EQUETRO (carbamazepine) extended-release capsules
EQUETRO (carbamazepine) is a mood stabilizer available for oral administration as 100 mg, 200 mg, and 300 mg extended-release capsules of carbamazepine, USP. Carbamazepine is a white to off-white powder, practically insoluble in water and soluble in alcohol and in acetone. Its molecular weight is 236.27. The chemical name of carbamazepine is 5H-dibenz[b,f]azepine-5carboxamide
INDICATIONS AND USAGE
Acute Manic or Mixed Episodes associated with Bipolar I Disorder: EQUETRO is indicated for treatment of patients with acute manic or mixed episodes associated with bipolar I disorder
Pain of Trigeminal Neuralgia: EQUETRO is indicated in the treatment of the pain associated with trigeminal neuralgia. Beneficial results have also been reported in glossopharyngeal neuralgia. This drug is not a simple analgesic and should not be used for the relief of trivial aches or pains.
Epilepsy: EQUETRO is indicated for the treatment of partial seizures with complex symptomatology (e.g., psychomotor, temporal lobe), generalized tonic-clonic seizures (grand mal), and mixed seizure patterns, which include the seizure types listed here or other partial or generalized seizures.
Limitations of Usage
EQUETRO is not indicated for the treatment of absence seizures (petit mal).Carbamazepine has been associated with increased frequency of generalized convulsions in these patients.
Mechanism of Action
The mechanism of action of carbamazepine in the treatment of acute manic or mixed episodes associated with bipolar disorder is unclear.
DOSAGE AND ADMINISTRATION
Prior to initiating treatment with EQUETRO, test patients with ancestry in genetically at-risk populations for the presence of the HLA-B*1502 allele. The high resolution genotype test is positive if one or two HLA-B*1502 alleles are present. Avoid use of EQUETRO in patients testing positive for the allele, unless the benefit clearly outweighs the risk.
Complete pretreatment blood counts, including platelets and possibly reticulocytes and serum iron, should be obtained as a baseline. If a patient in the course of treatment exhibits low or decreased white blood cell or platelet counts, the patient should be monitored closely. Discontinuation of EQUETRO should be considered if any evidence of significant bone marrow depression develops.
Baseline and periodic evaluations of liver function, particularly in patients with a history of liver disease, must be performed during treatment with EQUETRO because liver damage may occur. Discontinue EQUETRO in cases of aggravated liver dysfunction or active liver disease.
Baseline and periodic eye examinations, including slit-lamp, funduscopy, and tonometry, are recommended since many phenothiazines and related drugs have been shown to cause eye changes.
Baseline and periodic complete urinalysis and BUN determinations are recommended for patients treated with this agent because of observed renal dysfunction.
Dosage for Acute Manic or Mixed Episodes Associated with Bipolar I Disorder: The recommended initial dose of EQUETRO is 200 mg administered twice daily. The dose may be increased by 200 mg per day to achieve optimal clinical response. Doses higher than 1600 mg per day have not been studied in mania associated with bipolar disorder.
Dosage for Pain of Trigeminal Neuralgia
Initial: On the first day, start with one 200 mg capsule once daily. This dose may be increased by up to 200 mg/day using increments of 100 mg every 12 hours only as needed to reach an effective and tolerated dose. Do not exceed a total daily dose of 1200 mg.
Maintenance: Control of pain can be maintained in most patients with 400 mg to 800 mg daily. However, some patients may be maintained on as little as 200 mg daily, while others may require as much as 1200 mg daily. At least once every 3 months throughout the treatment period, attempts should be made to reduce the dose to the minimum effective level or even to discontinue the drug.
Dosage for Epilepsy
Adults and Children over 12 Years of Age: The recommended initial dose is 200 mg administered twice daily. Increase in weekly increments of 200 mg a day, administered as an equally divided, twice daily dose, until an optimal response is obtained. Dosage generally should not exceed 500 mg twice daily in children 12 to 15 years old; 600 mg twice daily in children 15 to 18 years old; and 800 mg twice daily in adults.
Children Under 12 Years of Age: Ordinarily, optimal clinical response is achieved at daily doses below 35 mg/kg. No recommendation regarding the safety of EQUETRO for use at doses above 35 mg/kg/24 hours can be made.
Co-Administration with Other AEDs: EQUETRO may be used alone or with other AEDs. When added to existing AEDs, add EQUETRO gradually while the dosage(s) of other AEDs are maintained or gradually decreased. Potential drug interactions should be considered when using carbamazepine with other AEDs.
Switching from Immediate-Release Carbamazepine to EQUETRO
EQUETRO is an extended-release formulation for twice a day administration. When converting patients from immediate release carbamazepine to EQUETRO extended-release capsules, the same total daily mg dose of carbamazepine should be administered. Following conversion to EQUETRO, patients should be closely monitored for seizure control. Depending on the therapeutic response after conversion, the total daily dose may need to be adjusted within the recommended dosing instructions.
Discontinuation of EQUETRO
When discontinuing EQUETRO used for any indication, reduce the dose gradually and avoid abrupt discontinuation in order to decrease the risk of seizure.
Monitoring Serum Carbamazepine Concentration
Monitoring serum carbamazepine concentrations may be useful for dose selection, minimizing toxicity, and verifying drug compliance, especially in clinical conditions in which alterations in EQUETRO metabolism can occur (e.g., drug interactions). In pediatric patients treated with EQUETRO for epilepsy, if satisfactory clinical response has not been achieved, measure plasma levels to determine whether or not they are in the therapeutic range.
Swallow EQUETRO capsules whole or open and sprinkle the beads over food, such as a teaspoon of applesauce. Do not crush or chew EQUETRO capsules or the beads inside the capsule. EQUETRO can be taken with or without meals.
- Bone marrow depression.
- Known hypersensitivity to carbamazepine, such as anaphylaxis or serious hypersensitivity reaction.
- Known hypersensitivity to any of the tricyclic compounds (e.g., amitriptyline, desipramine, imipramine, protriptyline, and nortriptyline.) Hypersensitivity reactions include anaphylaxis and serious rash.
- Concomitant use of delavirdine or other non-nucleoside reverse transcriptase inhibitors that are substrates for CYP3A4. EQUETRO can substantially reduce the concentrations of these drugs through induction of CYP3A4. This can lead to loss of virologic response and possible resistance to these medications.
- Concomitant use of monoamine oxidase inhibitors (MAOIs). Before beginning treatment with EQUETRO, MAOIs should be discontinued for a minimum of 14 days. Concomitant use can cause serotonin syndrome.
- Concomitant use of nefazodone. This may result in insufficient plasma concentrations of nefazodone and its active metabolite to achieve a therapeutic effect.
WARNINGS AND PRECAUTIONS
Serious Dermatologic Reactions: Serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS), have been reported with carbamazepine treatment. These syndromes may be accompanied by mucous membrane ulcers, fever, or painful rash. Over 90% of carbamazepine-treated patients who experienced SJS/TEN developed these reactions within the first few months of treatment. The risk of these reactions is estimated to be about 1 to 6 per 10,000 new users in countries with mainly Caucasian populations. However, the risk in some Asian countries is estimated to be about 10 times higher. Discontinue EQUETRO if you suspect that the patient has a serious dermatologic reaction. If signs or symptoms suggest SJS/TEN, do not resume treatment with EQUETRO.
Aplastic Anemia and Agranulocytosis: Aplastic anemia and agranulocytosis have occurred in patients treated with carbamazepine. Data from a population-based case-control study suggest that the risk of developing these reactions is 5-8 times greater than in the general population. However, the overall risk of these reactions in the untreated general population is low, approximately six patients per one million population per year for agranulocytosis and two patients per one million population per year for aplastic anemia.
Drug Reaction with Eosinophilia and Systemic Symptoms/Multiorgan Hypersensitivity: Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also known as Multiorgan Hypersensitivity, have occurred with carbamazepine. Some of these events have been fatal or life-threatening. DRESS typically, although not exclusively, presents with fever, rash, lymphadenopathy, and/or facial swelling, in association with other organ system involvement, such as hepatitis, nephritis, hematologic abnormalities, myocarditis, or myositis sometimes resembling an acute viral infection. Eosinophilia is often present. This disorder is variable in its expression, and other organ systems not noted here may be involved. It is important to note that early manifestations of hypersensitivity (e.g., fever, lymphadenopathy) may be present even though rash is not evident. If such signs or symptoms are present, the patient should be evaluated immediately. EQUETRO should be discontinued if an alternative etiology for the signs or symptoms cannot be established.
Suicidal Behavior and Ideation: Antiepileptic drugs (AEDs), including EQUETRO, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.
Embryofetal Toxicity: EQUETRO can cause fetal harm when administered to a pregnant female. Pregnancy registries and epidemiological data suggest a potential association between the use of carbamazepine during pregnancy and major congenital malformations, including neural tube defects and malformations involving other body systems (e.g., craniofacial defects and cardiovascular malformations). These available data suggest that, compared with monotherapy, there may be a higher prevalence of teratogenic effects associated with the use of anticonvulsants in combination therapy.
Abrupt Discontinuation and Risk of Seizure: Do not discontinue EQUETRO abruptly, because of the risk of seizure and other withdrawal signs/symptoms. Patients with seizure disorder are at increased risk of developing seizure and status epilepticus with attendant hypoxia and threat to life. However, in the event of an allergic or hypersensitivity reaction, more rapid substitution of alternative therapy may be necessary.
Hyponatremia: Hyponatremia can occur as a result of treatment with EQUETRO. In many cases, the hyponatremia appears to be caused by the syndrome of inappropriate antidiuretic hormone secretion (SIADH). The risk of developing SIADH with EQUETRO treatment appears to be dose-related. Elderly patients and patients treated with diuretics are at greater risk of developing hyponatremia. Signs and symptoms of hyponatremia include headache, new or increased seizure frequency, difficulty concentrating, memory impairment, confusion, weakness, and unsteadiness, which can lead to falls. Consider discontinuing EQUETRO in patients with symptomatic hyponatremia.
Potential for Cognitive and Motor Impairment: EQUETRO has the potential to cause impairment in judgment, cognition, and motor function. Caution patients about operating hazardous machinery, including automobiles, until they are reasonably certain the EQUETRO does not affect them adversely.
Potential for Loss of Virologic Response to Non-nucleoside Reverse Transcriptase Inhibitors that are substrates for CYP3A4 with Concomitant Use of EQUETRO: Coadministration of EQUETRO with non-nucleoside reverse transcriptase inhibitors, including delavirdine, is contraindicated because it may lead to loss of virologic response and possible resistance. Through induction of CYP3A4, EQUETRO can markedly decrease the concentrations of these drugs.
Liver Damage: Hepatic effects, ranging from slight elevations in liver enzymes to rare cases of hepatic failure have been reported. In some cases, hepatic effects may progress despite discontinuation of the drug. In addition rare instances of vanishing bile duct syndrome have been reported. This syndrome consists of a cholestatic process with a variable clinical course ranging from fulminant to indolent, involving the destruction and disappearance of the intrahepatic bile ducts. Some, but not all, cases are associated with features that overlap with other immunoallergenic syndromes such as serious dermatologic reactions and Drug Reaction with Eosinophilia and Systemic Symptoms/Multiorgan Hypersensitivity.
AV Heart Block: AV heart block, including second and third degree block, have been reported following carbamazepine treatment. This occurred generally, but not solely, in patients with underlying EKG abnormalities or risk factors for conduction disturbances.
Hepatic Porphyria: The use of EQUETRO should be avoided in patients with a history of hepatic porphyria (e.g., acute intermittent porphyria, variegate porphyria, porphyria cutanea tarda). Acute attacks have been reported in such patients receiving carbamazepine therapy. EQUETRO administration has also been demonstrated to increase porphyrin precursors in rodents, a presumed mechanism for the induction of acute attacks of porphyria.
Increased Intraocular Pressure: Carbamazepine has mild anticholinergic activity. In patients with a history of increased intraocular pressure, consider assessing intraocular pressure before initiating treatment and periodically during therapy.
Monoamine Oxidase Inhibitors: Concomitant treatment with EQUETRO is contraindicated during use of an MAOI or within 14 days after discontinuing an MAOI. Concomitant use can cause serotonin syndrome.
Lithium: Concomitant administration of EQUETRO and lithium can increase the risk of neurotoxic adverse reactions. Consider reducing the dose of lithium or EQUETRO when using these drugs concomitantly.
Isoniazid: Concomitant use of carbamazepine and isoniazid has been reported to increase isoniazid-induced hepatotoxicity.
CNS Depressants: The concomitant use of EQUETRO and other CNS depressants can increase the risk of respiratory depression, profound sedation, hypotension, and syncope. CNS depressants include: alcohol, opioid analgesics, benzodiazepines, tricyclic antidepressants, sedative/hypnotics, anticonvulsants, antipsychotics, antihistamines, anticholinergics, alpha and beta blockers, general anesthetics, muscle relaxants, and illicit CNS depressants. Consider reducing the dose of CNS depressants or EQUETRO when using these drugs concomitantly.
Chloroquine and Mefloquine: The anti-malarial drugs chloroquine and mefloquine can antagonize the activity of EQUETRO.
Neuromuscular Blocking Agents: Resistance to the neuromuscular blocking action of the nondepolarizing neuromuscular blocking agents pancuronium, vecuronium, rocuronium and cisatracurium has occurred in patients chronically administered carbamazepine. Whether or not carbamazepine has the same effect on other nondepolarizing agents is unknown. Patients should be monitored closely for more rapid recovery from neuromuscular blockade than expected, and infusion rate requirements may be higher.
USE IN SPECIFIC POPULATIONS
Pregnancy: EQUETRO can cause fetal harm when administered to a pregnant female. Pregnancy registry and epidemiological data suggest a potential association between the use of carbamazepine during pregnancy and major congenital malformations, including neural tube defects and malformations involving other body systems (e.g., craniofacial defects and cardiovascular malformations). The available data are insufficient to identify an association with carbamazepine use and miscarriage
Lactation: Carbamazepine and its epoxide metabolite are present in human milk. Most infants with reported exposure to carbamazepine through human milk have not had adverse reactions; however, there are a few reported cases of hepatitis, regurgitations, poor weight gain, and vomiting in breastfed infants of females taking carbamazepine. There are no data on the effects of carbamazepine on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for EQUETRO and any potential adverse effects on the breastfed child from EQUETRO or from the underlying maternal condition.
Females and Males of Reproductive Potential
In females currently on EQUETRO who may become pregnant, assess the risks and benefits of continuing on EQUETRO and discuss with the patient if an alternative treatment should be considered. Dietary folic acid supplementation both prior to conception and during pregnancy should be recommended for patients using carbamazepine.
EQUETRO can increase metabolism of certain hormonal contraceptives (through CYP3A4 induction) such as oral and subdermal implant contraceptives, leading to significant lower plasma concentrations of hormones. This can cause contraceptive failure or breakthrough bleeding. Consider alternatives to oral and subdermal implant contraceptives that are significantly affected by induction of CYP3A4; or consider alternatives to EQUETRO.
Based on human and animal findings, EQUETRO may impair male fertility. Published clinical studies have reported a reduction in semen quality in males of reproductive potential with epilepsy that were treated with carbamazepine.
Lowest known lethal dose of carbamazepine: adults, greater than 60 grams (39-year-old man). Highest known doses survived: adults, 30 grams (31-year-old woman); children, 10 grams (6-year-old boy); small children, 5 grams (3-year-old girl).
Signs and Symptoms: The first signs and symptoms of carbamazepine overdose appear after 1 to 3 hours. Neuromuscular disturbances are the most prominent. Cardiovascular disorders are generally milder, and severe cardiac complications occur only when very high doses (greater than 60 grams) have been ingested.
Respiration: Irregular breathing, respiratory depression.
Cardiovascular System: Tachycardia, hypotension or hypertension, shock, conduction disorders.
Nervous System and Muscles: Impairment of consciousness ranging in severity to deep coma. Convulsions, especially in small children. Motor restlessness, muscular twitching, tremor, athetoid movements, opisthotonos, ataxia, drowsiness, dizziness, mydriasis, nystagmus, adiadochokinesia, ballism, psychomotor disturbances, dysmetria. Initial hyperreflexia, followed by hyporeflexia.
Gastrointestinal Tract: Nausea, vomiting.
Kidneys and Bladder: Anuria or oliguria, urinary retention.
Laboratory Findings: Isolated instances of overdosage have included leukocytosis, reduced leukocyte count, glycosuria, and acetonuria. ECG may show dysrhythmias.
Combined Poisoning: When alcohol, tricyclic antidepressants, barbiturates, or hydantoins are taken at the same time, the signs and symptoms of acute poisoning with carbamazepine may be aggravated or modified.
Management of Overdosage
For the most up to date information on management of EQUETRO overdose, contact the certified poison center for your area by calling 1-800-222-1222 (or at www.poison.org). In case of an overdose, provide supportive care, including close medical supervision and monitoring. Treatment should consist of those general measures employed in the management of overdosage with any drug. Consider the possibility of multiple drug overdose. Ensure an adequate airway, oxygenation, and ventilation. Monitor cardiac rhythm and vital signs. Use supportive and symptomatic measures.