Meprobamate

Since the effects of meprobamate and alcohol or meprobamate and other CNS depressants or psychotropic drugs may be additive, appropriate caution should be exercised with patients who take more than one of these agents simultaneously.

Meprobamate is metabolized in the liver and excreted by the kidney; to avoid its excess accumulation, caution should be exercised in administration to patients with compromised liver or kidney function.

Careful supervision of dose and amounts prescribed is advised, as well as avoidance of prolonged administration, especially for alcoholics and other patients with a known propensity for taking excessive quantities of drugs.

Meprobamate occasionally may precipitate seizures in epileptic patients.

An increased risk of congenital malformations associated with the use of minor tranquilizers (meprobamate, chlordiazepoxide and diazepam) during the first trimester of pregnancy has been suggested in several studies. Because use of these drugs is rarely a matter of urgency, their use during this period should almost always be avoided. The possibility that a woman of childbearing potential may be pregnant at the time of institution of therapy should be considered. Patients should be advised that if they become pregnant during therapy or intend to become pregnant they should communicate with their physician about the desirability of discontinuing the drug.

Meprobamate passes the placental barrier. It is present in umbilical cord blood at or near maternal plasma levels.

Meprobamate is present in breast milk of lactating mothers at concentrations two to four times that of maternal plasma. When use of meprobamate is contemplated in breastfeeding patients, the drug’s higher concentration in breast milk as compared to maternal plasma should be considered.

Patients should be warned that meprobamate may impair the mental and/or physical abilities required for performance of potentially hazardous tasks such as driving or operating machinery.

Central Nervous System

Drowsiness, ataxia, dizziness, slurred speech, headache, vertigo, weakness, paresthesias, impairment of visual accommodation, euphoria, overstimulation, paradoxical excitement, fast EEG activity.

Gastrointestinal

Nausea, vomiting, diarrhea.

Cardiovascular

Palpitation, tachycardia, various forms of arrhythmia, transient ECG changes, syncope; also hypotensive crisis (including one fatal case).

Allergic or Idiosyncratic

Allergic or idiosyncratic reactions are usually seen within the period of the first to fourth dose in patients having had no previous contact with the drug. Milder reactions are characterized by an itchy, urticarial, or erythematous maculopapular rash which may be generalized or confined to the groin. Other reactions have included leukopenia, acute nonthrombocytopenic purpura, petechiae, ecchymoses, eosinophilia, peripheral edema, adenopathy, fever, fixed drug eruption with cross reaction to carisoprodol, and cross sensitivity between meprobamate/mebutamate and meprobamate/carbromal.

More severe hypersensitivity reactions, rarely reported, include hyperpyrexia, chills, angioneurotic edema, bronchospasm, oliguria and anuria. Also, anaphylaxis, erythema multiforme, exfoliative dermatitis, stomatitis, proctitis, Stevens-Johnson syndrome and bullous dermatitis, including one fatal case of the latter following administration of meprobamate in combination with prednisolone.

In case of allergic or idiosyncratic reactions to meprobamate, discontinue the drug and initiate appropriate symptomatic therapy, which may include epinephrine, antihistamines, and in severe cases, corticosteroids. In evaluating possible allergic reactions, also consider allergy to excipients.

Hematologic (See also Allergic or Idiosyncratic.)

Agranulocytosis and aplastic anemia have been reported. These cases rarely were fatal. Rare cases of thrombocytopenic purpura have been reported.

Other

Exacerbation of porphyric symptoms.