PONSTEL

Pharmacokinetics

AbsorptionMefenamic acid 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). The bioavailability of the capsule relative to an IV dose or an oral solution has not been studied. Following a single 1-gram oral dose, mean peak plasma levels ranging from 10 to 20 mcg/mL have been reported. Peak plasma levels are attained in 2 to 4 hours and the elimination half-life approximates 2 hours. Fo...

Clinical Studies In controlled, double-blind, clinical trials, mefenamic acid 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 mefenamic acid, 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,...

ADVERSE REACTIONS The following adverse reactions are discussed in greater detail in other sections of the labeling: Cardiovascular Thrombotic Events (see Warnings ) GI Bleeding, Ulceration and Perforation (see Warnings ) Hepatotoxicity (see Warnings ) Hypertension (see Warnings ) Heart Failure and Edema (see Warnings ) Renal Toxicity and Hyperkalemia (see Warnings ) Anaphylactic Reactions (see Warnings ) Serious Skin Reactions (see Warnings ) Hematologic Toxicity (see Warnings ) Clinical Trials...

CONTRAINDICATIONS Mefenamic acid capsules are contraindicated in the following patients: Known hypersensitivity (e.g., anaphylactic reactions and serious skin reactions) to mefenamic acid or any components of the drug product (see WARNINGS ; Anaphylactic Reactions, Serious Skin Reactions ). History of asthma, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs. Severe,...

Drug Interactions See Table 2 for clinically significant drug interactions with mefenamic acid. $

Table 2Clinically Significant Drug Interactions with Mefenamic Acid Drugs That Interfere with Hemostasis Clinical Impact: Mefenamic acid and anticoagulants such as warfarin have a synergistic effect on bleeding. The concomitant use of mefenamic acid and anticoagulants have an increased risk of serio...