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Carbamazepine (Tegretol, Carbatrol, Atretol)

Category:

  • Miscellaneous

Description:

  • Anticonvulsant; antineuralgic; antimanic; antipsychotic

Indications:

  • Tonic-clonic, complex-partial, mixed seizures

  • Trigeminal neuralgia

Contraindications:

  • Hypersensitivity to tricyclic antidepressants, bone marrow depression, concomitant use of MAO inhibitor

Precautions:

  • Pregnancy category C

  • Glaucoma, hepatic disease, renal disease, cardiac disease, psychosis

  • Child < age 6

Adverse Reactions (Side Effects):

  • CNS: ataxia, confusion, dizziness, drowsiness, hallucinations, headache, parlaysis

  • CV: CHF, hypertension, hypotension, aggravation of coronary artery disease

  • EENT: bBlurred vision, conjunctivitis, diplopia, dry mouth, nystagmus, tinnitis

  • GI: abdominal pain, anorexia, constipation, diarrhea, glossitis, hepatitis, nausea

  • HEME: agranulocytosis, aplastic anemia, eosinophilia, leukocytosis, neutropenia, thrombocytopenia

  • RESP: fever, dyspnea, pneumonitis

  • SKIN: rash, Stevens-Johnson syndrome, urticaria  

 

 

 

Dosage:

Administered orally (tablet, chewable tablet, suspension)

  • Adult Dose:

    • Seizures: 

      • PO 200mg twice daily

      • may increase by 200mg daily in divided doses every 6-8 hours

      • maintenance 800-1200mg daily

      • maximum dose 1200mg per day

    • Trigeminal neuralgia: 

      • PO 100mg twice daily

      • may increase 100mg every 12 hours until pain subsides

      • not to exceed 1.2 grams daily

      • maintenance 200-400mg twice daily

    • Antidiuretic: 

      • PO 300-600mg daily as sole therapy

      • 200-400mg daily if concurrent with other antidiuretic agents

    • Antipsychotic: 

      • PO 200-400 mg/day divided 3-4 times per day

      • max 1600mg daily

  • Child < age 12:  

    • Seizures: 

      • PO 10-20 mg/kg/day in 2-3 divided doses

Drug Interactions:  

  • Calcium channel blockers (CCB): Verapamil and diltiazem reduce the metabolism of carbamazepine leading to increased carbamazepine toxicity when these CCB’s are added to chronic carbamazepine therapy; enzyme induction by carbamazepine can reduce the bioavailability of CCB’s that undergo extensive 1st-pass hepatic clearance, like felodipine (94% reduction)

  • Propoxyphene: reduces carbamazepine levels

  • Valproic acid: can increase, decrease, or have no effect on carbamazepine; carbamazepine decreases valproic acid levels

  • Theophylline: carbamazepine reduces levels and therapeutic effect

  • Omeprazole: may increase carbamazepine concentrations

  • Oral anticoagulants: decreased prothrombin time

  • Phenytoin: concurrent use reduces serum concentrations of both

  • Metronidazole and isoniazid: increases carbamazepine concentrations with toxicity

  • Ethinyl estradiol, oral contraceptives: carbamazepine-induced metabolic induction may lead to menstrual irregularities and unplanned pregnancies

  • Doxycycline: carbamazepine reduces doxycycline levels and antibiotic effects

  • Erythromycin and clarithromycin: increased carbamazepine levels

  • Corticosteroids: carbamazepine reduces levels and therapeutic effects

  • Cimetadine: Transient (1 week) increases in carbamazepine levels

 

The information contained here is an abbreviated summary. For more detailed and complete information, consult the manufacturer's product information sheets or standard textbooks. Source: Operational Medicine 2001,  Health Care in Military Settings, NAVMED P-5139, May 1, 2001, Bureau of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington, D.C., 20372-5300

OB-GYN 101: Introductory Obstetrics & Gynecology
© 2003, 2004, 2005, 2008 Medical Education Division, Brookside Associates, Ltd.
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