Generic Name

Carbamazepine

Precaution

Lactation; CV disease, hepatic or renal disorders, history of blood disorders or haematological reactions to other drugs; glaucoma; skin disorders; elderly, patients on MAO inhibitors; abrupt withdrawal of treatment. Lactation: Enters breast milk; not recommended (AAP states compatible with nursing; however, adverse reactions in breastfeeding infant are possible; take into account the importance of the drug to the mother before deciding to discontinue breastfeeding or the drug)

Indication

Epilepsy, Schizophrenia, Bipolar disorder, Trigeminal neuralgia

Contra Indication

Hypersensitivity; bone marrow depression; porphyria, pregnancy.

Dose

N/A

Side Effect

>10% Ataxia (15%),Dizziness (44%),Drowsiness (32%),Nausea (29%),Vomiting (18%) 1-10% Dry mouth (8%) Rare MI,Stevens-Johnson syndrome Hepatic failure,Punctate cortical lens opacities,Syndrome of inappropriate antidiuretic hormone secretion (SIADH) Frequency Not Defined Hemopoietic system: Aplastic anemia, agranulocytosis, pancytopenia, bone marrow depression, thrombocytopenia, leukopenia, leukocytosis, eosinophilia, anemia, acute intermittent porphyria, variegate porphyria, porphyria cutanea tarda Skin: Toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS) (see Black Box Warnings), pruritic and erythematous rashes, urticaria, photosensitivity reactions, alterations in skin pigmentation, exfoliative dermatitis, erythema multiforme and nodosum, purpura, aggravation of disseminated lupus erythematosus, alopecia, diaphoresis, and onychomadesis Cardiovascular system: Congestive heart failure, edema, aggravation of hypertension, hypotension, syncope and collapse, aggravation of coronary artery disease, arrhythmias and AV block, thrombophlebitis, thromboembolism, and adenopathy or lymphadenopathy Liver: Abnormalities in liver function tests, cholestatic and hepatocellular jaundice, hepatitis; very rare cases of hepatic failure Pancreatic: Pancreatitis Respiratory System: Pulmonary hypersensitivity characterized by fever, dyspnea, pneumonitis, or pneumonia Genitourinary System: Urinary frequency, acute urinary retention, oliguria with elevated blood pressure, azotemia, renal failure, and impotence (rare reports of impaired male fertility and/or abnormal spermatogenesis) Laboratory: Albuminuria, glycosuria, elevated BUN, decreased plasma calcium, and microscopic deposits in the urine Nervous system: Dizziness, drowsiness, disturbances of coordination, confusion, headache, fatigue, blurred vision, visual hallucinations, transient diplopia, oculomotor disturbances, nystagmus, speech disturbances, abnormal involuntary movements, peripheral neuritis and paresthesias, depression with agitation, talkativeness, tinnitus, hyperacusis, neuroleptic malignant syndrome; isolated cases of neuroleptic malignant syndrome Digestive system: Nausea, vomiting, gastric distress and abdominal pain, diarrhea, constipation, anorexia, and dryness of the mouth and pharynx, including glossitis, and stomatitis Eyes: Scattered punctate cortical lens opacities, increased intraocular pressure as well as conjunctivitis Musculoskeletal system: Aching joints and muscles, and leg cramps Metabolism: Fever and chills; SIADH; cases of frank water intoxication, with decreased serum sodium (hyponatremia) and confusion; decreased levels of plasma calcium leading to osteoporosis Potentially Fatal: Agranulocytosis, aplastic anaemia, hepatic failure, severe exfoliative dermatitis and Stevens-Johnson syndrome.

Pregnancy Category

Mode of Action

Carbamazepine reduces polysynaptic responses and blocks post-tetanic potentiation. It is effective in partial and generalised convulsions as well as in mixed types but not in petit mal seizures. It reduces or abolishes pain in trigeminal and glossopharyngeal neuralgia.

Interaction

Increased plasma levels w/ CYP3A4 inhibitors (e.g. cimetidine). Decreased plasma levels w/ CYP3A4 inducers (e.g. cisplatin). Increased risk of neurotoxic side effects w/ lithium. May decrease the effect of hormonal contraceptives. Increased plasma levels of active metabolite carbamazepine-10, 11-epoxide w/ loxapine, quetiapine, primidone, progabide, valproic acid and valpromide. May increase cyclophosphamide levels. May reduce exposure of aripiprazole. May reduce plasma levels of tacrolimus, temsirolimus and lapatinib. May increase risk of isoniazid-induced hepatotoxicity. Risk of symptomatic hyponatraemia w/ diuretics (e.g. hydrochlorothiazide, furosemide). Potentially Fatal: May decrease serum concentrations of nefazodone and its active metabolites. Toxic reactions may develop when taken concurrently w/ MAOIs.

Pregnancy Category Note

Pregnancy category: D Lactation: Enters breast milk; not recommended (AAP states compatible with nursing; however, adverse reactions in breastfeeding infant are possible; take into account the importance of the drug to the mother before deciding to discontinue breastfeeding or the drug)

Adult Dose

Oral Epilepsy Adults - Initial: Either 200 mg b.i.d. for tablets and XR tablets, or 1 teaspoon q.i.d. for suspension (400 mg/day). Increase at weekly intervals by adding up to 200 mg/day using a b.i.d or a t.i.d. or q.i.d. regimen of the either formulations until the optimal response is obtained. Doses up to 1600 mg daily have been used in adults in rare instances. Maintenance: usually 800-1200 mg daily. Trigeminal neuralgia Adult: Initially, 100-200 mg bid, increased gradually as needed. Maintenance: 400-800 mg daily in divided doses. Max: 1.2 g daily. Prophylaxis of bipolar disorder Adult: Initially, 400 mg daily in divided doses, increased gradually as necessary. Maintenance: 400-600 mg daily in divided doses. Max: 1.6 g daily.

Child Dose

Epilepsy <6 Years Initial (oral suspension): 10-20 mg/kg/day PO q6hr Initial (tablet): 10-20 mg/kg/day PO q8-12hr Maintenance: For tablets or suspension may divide frequency into 3-4 times daily not to exceed 35 mg/kg/day 6-12 Years Initial (oral suspension): 50 mg PO q6hr Initial (tablet, immediate- or extended-release): 100 mg PO q12hr; may increase qWeek by 100 mg/day Maintenance: 400-800 mg/day PO q6-8hr (immediate-release); q12hr (extended-release) Not to exceed 1000 mg/day >12 Years Initial (oral suspension): 10 mL (200 mg) PO q6hr Initial (tablet, immediate- or extended-release): 200 mg PO q12hr May increase by up to 200 mg/day qWeek; q12hr (extended-release tablet); q6-8hr (other formulations) 12-15 years: Dose not to exceed 1000 mg/day >15 years: Dose not to exceed 1200 mg/day

Renal Dose

N/A

Administration

Should be taken with food. Avoid grapefruit juice.