Meclofenamate (Meclofenamate Sodium) - Drug Interactions, Contraindications, Overdosage, etc

DRUG INTERACTIONS

1. Warfarin

Meclofenamate sodium enhances the effect of warfarin. Therefore, when meclofenamate sodium is given to a patient receiving warfarin, the dosage of warfarin should be reduced to prevent excessive prolongation of the prothrombin time.

2. Aspirin

Concurrent administration of aspirin may lower meclofenamate sodium plasma levels, possibly by competing for protein binding sites. The urinary excretion of meclofenamate sodium is unaffected by aspirin, indicating no change in meclofenamate sodium absorption. Meclofenamate sodium does not affect serum salicylate levels. Greater fecal blood loss results from concomitant administration of both drugs than from either drug alone.

3. Propoxyphene

The concurrent administration of propoxyphene hydrochloride does not affect the bioavailability of meclofenamate sodium.

4. Antacids

Concomitant administration of aluminum and magnesium hydroxides does not interfere with absorption of meclofenamate sodium.

OVERDOSAGE

The following is based on the little information available concerning overdosage with meclofenamate sodium and related compounds. After a massive overdose, CNS stimulation may be manifested by irrational behavior, marked agitation and generalized seizures. Following this phase, renal toxicity (falling urine output, rising creatinine, abnormal urinary cellular elements) may be noted with possible oliguria or anuria and azotemia. A 24 year-old male was anuric for approximately one week after ingesting an overdose of 6 to 7 grams of meclofenamate sodium. Spontaneous diuresis and recovery subsequently occurred.

Management consists of emptying the stomach by emesis or lavage and instilling an ample dose of activated charcoal into the stomach. There is some evidence that charcoal will actively absorb meclofenamate sodium, but dialysis or hemoperfusion may be less effective because of plasma protein binding. The seizures should be controlled by an appropriate anticonvulsant regimen. Attention should be directed throughout, by careful monitoring, to the preservation of vital functions and fluid-electrolyte balance. Dialysis may be required to correct serious azotemia or electrolyte imbalance.

CONTRAINDICATIONS

Meclofenamate sodium should not be used in patients who have previously exhibited hypersensitivity to it.

Because the potential exists for cross-sensitivity to aspirin or other non-steroidal anti-inflammatory drugs, meclofenamate sodium should not be given to patients in whom these drugs induce symptoms of bronchospasm, allergic rhinitis, or urticaria.