Names and pronunciation
(kar-ba-maz′e-peen) Carbatrol, Carnexiv, Epitol, Equetro, Tegretol CR, TEGretol, TEGretol-XR
PDF page 232
Loading InternPractice…
Drug reference
(kar-ba-maz′e-peen) Carbatrol, Carnexiv, Epitol, Equetro, Tegretol CR, TEGretol, TEGretol-XR
PDF page 232
Func. class.: Anticonvulsant
PDF page 232
Chem. class.: Iminostilbene derivative
PDF page 232
Do not confuse: carBAMazepine/OXcarbazepine TEGretol/Tegrotol XR/Tequin/TRENtal
PDF page 232
ACTION: Exact mechanism unknown; appears to decrease polysynaptic responses and block posttetanic potentiation
PDF page 232
USES: Tonic-clonic, complex-partial, mixed seizures; trigeminal neuralgia; bipolar disorder
PDF page 232
Unlabeled uses: Neurogenic pain
PDF page 232
CONTRAINDICATIONS: Preg- nancy, hypersensitivity to carBAMazepine or tricyclics, MAOI therapy, bone marrow suppression Precautions: Breastfeeding, children <6 yr, glaucoma, AV or bundle branch block, cardiac/renal/hepatic disease, psychosis, alcoholism, hepatic porphyria
PDF page 232
Black Box Warning: Hematologic dis- ease, Asian patients or those with positive HLA-B 1502 or HLA-A 3101 alleles, agranulocytosis, leukopenia, neu- tropenia, thrombocytopenia DOSAGE AND ROUTES—NTI General tonic/clonic and complex partial seizures, mixed seizure patterns • Adult and child >12 yr: PO 200 mg bid, may be increased by 200 mg/day in weekly intervals, give in divided doses q6-8hr; maintenance 800-1200 mg/day, max 1600 mg/day (adult); max child 12-15 yr 1000 mg/day; max child >15 yr 1200 mg/day; EXTENDED RELEASE give bid; rectal administration of ORAL SUSPENSION 200 mg/10 mL or 6 mg/kg as a single dose • Child 6-12 yr: PO tablets 100 mg bid or extended release 50 mg qid; may increase by <100 mg weekly; max 1000 mg/day, usual dose 15-30 mg/kg/day • Child <6 yr: PO 10-20 mg/kg/day in 2-3 divided doses or 4 divided doses (suspen- sion), may increase every wk, do not use extended release, max 35 mg/kg/day Diabetic neuropathy (unlabeled) • Adult: PO 100 mg bid or 50 mg qid, titrate to 600-800 mg/day Acute mania and mixed episodes in bipolar I disorder • Adult: PO (Equetro only) 200 mg bid, increase by 200 mg/day until response, max 1600 mg/day Trigeminal neuralgia • Adult: PO 100 mg bid with meals; may increase 100 mg q12hr until pain subsides, max 1200 mg/day; maintenance 200-400 mg bid Black Box Warning: Asian patients for serious skin reaction; genetic test for HLA-B1502 allele prior to administra- tion; these patients may develop toxic epidermal necrolysis, Stevens-Johnson syndrome, DRESS; may be fatal • Seizures: character, location, duration, intensity, frequency, presence of aura, in mixed seizure disorder, worsening of symptoms may occur • Trigeminal neuralgia: facial pain, in- cluding location, duration, intensity, character, activity that stimulates pain • Renal studies: urinalysis, BUN, urine creatinine q3mo • Bipolar disorder: assess for symptoms at baseline and during treatment • DRESS: fever, lymphadenopathy with multiorgan involvement, including liver, kidney, cardiac; discontinue carBAMaze- pine Black Box Warning: Bone marrow de- pression: blood studies: CBC reticulocyte counts every week for 4 wk, then q3-6mo if on long-term therapy; if myelosuppres- sion occurs, product should be discontin- ued; blood dyscrasias: fever, sore throat, bruising, rash, jaundice, agranulocytosis, and aplastic anemia may occur • Blood studies: ALT, AST, bilirubin; se- rum calcium, may be decreased and lead to osteoporosis; cholesterol periodically • Drug levels during initial treatment or when changing dose; should remain at 4-12 mcg/mL; anorexia may indicate in- creased blood levels • Mental status: mood, sensorium, affect, behavioral changes, suicidal thoughts/behaviors; if mental status changes, notify prescriber • Eye problems: need for ophthalmic examinations prior to during, after treatment (slit lamp, funduscopy, to- nometry) • Allergic reaction: purpura, red, raised rash; if these occur, product should be discontinued; increased risk if past hy- persensitivity to hydantoins • Toxicity: bone marrow depression, nau- sea, vomiting, ataxia, diplopia, CV collapse • Hard candy, gum, frequent rinsing for dry mouth • Beers: avoid use in older adults unless safer alternative is unavailable; ataxia, impaired psychomotor function may occur
PDF pages 232, 233, 234
SIDE EFFECTS CNS: Drowsiness, dizziness, fatigue, headache, suicidal thoughts/behaviors CV: Hypertension, AV block, hypotension EENT: Dry mouth, blurred vision, diplo- pia, nystagmus ENDO: SIADH (geriatric patients) GI: Nausea, anorexia, increased hepatic enzymes, pancreatitis, hepatotoxicity GU: Retention, increased BUN, renal dysfunction HEMA: Thrombocytopenia, leukopenia, agranulocytosis, aplastic anemia, eosino- philia, lymphadenopathy INTEG: Rash, Stevens-Johnson syndrome, urticaria, photosensitivity, toxic epidermal necrolysis, DRESS, alopecia, pruritus RESP: Pulmonary hypersensitivity (fever, dyspnea, pneumonitis)
PDF page 233
INTERACTIONS • Increase: CNS toxicity—lithium; avoid concurrent use • Fatal reaction: MAOIs; do not use with- in 14 days of beginning carBAMazepine C • Do not use with nonnucleoside reverse transcriptase inhibitors (NNRTIs), nefazo- done Increase: carBAMazepine levels—CYP3A inhibitors (cimetidine, clarithromycin, dan- azol, dilTIAzem, erythromycin, FLUoxetine, fluvoxaMINE, isoniazid, valproic acid, verapamil, voriconazole), SSRIs, tricyclics; adjust dose if needed, or do not use together Increase: effects of desmopressin, lith- ium, lypressin, vasopressin Decrease: carBAMazepine effect— CYP1A2, CYP2C9 substrates Decrease: effect of CYP3A inducers Decrease: effects of benzodiazepines, doxycycline, felbamate, haloperidol, oral contraceptives, PHENobarbital, phenytoin, primidone, theophylline, thyroid hor- mones, warfarin; adjust dose as needed Decrease: carBAMazepine levels—CYP3A4 inducers (CISplatin, darunavir, delavirdine, DOXOrubicin, felbamate, nefazodone, OXcarbazepine, PHENobarbital, phenytoin, primidone, rifAMPin, theophylline); moni- tor carBAMazepine effectiveness Drug/Herb Decrease: carBAMazepine metabolism, increased levels—echinacea Decrease: anticonvulsant effect—St. John’s wort Drug/Food Increase: peak concentration of carBA Mazepine—grapefruit juice; avoid use Drug/Lab Test Decrease: serum calcium, sodium Increase: cholesterol
PDF page 233
TREATMENT OF OVERDOSE: Lavage, VS HIGH ALERT
PDF page 234
Available forms: Chewable tablets 100, 200 mg; tablets 100, 200, 300, 400 mg; extended-release tablets (XR) 100, 100, 200, 400 mg; oral suspension 100 mg/5 mL; extended-release capsules 100, 200, 300 mg
PDF page 233
Administer: PO route • When converting from tablets to oral suspension, give same amount/day, or regu- lar release to extended release same amount • Do not crush, chew extended-release tablet; extended-release capsule may be opened and beads sprinkled over food; patient should chew chewable tablet, not swallow it whole • With food, milk to decrease GI symptoms Suspension: Turn off NG/enteral feeding 15 min prior to and hold for 15 min after • Mix an equal amount of water, D5W, 0.9% NaCl when giving by NG tube; flush tube with 15-30 mL, do not give at same time as other liquid products or diluents • Shake oral suspension before use • Store at room temperature
PDF page 233
Assess:
PDF page 233
Evaluate: • Therapeutic response: decreased sei- zure activity; document on patient’s chart
PDF page 234
CLINICAL CONSIDERATIONS
PDF page 233
Patient and caregiver information: • To carry emergency ID stating pa- tient’s name, products taken, condition, prescriber’s name, and phone number • To avoid driving, other activities that re- quire alertness usually for the first 3 days of treatment; dizziness, drowsiness may occur • Not to discontinue medication quickly after long-term use; seizures may occur • To immediately report chills, rash, light-colored stools, dark urine, yellowing of skin and eyes, abdominal pain, sore throat, mouth ulcers, bruising, blurred vi- sion, dizziness, skin rash, fever • That urine may turn pink to brown • Not to use with grapefruit juice; to take on an empty stomach; that toxicity may occur • That ophthalmic examinations will be needed; to report changes in vision • Pregnancy/breastfeeding: to notify health care provider if pregnancy is planned or suspected; not to breastfeed; that if preg- nant, patient should register with American Antiepileptic Drug Pregnancy Registry (888- 233-2334), to use nonhormonal contraceptive
PDF page 234
PHARMACOKINETICS Onset slow; peak 4-5 hr (PO), 1.5 hr (sus- pension) metabolized by liver; excreted in urine, feces; crosses placenta, blood-brain barrier; excreted in breast milk; half-life 6-12 hr; protein binding 76%; metabolized by CYP3A4
PDF page 233