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mefenamic acid (Ponstel)

Mefenamic acid (Ponstel). Indications: - short-term relief of mild to moderate pain - primary dysmenorrhea - gout [4] - juvenile rheumatoid arthritis [4] Dosage: 1) initial dose: 500 mg, then 2) 250 mg PO QID 3) maximum duration of therapy: 1 week Tabs: 250 mg. Pharmacokinetics: 1) 1 g oral dose yields mean plasma concentration of 10 ug/mL 2) metabolized to 3'hydroxymethyl & 3'carboxyl metabolites Adverse effects: 1) common (> 10%) - rash, dizziness, abdominal cramps, heartburn, indigestion, nausea 2) less common (1-10%) - itching, ringing in ears, fluid retention, headache, nervousness, vomiting 3) uncommon (< 1%) - congestive heart failure, hypertension, arrhythmia, epistaxis, confusion, hallucinations, aseptic meningitis, depression, peripheral neuropathy, urticaria, erythema multiforme, toxic epidermal necrolysis, Stevens-Johnson syndrome, gastritis, GI ulceration, cystitis, agranulocytosis, anemia, hemolytic anemia, bone marrow suppression, leukopenia, thrombocytopenia, hepatitis, angioedema, allergic rhinitis, toxic amblyopia, blurred vision, conjunctivitis, dry eyes, decreased hearing, polyuria, shortness of breath, polydipsia, tachycardia, hot flashes, drowsiness, insomnia, acute renal failure Drug interactions: 1) mefenamate may increase anticoagulant effect of warfarin 2) mefenamate decreases clearance & increases toxicity of: a) methotrexate b) Li+ c) digoxin Test interactions: -> may cause false psitive test for urinary bile with diazo tablet test Laboratory: 1) methods: HPLC, GC 2) laboratories with Loincs - mefenamate in specimen - mefenamate in gastric fluid - mefenamate in serum/plasma - mefenamate in urine

Interactions

drug interactions drug adverse effects of NSAIDs monitor with non steroidal anti-inflammatory agents (NSIADs)

General

non-steroidal anti-inflammatory agent (NSAID)

Properties

INHIBITS: cyclooxygenase MISC-INFO: elimination route LIVER 1/2life 3-4 HOURS elimination by hemodialysis - peritoneal dialysis - pregnancy-category C D <3rd trimester> safety in lactation -

Database Correlations

PUBCHEM correlations

References

  1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
  2. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  3. Clinical Guide to Laboratory Tests, NW Tietz (ed) 3rd ed, WB Saunders, Philadelpha 1995
  4. Deprecated Reference