MEPROBAMATE

(me-proe-ba'mate)

Classifications: psychotherapeutic; carbamate; anxiolytic; sedative-hypnotic;
Therapeutic: antianxiety; sedative-hypnotic
Pregnancy Category: D
Controlled Substance: Schedule IV

Availability

200 mg, 400 mg tablets

Action

Carbamate derivative. CNS depressant actions similar to those of barbiturates. Acts on multiple sites in CNS and appears to block corticothalamic impulses.

Therapeutic Effect

Antianxiety agent. Hypnotic doses suppress REM sleep.

Uses

To relieve anxiety and tension of psychoneurotic states and as adjunct in disease states associated with anxiety and tension. Also used to promote sleep in anxious, tense patients.

Contraindications

History of hypersensitivity to meprobamate or related carbamates; ethanol intoxication; history of acute intermittent porphyria; pregnancy (category D), lactation, children <6 y.

Cautious Use

Impaired kidney or liver function; convulsive disorders; history of alcoholism or drug abuse; patients with suicidal tendencies.

Route & Dosage

Sedative
Adult: PO 1.2–1.6 g/d in 3–4 divided doses (max: 2.4 g/d)
Child: PO 100–200 mg b.i.d. or t.i.d.

Hypnotic
Adult: PO 400–800 mg
Geriatric: PO 200 mg 2–3 times/d
Child: PO 200 mg

Administration

Oral

Give with food to minimize gastric distress.
Treatment physical dependence by gradual drug withdrawal over 1–2 wk to prevent onset of withdrawal symptoms.
Store at 15°–30° C (59°–86° F) unless otherwise specified by manufacturer.

Adverse Effects (≥1%)

Body as a Whole: Allergy or idiosyncratic reactions (itchy, urticarial, or erythematous maculopapular rash; exfoliative dermatitis, petechiae, purpura, ecchymoses, eosinophilia, peripheral edema, angioneurotic edema, adenopathy, fever, chills, proctitis, bronchospasm, oliguria, anuria, Stevens-Johnson syndrome); anaphylaxis. CNS: Drowsiness and ataxia, dizziness, vertigo, slurred speech, headache, weakness, paresthesias, impaired visual accommodation, paradoxic euphoria and rage reactions, seizures in epileptics, panic reaction, rapid EEG activity. CV: Hypotensive crisis, syncope, palpitation, tachycardia, arrhythmias, transient ECG changes, circulatory collapse (toxic doses). GI: Anorexia, nausea, vomiting, diarrhea. Hematologic: Aplastic anemia (rare): leukopenia, agranulocytosis, thrombocytopenia, exacerbation of acute intermittent porphyria. Respiratory: Respiratory depression.

Diagnostic Test Interference

Meprobamate may cause falsely high urinary steroid determinations. Phentolamine tests may be falsely positive; meprobamate should be withdrawn at least 24 h and preferably 48–72 h before the test.

Interactions

Drug: Alcohol entacapone, tricyclic antidepressants, antipsychotics, opiates, sedating antihistamines, pentazocine, tramadol, maois, sedative-hypnotics, anxiolytics may potentiate CNS depression. Herbal: Kava, valerian may potentiate sedation.

Pharmacokinetics

Absorption: Well absorbed from GI tract. Peak: 1–3 h. Onset: 1 h. Distribution: Uniformly throughout body; crosses placenta. Metabolism: Rapidly in liver. Elimination: Renally excreted; excreted in breast milk. Half-Life: 10–11 h.

Nursing Implications

Assessment & Drug Effects

Supervise ambulation, if necessary. Older adults and debilitated patients are prone to oversedation and to the hypotensive effects, especially during early therapy.
Utilize safety precautions for hospitalized patients. Hypnotic doses may cause increased motor activity during sleep.
Consult physician if daytime psychomotor function is impaired. A change in regimen or drug may be indicated.
Withdraw gradually in physically dependent patients to prevent preexisting symptoms or withdrawal reactions within 12–48 h: Vomiting, ataxia, muscle twitching, mental confusion, hallucinations, convulsions, trembling, sleep disturbances, increased dreaming, nightmares, insomnia. Symptoms usually subside within 12–48 h.

Patient & Family Education

Take drug as prescribed. Psychic or physical dependence may occur with long-term use of high doses.
Be aware that tolerance to alcohol will be lowered.
Make position changes slowly, especially from lying down to upright; dangle legs for a few minutes before standing.
Avoid driving or engaging in hazardous activities until response to drug is known.
Report immediately onset of skin rash, sore throat, fever, bruising, unexplained bleeding.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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