Carbamazepine

Anti-epileptic · Iminostilbene

Indications

Prophylaxis of manic depressive psychosis unresponsive to lithium. Epilepsy: Generalized tonic clonic and partial seizures. Trigeminal neuralgia. Diabetic neuropathy.

Dosage

Adults: Manic depressive psychosis: Initially 400 mg daily in divided doses increasing gradually until symptoms controlled; max 1.6 gm daily in divided doses. Usual range, 400- 600 mg daily. Epilepsy: Initially 100-200 mg once or twice daily increasing slowly to optimum dosage, usually 800 mg-1.2 gm daily in divided doses. Max 1.6 gm daily. Trigeminal neuralgia: Initially 100 mg once or twice daily increasing gradually to control, usually 600-800 mg daily in divided doses; max 1.6 gm daily. Diabetic neuropathy: Initially 100 mg once or twice daily, increased gradually according to response, usual dose 200 mg three to four times daily. Max 1.6 gm daily. Children: Focal and generalised tonic-clonic seizures, trigeminal neuralgia, prophylaxis of bipolar disorder: 1 mth-12 yr, initially 5 mg/kg at night or 2.5 mg/kg twice daily, increased as necessary by 2.5-5 mg/kg every 3-7 days; usual…

Adverse Effects

Gastric upset, ataxia, fatigue, headache, visual disturbances, wt gain, raised LFTs, diplopia, dry mouth, drowsiness and dizziness. Oedema and rarely hyponatraemia. Blood dyscrasias, rashes, toxic epidermal necrolysis, hair loss. Acute renal failure, lymph-node enlargement, cardiac conduction disturbances, angioedema, pancreatitis, hepatitis and cholestatic jaundice.

Risk Factor (Pregnancy/Lactation)

Pregnancy: Positive evidence of risk: Use only when no safer alternative exists for a serious problem. Lactation: Contraindicated or not recommended. Contraindications: A-V conduction abnormalities unless paced. History of myelosuppression or hepatic porphyria. Hypersensitivity to oxcarbazepine, TCADs, phenytoin. Precautions: Severe CVS disease. Hepatic or renal disorders. Elderly. Perform liver function tests and check blood count regularly. Glaucoma, previous psychosis, mixed seizures. Maintain adequate intake of vit D. Risk of serious skin reactions.

Interactions

Oral anticoagulants, MAOIs, combined oral contraceptives. Erythromycin, isoniazid, cimetidine, dextropropoxyphene, diltiazem, verapamil, viloxazine. phenytoin, lithium, paracetamol. Inhibitors, inducers or substrates of CYP3A4, macrolides, rifampicin, azole antifungals, loratadine, grapefruit juice, protease inhibitors, antipsychotics, isotretinoin, St John's wort, nicotinamide, digoxin, doxycycline, calcium channel blockers, levothyroxine, steroids, immunosuppressants, trazodone, mianserin, TCADs, SSRIs, diuretics, non-depolarising muscle relaxants, other anticonvulsants, benzodiazepines, methadone, theophylline, omeprazole, acetazolamide, danazol, alcohol, mefloquine, cytotoxics, tramadol, tibolone, toremifene, metoclopramide, paracetamol, buprenorphine, bupropion, aprepitant, tadalafil, imatinib, lapatinib.

Advice to Patient

Take with meals. Do not chew or crush extended release tablets. Do not take oral suspension with other liquid drugs or diluents. If you cannot swallow capsule, open it and sprinkle contents on food. Contact prescriber if there is change in mental status, change in memory, muscle cramps, tremors, weakness, sore throat, abdominal cramps, loss of appetite, vomiting, constipation, mouth ulcers, change in gait, swelling in glands, jaundice, skin rash, irritation, worsening of seizure, loss of seizure control, unusual bruising or bleeding, blood in mouth/urine/stool. Avoid grapefruit juice during therapy. Avoid alcohol during therapy. Take sufficient amount of fluids (2-3 litres per day) to maintain hydration, unless restricted by the prescriber. Use sunscreen, wear protective clothing and eyewear, avoid direct sunlight to prevent photosensitivity. Carry identification card that you have…

Pharmacokinetics

Absorption: Slowly from the GI tract. Metabolism: Hepatic. Bioavailability: Oral: 75%-85%; relative bioavailability of extended release tab to susp: 89%; relative bioavailability of IV to oral formulation: 70%. Half-life elimination: Note: Half-life is variable because of autoinduction which is usually complete 3-5 wks after initiation of a fixed carbamazepine regimen. Carbamazepine: Initial: 25-65 hrs; Extended release: 35-40 hrs; Multiple doses: Children: 8-14 hrs; Adults: 12-17 hrs. Epoxide metabolite: Initial: 34 ± 9 hrs. Time to peak, serum: Unpredictable: Immediate release: Multiple doses: Susp: 1.5 hr; tab: 4-5 hrs. Extended release: 12-26 hrs (single dose), 4-8 hrs (multiple doses). Excretion: Urine (72%). Faeces (28%).

Brands with this active ingredient

Compiled by Healify Pharmacy from published drug references. How we compile it →

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