CARBAMAZEPINE 
(kar-ba-maz'e-peen)
Apo-Carbamazepine  , Carbatrol, Epitol, Equetro, Mazepine , PMS-Carbamazepine , Tegretol, Tegretol XR, Teril
Classifications: central nervous system agent; anticonvulsant; tricyclic
Pregnancy Category: D
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100 mg chewable tablets; 200 mg tablets; 100 mg, 200 mg, 400 mg sustained-release tablets; 100 mg, 200 mg, 300 mg sustained-release capsules; 100 mg/5 mL suspension
Structurally related to tricyclic antidepressants (TCAs) but lacks antidepressant properties. Anticonvulsant actions appear
qualitatively similar to those of phenytoin. Like phenytoin, provides relief in trigeminal neuralgia by reducing synaptic
transmission within trigeminal nucleus. Also has sedative, anticholinergic, antidepressant, and muscle relaxant (by inhibition
of neuromuscular transmission) effects and slight analgesic actions.
Effective anticonvulsant for a range of seizure disorders and as an adjuvant reduces depressive signs and symptoms and stabilizes
mood. It is effective for pain and other symptoms associated with neurologic disorders.
Alone or concomitantly with other anticonvulsants in treatment of grand mal and psychomotor or temporal lobe epilepsy and
mixed seizures in patients who have not responded satisfactorily to other agents. Also used for symptomatic treatment of trigeminal
(tic douloureux) and glossopharyngeal neuralgias and for pain and paroxysmal symptoms associated with multiple sclerosis and
other neurologic disorders.
Certain psychiatric disorders including prophylaxis and treatment of manic-depressive illness, treatment of schizoaffective
illness, resistant schizophrenia, dyscontrol syndrome; for management of alcohol withdrawal, rage outbursts, and for antidiuretic
effect in diabetes insipidus.
Hypersensitivity to carbamazepine and to TCAs; history of myelosuppression or hematologic reaction to other drugs; increased
IOP; SLE; cardiac, hepatic, or renal disease; coronary artery disease; hypertension; pregnancy (category D), lactation. Safe
use in children <6 mo not established.
The older adult; history of cardiac disease.
Epilepsy
Adult: PO 200 mg b.i.d., gradually increased to 800–1200 mg/d in 3–4 divided doses. Tegretol XR dosed b.i.d.
Child: PO
<6 y: 10–20 mg/kg/d, may gradually increase weekly, recommended max 35 mg/kg/d in 3–4 divided doses; 6–12 y: 100 mg b.i.d., gradually increased to 400–800 mg/d in 3–4 divided doses (max: 1 g/d); <6 y: 20–30 mg/kg/d in 3–4 divided doses
Trigeminal Neuralgia
Adult: PO 100 mg b.i.d., gradually increased by 100 mg increments q12h until relief; usual dose 200–800 mg/d in 3–4 divided
doses (max: 1.2 g/d). Tegretol XR dosed b.i.d.
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Oral
- Do not administer within 14 d of patient receiving a MAO inhibitor.
- Give with a meal to increase absorption.
- Ensure that chewable tablets are chewed or crushed before being swallowed with a liquid.
- Ensure that sustained-release form of drug is not chewed or crushed. It must be swallowed whole.
- Do not administer carbamazepine suspension simultaneously with other liquid medications: a precipitate may form in the stomach.
Body as a Whole: Myalgia, arthralgia, leg cramps, carbamazepine-induced SLE. CV: Edema, syncope, arrhythmias, heart block. GI: Nausea, vomiting, anorexia, abdominal pain, diarrhea, constipation, dry mouth and pharynx, abnormal liver function tests,
hepatitis, cholestatic and hepatocellular jaundice, pancreatitis. Endocrine: Hypothyroidism, SIADH. Hematologic:
Aplastic anemia, leukopenia (transient), leukocytosis, agranulocytosis, eosinophilia, thrombocytopenia. CNS: Dizziness, vertigo, drowsiness, disturbances of coordination, ataxia, confusion, headache, fatigue, listlessness, speech difficulty,
development of minor motor seizures, hyperreflexia, akathisia, involuntary movements, tremors, visual hallucinations, activation
of latent psychosis, aggression; agitation, respiratory depression. Skin: Skin rashes, urticaria, petechiae, erythema multiforme, Stevens-Johnson syndrome, photosensitivity reactions, altered skin
pigmentation, exfoliative dermatitis, alopecia. Special Senses: Abnormal hearing acuity, scotomas, conjunctivitis, blurred vision, transient diplopia, oculomotor disturbances, oscillopsia,
nystagmus. Urogenital: Urinary frequency or retention, oliguria, impotence.
False-negative pregnancy test results with tests involving human chorionic gonadotropin.
Drug: Serum concentrations of other anticonvulsants may decrease because of increased metabolism; verapamil,
erythromycin,
ketoconazole,
nefazadone may increase carbamazepine levels; decreases hypoprothrombinemic effects of oral anticoagulants; increases metabolism of estrogens, thus decreasing effectiveness of oral contraceptives. Herbal:
Ginkgo may decrease anticonvulsant effectiveness.
Absorption: Slowly absorbed from GI tract. Peak: 2–8 h. Distribution: Widely distributed; high concentrations in CSF; crosses placenta; distributed into breast milk. Metabolism: Metabolized in liver; can induce liver microsomal enzymes. Elimination: Excreted in urine and feces. Half-Life: 14–16 h (decreases with long-term use).
Assessment & Drug Effects
- Lab tests: Baseline and periodic CBCs including platelets, reticulocytes, serum electrolytes and serum iron, liver function
tests, BUN, and complete urinalysis.
- At least 3 mo into therapy, it is recommended that physician attempt dosage reduction or termination of drug therapy, if possible,
in patients with trigeminal neuralgia. Some patients develop tolerance to the effects of carbamazepine.
- Monitor for the following reactions, which commonly occur during early therapy: drowsiness, dizziness, light-headedness, ataxia,
gastric upset. If these symptoms do not subside within a few days, dosage adjustments may be indicated.
- Withhold drug and notify physician if any of the following signs of myelosuppression occur: RBC <4 million/mm3, Hct <32%, Hgb <11 g/dL, WBC <4000/mm3, platelet count <100,000/mm3, reticulocyte count <20,000/mm3, serum iron >150 mg/dL.
- Monitor for toxicity, which can develop when serum concentrations are even slightly above the therapeutic range.
- Monitor I&O ratio and vital signs during period of dosage adjustment. Report oliguria, signs of fluid retention, changes in
I&O ratio, and changes in BP or pulse patterns.
- Cardiac syncope may resemble epileptic seizures. Therefore, it is recommended that patients who experience an apparent increase
in frequency of seizures or a change in their character should be checked by continuous ECG monitoring for 24 h.
- Doses higher than 600 mg/d may precipitate arrhythmias in patients with heart disease.
- Confusion and agitation may be aggravated in the older adult; therefore, side rails and supervision of ambulation may be indicated.
Patient & Family Education
- Discontinue drug and notify physician immediately if early signs of toxicity or a possible hematologic problem appear, (e.g.,
anorexia, fever, sore throat or mouth, malaise, unusual fatigue, tendency to bruise or bleed, petechiae, ecchymoses, bleeding
gums, nose bleeds).
- Avoid hazardous tasks requiring mental alertness and physical coordination until reaction to drug is known, since dizziness,
drowsiness, and ataxia are common adverse effects.
- Remain under close medical supervision throughout therapy.
- Avoid excessive sunlight, as photosensitivity reactions have been reported. Apply a sunscreen (if allowed) with SPF of 12
or above.
- Carbamazepine may cause breakthrough bleeding and may also affect the reliability of oral contraceptives.
- Be aware that abrupt withdrawal of any anticonvulsant drug may precipitate seizures or even status epilepticus.
- Do not breast feed while taking this drug.
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