guide. Read and follow these instructions carefully. Ask your doctor if you have any questions.
To lessen stomach upset, you may take Mefrin with food unless your doctor tells you otherwise.
Dosing
The dose of Mefrin will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of Mefrin. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (capsules):
- For menstrual cramps:
- Adults and children over 14 years of age—At first, 500 milligrams (mg), then 250 mg every six hours as needed, usually for up to two to three days.
- Children up to 14 years of age—Use and dose must be determined by your doctor.
- For mild to moderate pain:
- Adults and children over 14 years of age—At first, 500 milligrams (mg), then 250 mg every six hours as needed, usually for not more than one week.
- Children up to 14 years of age—Use and dose must be determined by your doctor.
- For menstrual cramps:
Missed Dose
If you miss a dose of Mefrin, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Storage
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Mefrin administration
Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label.
If you take Mefrin for a long period of time, your doctor may want to check you on a regular basis to make sure this medication is not causing harmful effects. Do not miss any scheduled visits to your doctor.
Store Mefrin at room temperature, away from moisture, heat, and light.
Mefrin pharmacology
Pharmacodynamics
Mefrin (Mefrin) is a non-steroidal anti-inflammatory drug (NSAID) that exhibits anti-inflammatory, analgesic, and antipyretic activities in animal models. The mechanism of action of Mefrin (Mefrin), like that of other NSAIDs, is not completely understood but may be related to prostaglandin synthetase inhibition.
Pharmacokinetics
Absorption
Mefrin is rapidly absorbed after oral administration. In two 500-mg single oral dose studies, the mean extent of absorption was 30.5 mcg/hr/mL (17%CV).
Race
Pharmacokinetic differences due to race have not been identified.
Hepatic Insufficiency
Mefrin pharmacokinetics have not been studied in patients with hepatic dysfunction. As hepatic metabolism is a significant pathway of Mefrin elimination, patients with acute and chronic hepatic disease may require reduced doses of Mefrin (Mefrin) compared to patients with normal hepatic function.
Renal Insufficiency
Mefrin pharmacokinetics have not been investigated in subjects with renal insufficiency. Given that Mefrin, its metabolites and conjugates are primarily excreted by the kidneys, the potential exists for Mefrin metabolites to accumulate. Mefrin (Mefrin) should not be administered to patients with preexisting renal disease or in patients with significantly impaired renal function.
Clinical Studies
In controlled, double-blind, clinical trials, Mefrin (Mefrin) was evaluated for the treatment of primary spasmodic dysmenorrhea. The parameters used in determining efficacy included pain assessment by both patient and investigator; the need for concurrent analgesic medication; and evaluation of change in frequency and severity of symptoms characteristic of spasmodic dysmenorrhea. Patients received either Mefrin (Mefrin), 500 mg (2 capsules) as an initial dose of 250 mg every 6 hours, or placebo at onset of bleeding or of pain, whichever began first. After three menstrual cycles, patients were crossed over to the alternate treatment for an additional three cycles. Mefrin (Mefrin) was significantly superior to placebo in all parameters, and both treatments (drug and placebo) were equally tolerated.
REFERENCES
1. Neuvonen PJ, Kivisto KT: Enhancement of drug absorption by antacids. An unrecognized drug interaction. Clin Pharmacokinet. 27:120-8, Aug 1994.
2. Tall AR, Mistilits SP: Studies on Ponstan (Mefrin): I. Gastro-intestinal blood loss; II. Absorption and excretion of a new formulation. J Int Med Res (UK). 1975, 3 (3) p176-82.
3. Winder CV, Kaump DH, Glazko et al: Experimental observations of flufenamic, mefenamic, and meclofenamic acids. AnnPhys Med (Eng), Suppl p7-49.1967.
9. Champion GD, Graham GG: Pharmacokinetics of non-steroidal anti-inflammatory agents. Aust NZ J Med. 8 (Supp 1): 94-100, Jun 1978.
10. McGurk KA, Remmel RP, Hosagrahara VP, Tosh D, Burchell B: Reactivity of Mefrin 1-o- acyl glucuronide with proteins in vitro and ex vivo. Drug Metab Dispos. Aug 1996, 24 (8) p842-9.
11. Ito K, Niida Y, Sato J et al: Pharmacokinetics of Mefrin in preterm infants with patent ductus arteriosus. Acta Paediatr JPN. 36 (4): 387-91, 1994.
References
- DailyMed. "MEFENAMIC ACID: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
- NCIt. "Mefenamic Acid: NCI Thesaurus (NCIt) provides reference terminology for many systems. It covers vocabulary for clinical care, translational and basic research, and public information and administrative activities.". https://ncit.nci.nih.gov/ncitbrowser... (accessed September 17, 2018).
- EPA DSStox. "Mefenamic acid: DSSTox provides a high quality public chemistry resource for supporting improved predictive toxicology.". https://comptox.epa.gov/dashboard/ds... (accessed September 17, 2018).
Reviews
The results of a survey conducted on ndrugs.com for Mefrin are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Mefrin. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.User reports
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Information checked by Dr. Sachin Kumar, MD Pharmacology
