Mefatin Spas

Uses

Famotidine is used for-

• Short term treatment of active duodenal ulcer and benign gastric ulcer
• Maintenance therapy for prevention of relapses of duodenal ulceration
• Gastro-oesophageal reflux disease
• Zollinger Ellison Syndrome

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.

Mefatin Spas is also used to associated treatment for these conditions: Chronic Back Pain, Duodenal Ulcer, Erosive Esophagitis, Extra-Articular Rheumatism, Gastritis, Heartburn, Helicobacter Pylori Infection, Multiple Endocrine Neoplasia, Muscle Spasms, Nonspecific Pain Post Traumatic Injury, Osteoarthritis (OA), Postoperative pain, Stress Ulcers, Zollinger-Ellison Syndrome, Active Gastric ulcer, Acute Duodenal Ulcers, Gastrointestinal ulceration, Pathological hypersecretory conditions, Symptomatic non-erosive gastroesphageal reflux diseaseMild pain, Primary Dysmenorrhoea, Gastrointestinal cramps, Moderate Pain

How Mefatin Spas works

Histamine acts as a local hormone that stimulates the acid output by parietal cells via a paracrine mechanism. Neuroendocrine cells called enterochromaffin-like (ECL) cells lie close to the parietal cells and regulate the basal secretion of histamine. Histamine release is also promoted from stimulation by acetylcholine and gastrin, a peptide hormone. Gastrin (G) cells release gastrin, which works on CCK₂ receptors on ECL cells. This action promotes the release of histamine from ECL cells. Upon release, histamine acts on H₂ receptors expressed on the basolateral membrane of parietal cells, leading to increased intracellular cAMP levels and activated proton pumps on parietal cells. Proton pump releases more protons into the stomach, thereby increasing the secretion of acid. In conditions that are associated with acid hypersecretion such as ulcers, there is a loss of regulation of acid secretion. Famotidine works on H₂ receptors and blocks the actions of histamine.

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

Mefatin Spas dosage

Duodenal ulcer: 40 mg at night for 4 to 8 weeks

Benign gastric ulcer: 40 mg at night for 4 to 8 weeks; Maintenance therapy: 20 mg at night for preventing the recurrences of duodenal ulceration

Gastro-oesophageal reflux disease: 20 mg twice daily for 6 to 12 weeks

Zollinger Ellison syndrome: The recommended starting dose is 20 mg every six hours. Dosage should then be adjusted to individual response. Doses up to 160 mg every six hours have been administered to some patients without the development of significant adverse effects.

Dosage can be administered irrespective of meals. Antacids may be given concomitantly if needed.

As with other NSAIDs, the lowest dose should be sought for each patient. Therefore, after observing the response to initial therapy with 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

Famotidine is generally well tolerated and side effects are uncommon. Dizziness, headache, constipation and diarrhoea have been reported rarely. Other side effects reported less frequently include dry mouth, nausea and/or vomiting, rash, abdominal discomfort, anorexia and fatigue.

In patients taking 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

The oral LD₅₀ is 4049 mg/kg in rats and 4686 mg/kg in mice. The subcutaneous LD₅₀ is 800 mg/kg in rats and mice. The lowest published toxic dose (TDLo) in man following oral administration is 4 mg/kg/7D.

Symptoms of overdose resemble the adverse events seen with the use of recommended doses, and they should be responded with supportive and symptomatic treatment. Any unabsorbed drug should be removed from the gastrointestinal tract, and the patient should be monitored accordingly. The use of hemodialysis to eliminate the drug from the systemic circulation is effective, but the experience of using hemodialysis in response to famotidine overdose is limited in clinical settings.

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

Dosage reduction should be considered or interval between doses should be prolonged if creatinine clearance falls to or below 30 ml/min.

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 Mefenamic acid is not recommended.

Interaction

Famotidine does not interact with the cytochrome P450 linked drug metabolising enzyme system. So, no interactions have been found in man with Warfarin, Theophylline, Phenytoin, Diazepam, Propranolol, Aminopyrine or antipyrine.

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.

Volume of Distribution

The steady-state volume of distribution ranges from 1.0 to 1.3 L/kg. Famotidine is found in breast milk; however, it is found in breast milk at the lowest concentrations compared to other H₂ receptor antagonists.

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

Elimination Route

Following oral administration, the absorption of famotidine is dose-dependent and incomplete. The oral bioavailability ranges from 40-50%, and the Cmax is reached in 1-4 hours post-dosing. While the bioavailability can be slightly increased with the intake of food and decreased by antacids, there is no clinical significance.

Mefenamic acid is rapidly absorbed after oral administration.

Half Life

The elimination half-life is about 2 to 4 hours. The half-life is expected to increase nonlinearly in patients with decreased renal function.

2 hours

Clearance

Renal clearance is 250-450 mL/min, indicating some tubular excretion. Because the renal clearance rate exceeds the glomerular filtration rate, famotidine is thought to be mainly eliminated via both glomerular filtration and renal tubular secretion.

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

Elimination Route

About 65-70% of the total administered dose of famotidine undergoes renal elimination, and 30-35% of the dose is cleared by metabolism. Following intravenous administration, about 70% of the drug is eliminated in the urine as an unchanged drug.

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. 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: There are no adequate, well controlled studies on Famotidine in pregnancy, but it is known to cross the placenta and should be prescribed only if clearly needed.

Lactation: It is not known whether Famotidine is secreted into human milk, nursing mothers should either stop nursing or stop taking the drug.

Pregnancy: In late pregnancy, as with other NSAIDs, 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. 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 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

There are no known contraindication to Famotidine. If any evidence of hypersensitivity appear, the therapy should be discontinued and consultation with physician is required.

Mefenamic acid is contraindicated in patients with known hypersensitivity to Me Mefenamic acid acid. 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. 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

Tablet: Store between 15-30° C. Concentrate for injection: Store between 2-8° C.

Store between 20-25° C.

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