Ponstel 500 mg Capsules

Brand Name

The medication is marketed under the brand name Ponstel, a well-known label in the realm of pain management and anti-inflammatory therapy.

International Nonproprietary Name (INN)

The active ingredient in this product is identified globally as mefenamic acid, a name standardized for consistency across international pharmacological practices.

Form of Release

Ponstel is available as oral capsules, designed for convenient administration. Each capsule contains 250 mg of the active substance, typically packaged in bottles or blister packs to suit various patient dosing requirements.

Composition

Each capsule of Ponstel contains 250 mg of mefenamic acid as its primary active component. The formulation incorporates several inactive ingredients, such as lactose monohydrate, which acts as a filler, and microcrystalline cellulose, providing structural support. Additional excipients like magnesium stearate serve as lubricants to aid in manufacturing, while the capsule shell consists of gelatin, titanium dioxide, and iron oxides, imparting a distinctive color. Trace amounts of other stabilizers may be included to maintain the drug’s integrity and ensure consistent potency throughout its shelf life.

Pharmacologic Properties

Pharmacodynamics

Ponstel belongs to the nonsteroidal anti-inflammatory drug (NSAID) class, exerting its effects by inhibiting cyclooxygenase (COX) enzymes, primarily COX-1 and COX-2. This inhibition reduces the synthesis of prostaglandins, lipid compounds that mediate inflammation, pain, and fever. By lowering prostaglandin levels, the medication diminishes swelling, tenderness, and discomfort in affected tissues, while its antipyretic properties help regulate elevated body temperature. Its action is particularly effective in conditions involving prostaglandin-driven pain, such as menstrual cramps, due to its potency in uterine tissue.

The drug also modulates peripheral pain pathways, enhancing its analgesic effect beyond inflammation control. Clinical studies demonstrate its ability to reduce pain intensity by 40–60% within 1–2 hours in dysmenorrhea, outperforming placebo significantly. It does not alter underlying disease processes but provides symptomatic relief, improving daily function. This targeted mechanism supports its role in managing acute pain and inflammatory states with a distinct pharmacological profile.

Pharmacokinetics

Following oral administration, Ponstel is absorbed rapidly from the gastrointestinal tract, with peak plasma concentrations reached within 2 to 4 hours. Bioavailability is high, exceeding 90%, and food intake may slightly delay absorption without reducing overall uptake. The drug binds extensively to plasma proteins, primarily albumin, at over 90%, concentrating its distribution in the bloodstream and inflamed tissues.

Metabolism occurs in the liver via cytochrome P450 enzyme CYP2C9, converting mefenamic acid into 3-hydroxymethyl and 3-carboxyl metabolites, both inactive. The half-life ranges from 2 to 4 hours, necessitating multiple daily doses for sustained effect. Elimination is balanced, with approximately 50–60% excreted in urine as metabolites and 20–30% in feces via bile, with a small fraction unchanged. This short half-life ensures rapid clearance, minimizing accumulation with proper dosing.

Indications for Use

Ponstel is prescribed primarily for the relief of mild to moderate pain in adults and adolescents, including primary dysmenorrhea, where it reduces menstrual cramping and associated discomfort. It is also indicated for acute pain conditions, such as headaches, toothaches, or musculoskeletal injuries, offering effective analgesia when over-the-counter options fall short.

The medication is used for short-term management of inflammatory states, like postoperative pain or minor trauma, where its anti-inflammatory properties complement its pain relief. It may serve as an alternative in patients intolerant to other NSAIDs for similar indications. These applications highlight its utility in addressing acute pain and inflammation, particularly in gynecological and general pain contexts.

Contraindications

Ponstel is contraindicated in patients with known hypersensitivity to mefenamic acid or other NSAIDs, where reactions could range from mild rashes to severe anaphylaxis or asthma exacerbation. It is also prohibited in those with active gastrointestinal ulcers, bleeding, or perforation, due to its potential to aggravate these conditions.

Severe renal impairment (creatinine clearance below 30 mL/min), advanced liver disease, or a history of NSAID-induced gastrointestinal complications preclude its use. Patients with severe heart failure or a history of coronary artery bypass graft (CABG) surgery should avoid it, as should those with a history of stroke or myocardial infarction due to cardiovascular risks. Use in the third trimester of pregnancy is restricted, given potential fetal harm.

Method of Administration and Dosage

Administration Guidelines

The capsules should be taken orally, swallowed whole with water, preferably with food or milk to reduce gastric irritation. Timing with meals enhances tolerability, especially during initial doses, and splitting or crushing is not recommended to maintain consistent absorption. Adequate hydration supports administration and minimizes side effects.

Dosage for Adults and Children

For adults and adolescents over 14 with dysmenorrhea or acute pain, the typical dose of Ponstel is 500 mg initially (2 capsules), followed by 250 mg every 6 hours as needed, not exceeding 7 days or 1,500 mg daily. Pain management follows the same regimen, adjusted based on severity and response. Children under 14 are not typically prescribed this therapy, as safety and efficacy remain unestablished in younger pediatric populations.

Dose Adjustment in Specific Conditions

In mild to moderate renal impairment (creatinine clearance 30–60 mL/min), lower doses or extended intervals are advised, while severe impairment contraindicates use. Mild to moderate liver dysfunction requires caution, with severe cases prohibiting administration due to metabolism reliance. Elderly patients or those with gastrointestinal sensitivity may start at 250 mg per dose, with careful monitoring. Short-term use limits accumulation, guided by clinical needs.

Side Effects

Ponstel may trigger a variety of side effects, though many patients experience only mild reactions with proper use. Common issues include gastrointestinal discomfort, such as nausea, abdominal pain, or diarrhea, often lessened by food co-administration. Drowsiness, dizziness, or headache are also reported, typically resolving without intervention.

Less frequent effects include fluid retention, mild hypertension, or rash, reflecting prostaglandin inhibition. Rare but serious reactions, such as gastrointestinal bleeding, renal dysfunction, or severe allergic responses (e.g., angioedema), require immediate cessation and medical attention, particularly in prolonged use. Tinnitus or elevated liver enzymes may occur infrequently. Regular monitoring helps balance efficacy with safety during therapy.

Overdose

Symptoms of Overdose

Excessive intake of Ponstel may lead to nausea, vomiting, abdominal pain, and lethargy, with higher doses causing seizures, confusion, or renal impairment. Gastrointestinal irritation or metabolic acidosis are rare but possible, reflecting exaggerated NSAID effects. Symptoms typically peak within hours and subside with care.

First Aid Measures

In case of overdose, medical consultation is advised, with activated charcoal considered within 1–2 hours to limit absorption. Treatment focuses on supportive measures, such as hydration for renal protection or antacids for gastric relief. Monitoring vital signs and kidney function is key until recovery, usually within 24 hours, given the drug’s short half-life.

Drug Interactions

Effects on Other Medications

Ponstel inhibits CYP2C9 mildly, potentially increasing levels of warfarin, raising bleeding risk, or phenytoin, requiring dose adjustments. It may reduce the efficacy of antihypertensives like ACE inhibitors or diuretics by counteracting prostaglandin-mediated effects. Co-use with other NSAIDs or corticosteroids heightens gastrointestinal and renal risks, necessitating caution.

Lithium levels may rise due to reduced clearance, and methotrexate toxicity could increase with concurrent use. Patients should space administration of antacids or cholestyramine, which may bind the drug, by 1–2 hours to avoid reduced absorption.

Compatibility with Alcohol and Food

Moderate alcohol use does not directly alter efficacy but may increase gastrointestinal irritation, suggesting limited intake during therapy. Food enhances tolerability and slightly delays absorption, making it a recommended co-administration strategy, particularly for sensitive patients.

Special Precautions

Use During Pregnancy and Breastfeeding

Ponstel is Category C in the first two trimesters, with use limited to cases where benefits outweigh risks, and contraindicated in the third trimester due to risks of premature ductus arteriosus closure and prolonged labor. It passes into breast milk in small amounts, so breastfeeding mothers should avoid it or interrupt nursing during short-term use, guided by medical advice.

Women of childbearing age should use contraception during therapy and confirm non-pregnant status before starting, especially for extended regimens.

Impact on Driving and Operating Machinery

The medication may cause drowsiness or dizziness in some patients, suggesting caution with driving or machinery until tolerance is clear. Most individuals resume normal activities once adjusted, but initial doses warrant observation for sedative effects.

Considerations for Elderly and Pediatric Populations

Elderly patients tolerate Ponstel well at lower doses, with renal and gastrointestinal monitoring critical due to age-related risks. Adolescents over 14 can use adult dosing for pain, while children under 14 lack established safety data, limiting use to older age groups.