Apo-Carbamazepine, Carbatrol, Epitol, Equetro, Novo-Carbamaz, Tegretol, Tegretol CR, Tegretol-XR, Teril
Therapeutic: anticonvulsants, mood stabilizers
Treatment of tonic-clonic, mixed, and complex-partial seizures. Management of pain in trigeminal neuralgia or diabetic neuropathy. Equetro only: Acute mania and mixed mania. Unlabeled Use: Other forms of neurogenic pain.
Decreases synaptic transmission in the CNS by affecting sodium channels in neurons. Therapeutic Effects: Prevention of seizures. Relief of pain in trigeminal neuralgia. Decreased mania.
Adverse Reactions/Side Effects
CNS: ataxia, drowsiness, fatigue, psychosis, sedation, suicidal behavior or ideation, vertigo. EENT: blurred vision, nystagmus, corneal opacities. Resp: pneumonitis. CV: CHF, edema, hypertension, hypotension, syncope. GI: hepatitis, pancreatitis, weight gain. GU: hesitancy, urinary retention. Derm: photosensitivity, RASHES, STEVENS-JOHNSON SYNDROME, TOXIC EPIDERMAL NECROLYSIS, urticaria. Endo: syndrome of inappropriate antidiuretic hormone (SIADH), hyponatremia. Hemat: AGRANULOCYTOSIS, APLASTIC ANEMIA, THROMBOCYTOPENIA, eosinophilia, leukopenia. Misc: chills, fever, lymphadenopathy, elevated liver enzymes, multiorgan hypersensitivity reactions, hepatic failure (rare).
PHYSICAL THERAPY IMPLICATIONS
Examination and Evaluation
Monitor skin reactions such as rash, itching/burning skin, hives, exfoliation, and dermatitis. Notify physician immediately because certain skin reactions may indicate serious hypersensitivity reactions (Stevens-Johnson syndrome, toxic epidermal necrosis).
Be alert for signs of agranulocytosis (fever, sore throat, mucosal lesions, signs of infection), aplastic anemia (unusual fatigue, weakness, dizziness, pallor), thrombocytopenia (bruising, nose bleeds, bleeding gums), or fatigue and poor health that might be due to other anemias and blood dyscrasias. Report these signs to the physician immediately. Periodic blood tests may be needed to monitor WBC and RBC counts.
Document the number, duration, and severity of seizures to help determine if this drug is effective in reducing seizure activity.
If used to treat trigeminal neuralgia or other types of neurogenic pain, assess pain using visual analogue scales or other appropriate pain scales to document whether this drug is successful in helping manage the patient's pain.
If treating acute or mixed mania, monitor the patient's mood and behavior and report changes in manic symptoms (excitement, agitation) to help determine drug effectiveness.
Assess vertigo, ataxia, or syncope that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.
Be alert for suicidal thoughts and ideology; notify physician immediately if patient exhibits signs of depression or other changes in mood and behavior.
Monitor daytime drowsiness, confusion, agitation, or psychosis-like reactions. Repeated or excessive symptoms may require change in dose or medication.
Assess blood pressure (BP) and compare to normal values (See Appendix F). Report changes in BP, either a problematic decrease in BP (hypotension) or a sustained increase in BP (hypertension).
Assess signs of congestive heart failure such as dyspnea, rales/crackles, peripheral edema, jugular venous distention, and exercise intolerance. Report these signs to the physician.
Assess peripheral edema using girth measurements, volume displacement, and measurement of pitting edema (See Appendix N). Report increased swelling in feet and ankles or a sudden increase in body weight due to fluid retention.
Be alert for signs of pneumonitis, including dyspnea, cough, shortness of breath, fever, and rales. Report these signs to the physician.
Monitor signs of fluid-electrolyte imbalance due to SIADH. SIADH causes increased water retention that leads to relatively low sodium concentration (hyponatremia). Symptoms include confusion, lethargy, weakness, myoclonus, and depressed reflexes. Severe or sudden onset may also cause seizures, ataxia, nystagmus, tremor, dysarthria, dysphagia, and coma. Notify physician if these signs occur.
Periodically assess body weight and other anthropometric measures (body mass index, body composition). Report a rapid or unexplained weight gain or increased body fat.
Guard against falls and trauma (hip fractures, head injury, and so forth), especially if vertigo, syncope, or ataxia affects gait and balance. Implement fall-prevention strategies, especially if balance is impaired (See Appendix E).
To minimize orthostatic hypotension, patient should move slowly when assuming a more upright position.
Because of the risk of CHF and abnormal BP responses, use caution during aerobic exercise and other forms of therapeutic exercise. Assess exercise tolerance frequently (BP, heart rate, fatigue levels), and terminate exercise immediately if any untoward responses occur (See Appendix L).
Causes photosensitivity; use care if administering UV treatments. Advise patient to avoid direct sunlight and use sunscreens and protective clothing.
Advise patient to avoid alcohol and other CNS depressants because of the increased risk of sedation and adverse effects.
Advise patients on prolonged antiseizure therapy not to discontinue medication without consulting their physician. Abrupt withdrawal may cause increased seizures.
Advise patient about the risk of daytime drowsiness and decreased attention and mental focus. Use care if driving or in other activities that require strong concentration and fast responses.
Advise patient about the likelihood of GI reactions, and to report signs of hepatotoxicity (anorexia, abdominal pain, severe nausea and vomiting, yellow skin or eyes, fever, sore throat, malaise, weakness, facial edema, lethargy, unusual bleeding or bruising) or pancreatitis (upper abdominal pain after eating, indigestion, weight loss, oily stools).
Instruct patient and family/caregivers to report other troublesome side effects such as severe or prolonged chills, fever, swollen/tender lymph nodes, visual problems (double vision, nystagmus), or urinary problems (hesitancy, retention).
Absorption: Absorption is slow but complete. Suspension produces earlier, higher peak and lower trough levels.
Distribution: Widely distributed. Crosses the blood-brain barrier. Crosses the placenta rapidly and enters breast milk in high concentrations.
Protein Binding: Carbamazepine—75–90%; epoxide—50%.
Metabolism and Excretion: Extensively metabolized in the liver by cytochrome P450 3A4 to active epoxide metabolite; epoxide metabolite has anticonvulsant and antineuralgic activity.
Half-life: Carbamazepine: single dose—25–65 hr; chronic dosing—Children—8–14 hr; Adults—12–17 hr; epoxide: 34 ± 9 hr.
TIME/ACTION PROFILE (anticonvulsant activity)
|ROUTE ||ONSET ||PEAK ||DURATION |
|PO ||up to one month* ||4–5 hr† ||6–12 hr |
|PO-ER ||up to one month* ||2–3–12 hr† ||12 hr |
Contraindicated in: Hypersensitivity; Bone marrow suppression; Concomitant use or use within 14 days of MAO inhibitors; OB: Use only during pregnancy if potential benefits outweigh risks to the fetus; additional vitamin K during last weeks of pregnancy has been recommended; Lactation: Discontinue drug or bottle feed.
Use Cautiously in: All patients (may ↑ risk of suicidal thoughts/behaviors); Cardiac or hepatic disease; Renal failure (dosing adjustment required for ClCr <10 mL/min; Increased intraocular pressure; Geri: Older men with prostatic hyperplasia may be at increased risk for acute urinary retention or difficulty initiating stream.
Exercise Extreme Caution in: Patients positive for HLA-B*1502 allele (unless benefits clearly outweigh the risks).
Drug-Drug: May ↑ metabolism of and therefore ↓ levels/effectiveness of corticosteroids, doxycycline, felbamate, quinidine, warfarin, estrogen-containing contraceptives, barbiturates, cyclosporine, benzodiazepines, theophylline, lamotrigine, phenytoin, topiramate, valproic acid, bupropion, and haloperidol. Danazol ↑ blood levels (avoid concurrent use if possible). Concurrent use (within 2 wk) of MAO inhibitors may result in hyperpyrexia, hypertension, seizures, and death. Verapamil, diltiazem, propoxyphene, itraconazole, ketoconazole, erythromycin, clarithromycin, SSRIs, antidepressants, or cimetidine may inhibit the hepatic metabolism or carbamazepine and ↑ levels; may cause toxicity. Enzyme inducers such as rifampin, phenobarbital, phenytoin, primidone, and methsuximide may ↓ serum concentration of carbamazepine. May ↑ risk of hepatotoxicity from isoniazid. Felbamate ↓ carbamazepine levels but ↑ levels of active metabolite. May ↓ effectiveness and ↑ risk of toxicity from acetaminophen. May ↑ risk of CNS toxicity from lithium. May ↓ duration of action of nondepolarizing neuromuscular blocking agents.
Drug-Food: Grapefruit juice ↑ serum levels and oral bioavailability by 40% and therefore may ↑ effects.
PO (Adults): Anticonvulsant—200 mg twice daily (tablets) or 100 mg 4 times daily (suspension); ↑ by 200 mg/day q 7 days until therapeutic levels are achieved (range is 600–1200 mg/day in divided doses q 6–8 hr; not to exceed 1 g/day in 12–15 yr olds. Extended-release products are given twice daily (XR, CR). Antineuralgic—100 mg twice daily or 50 mg 4 times daily (suspension); ↑ by up to 200 mg/day until pain is relieved, then maintenance dose of 200–1200 mg/day in divided doses (usual range, 400–800 mg/day).
PO (Children 6–12 yr): 100 mg twice daily (tablets) or 50 mg 4 times daily (suspension) ↑ by 100 mg weekly until therapeutic levels are obtained (usual range 400–800 mg/day; not to exceed 1 g/day). Extended-release products (XR, CR) are given twice daily.
PO (Children <6 yr): 10–20 mg/kg/day in 2–3 divided doses; may be ↑ at weekly intervals until optimal response and therapeutic levels are achieved. Usual maintenance dose is 250–350 mg/day (not to exceed 35 mg/kg/day).
Availability (generic available)
Tablets: 200 mg. Chewable tablets: 100 mg, 200 mg. Extended-release capsules: 100 mg, 200 mg, 300 mg. Extended-release tablets: 100 mg, 200 mg, 400 mg. Oral suspension (citrus/vanilla flavor): 100 mg/5 mL.