Carbamazepine 400 mg Tablet, Film Coated, Extended Release, 100-count — NDC 62332-422-31 (Billing 62332-0422-31)

WARNINGS Serious Dermatologic Reactions Serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS), have been reported with carbamazepine extended-release tablets treatment. The risk of these events 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.

Carbamazepine extended-release tablets should be discontinued at the first sign of a rash, unless the rash is clearly not drug related. If signs or symptoms suggest SJS/TEN, use of this drug should not be resumed, and alternative therapy should be considered. SJS/TEN and HLA-B*1502 Allele Retrospective case-control studies have found that in patients of Chinese ancestry there is a strong association between the risk of developing SJS/TEN with carbamazepine treatment and the presence of an inherited variant of the HLA-B gene, HLA-B*1502.

The occurrence of higher rates of these reactions in countries with higher frequencies of this allele suggests that the risk may be increased in allele-positive individuals of any ethnicity. Across Asian populations, notable variation exists in the prevalence of HLA-B*1502. Greater than 15% of the population is reported positive in Hong Kong, Thailand, Malaysia, and parts of the Philippines, compared to about 10% in Taiwan and 4% in North China.

South Asians, including Indians, appear to have intermediate prevalence of HLA-B*1502, averaging 2% to 4%, but higher in some groups. HLA-B*1502 is present in less than 1% of the population in Japan and Korea. HLA-B*1502 is largely absent in individuals not of Asian origin (e.g., Caucasians, African-Americans, Hispanics, and Native Americans).

Prior to initiating carbamazepine extended-release tablets therapy, testing for HLA-B*1502 should be performed in patients with ancestry in populations in which HLA-B*1502 may be present. In deciding which patients to screen, the rates provided above for the prevalence of HLA-B*1502 may offer a rough guide, keeping in mind the limitations of these figures due to wide variability in rates even within ethnic groups, the difficulty in ascertaining ethnic ancestry, and the likelihood of mixed ancestry. Carbamazepine extended-release tablets should not be used in patients positive for HLA-B*1502 unless the benefits clearly outweigh the risks.

Tested patients who are found to be negative for the allele are thought to have a low risk of SJS/TEN (see BOXED WARNING and PRECAUTIONS, Laboratory Tests). Over 90% of carbamazepine extended-release tablets treated patients who will experience SJS/TEN have this reaction within the first few months of treatment. This information may be taken into consideration in determining the need for screening of genetically at-risk patients currently on carbamazepine extended-release tablets.

The HLA-B*1502 allele has not been found to predict risk of less severe adverse cutaneous reactions from carbamazepine extended-release tablets, such as maculopapular eruption (MPE) or to predict Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). Limited evidence suggests that HLA-B*1502 may be a risk factor for the development of SJS/TEN in patients of Chinese ancestry taking other antiepileptic drugs associated with SJS/TEN, including phenytoin. Consideration should be given to avoiding use of other drugs associated with SJS/TEN in HLA-B*1502 positive patients, when alternative therapies are otherwise equally acceptable.

Hypersensitivity Reactions and HLA-A*3101 Allele Retrospective case-control studies in patients of European, Korean, and Japanese ancestry have found a moderate association between the risk of developing hypersensitivity reactions and the presence of HLA-A*3101, an inherited allelic variant of the HLA-A gene, in patients using carbamazepine. These hypersensitivity reactions include SJS/TEN, maculopapular eruptions, and Drug Rea… [Excerpted — this section continues on DailyMed.]

ADVERSE REACTIONS If adverse reactions are of such severity that the drug must be discontinued, the physician must be aware that abrupt discontinuation of any anticonvulsant drug in a responsive epileptic patient may lead to seizures or even status epilepticus with its life-threatening hazards. The most severe adverse reactions have been observed in the hemopoietic system and skin (see BOXED WARNING), the liver, and the cardiovascular system. The most frequently observed adverse reactions, particularly during the initial phases of therapy, are dizziness, drowsiness, unsteadiness, nausea, and vomiting.

To minimize the possibility of such reactions, therapy should be initiated at the lowest dosage recommended. The following additional adverse reactions have been reported: Hemopoietic System: Aplastic anemia, agranulocytosis, pancytopenia, bone marrow depression, thrombocytopenia, leukopenia, leukocytosis, eosinophilia, acute intermittent porphyria, variegate porphyria, porphyria cutanea tarda. Skin: TEN and SJS (see BOXED WARNING), Acute Generalized Exanthematous Pustulosis (AGEP), pruritic and erythematous rashes, urticaria, photosensitivity reactions, alterations in skin pigmentation, exfoliative dermatitis, erythema multiforme and nodosum, purpura, aggravation of disseminated lupus erythematosus, alopecia, diaphoresis, onychomadesis and hirsutism.

In certain cases, discontinuation of therapy may be necessary. Cardiovascular System: Congestive heart failure, edema, aggravation of hypertension, hypotension, syncope and collapse, aggravation of coronary artery disease, arrhythmias and AV block, thrombophlebitis, thromboembolism (e.g., pulmonary embolism), and adenopathy or lymphadenopathy. Some of these cardiovascular complications have resulted in fatalities.

Myocardial infarction has been associated with other tricyclic compounds. Liver: Abnormalities in liver function tests, cholestatic and hepatocellular jaundice, hepatitis, very rare cases of hepatic failure. Pancreatic: Pancreatitis.

Respiratory System: Pulmonary hypersensitivity characterized by fever, dyspnea, pneumonitis, or pneumonia. Genitourinary System: Urinary frequency, acute urinary retention, oliguria with elevated blood pressure, azotemia, renal failure, and impotence. Albuminuria, glycosuria, elevated BUN, and microscopic deposits in the urine have also been reported.

There have been rare reports of impaired male fertility and/or abnormal spermatogenesis. Testicular atrophy occurred in rats receiving carbamazepine extended-release tablets orally from 4 to 52 weeks at dosage levels of 50 to 400 mg/kg/day. Additionally, rats receiving carbamazepine extended-release tablets in the diet for 2 years at dosage levels of 25, 75, and 250 mg/kg/day had a dose-related incidence of testicular atrophy and aspermatogenesis.

In dogs, it produced a brownish discoloration, presumably a metabolite, in the urinary bladder at dosage levels of 50 mg/kg and higher. Relevance of these findings to humans is unknown. Nervous System: Dizziness, drowsiness, disturbances of coordination, confusion, headache, fatigue, blurred vision, visual hallucinations, transient diplopia, oculomotor disturbances, nystagmus, speech disturbances, abnormal involuntary movements, peripheral neuritis and paresthesias, depression with agitation, talkativeness, tinnitus, hyperacusis, neuroleptic malignant syndrome.

There have been reports of associated paralysis and other symptoms of cerebral arterial insufficiency, but the exact relationship of these reactions to the drug has not been established. Isolated cases of neuroleptic malignant syndrome have been reported both with and without concomitant use of psychotropic drugs. Digestive System: Nausea, vomiting, gastric distress and abdominal pain, diarrhea, constipation, anorexia, and dryness of the mouth and pharynx, including glossitis and stomatitis.

Eyes: Scattered punctate cortical lens opacities, increased intraocular pressure (see WARNINGS, General) a… [Excerpted — this section continues on DailyMed.]

Drug Interactions Clinically meaningful drug interactions have occurred with concomitant medications and include (but are not limited to) the following: Agents That May Affect Carbamazepine Plasma Levels When carbamazepine is given with drugs that can increase or decrease carbamazepine levels, close monitoring of carbamazepine levels is indicated and dosage adjustment may be required. Agents That Increase Carbamazepine Levels CYP3A4 inhibitors inhibit carbamazepine metabolism and can thus increase plasma carbamazepine levels.

Drugs that have been shown, or would be expected, to increase plasma carbamazepine levels include aprepitant, cimetidine, ciprofloxacin, danazol, diltiazem, macrolides (e.g., erythromycin, clarithromycin), fluoxetine, fluvoxamine, trazodone, omeprazole, oxybutynin, isoniazid, niacinamide (nicotinamide), azoles (e.g., ketaconazole, itraconazole, fluconazole, voriconazole), acetazolamide, verapamil, ticlopidine, grapefruit juice, and protease inhibitors. Human microsomal epoxide hydrolase has been identified as the enzyme responsible for the formation of the 10,11-transdiol derivative from carbamazepine-10,11 epoxide.

Coadministration of inhibitors of human microsomal epoxide hydrolase may result in increased carbamazepine-10,11 epoxide plasma concentrations. Accordingly, the dosage of carbamazepine extended-release tablets should be adjusted and/or the plasma levels monitored when used concomitantly with loxapine, quetiapine, valproic acid, or brivaracetam. Agents That Decrease Carbamazepine Levels CYP3A4 inducers can increase the rate of carbamazepine metabolism.

Drugs that have been shown, or that would be expected, to decrease plasma carbamazepine levels include cisplatin, doxorubicin HCl, felbamate, fosphenytoin, rifampin, phenobarbital, phenytoin, primidone, methsuximide, theophylline, aminophylline. Effect of Carbamazepine Extended-Release Tablets on Plasma Levels of Concomitant Agents Decreased Levels of Concomitant Medications Carbamazepine extended-release tablet is a potent inducer of hepatic 3A4 and is also known to be an inducer of CYP1A2, 2B6, 2C8/9/19, and may therefore reduce plasma concentrations of co-medications mainly metabolized by CYP1A2, 2B6, 2C8/9/19, and 3A4, through induction of their metabolism.

When used concomitantly with carbamazepine extended-release tablets, monitoring of concentrations or dosage adjustment of these agents may be necessary: • When carbamazepine is added to aripiprazole, the aripiprazole dose should be doubled. Additional dose increases should be based on clinical evaluation. If carbamazepine is later withdrawn, the aripiprazole dose should be reduced. • When carbamazepine is used with tacrolimus, monitoring of tacrolimus blood concentrations and appropriate dosage adjustments are recommended. • The use of concomitant strong CYP3A4 inducers, such as carbamazepine should be avoided with temsirolimus.

If patients must be coadministered carbamazepine with temsirolimus, an adjustment of temsirolimus dosage should be considered. • The use of carbamazepine with lapatinib should generally be avoided. If carbamazepine is started in a patient already taking lapatinib, the dose of lapatinib should be gradually titrated up. If carbamazepine is discontinued, the lapatinib dose should be reduced. • Concomitant use of carbamazepine with nefazodone results in plasma concentrations of nefazodone and its active metabolite insufficient to achieve a therapeutic effect.

Coadministration of carbamazepine with nefazodone is contraindicated (see CONTRAINDICATIONS). • Monitor concentrations of valproate when carbamazepine extended-release tablet is introduced or withdrawn in patients using valproic acid. In addition, carbamazepine extended-release tablet causes, or would be expected to cause, decreased levels of the following drugs, for which monitoring of concentrations or dosage adjustment may be necessary: acetaminophen, albendazole, alprazolam, aprepitant, buprenorphone, bupropio… [Excerpted — this section continues on DailyMed.]

Other Drug Interactions • Cyclophosphamide is an inactive prodrug and is converted to its active metabolite in part by CYP3A. The rate of metabolism and the leukopenic activity of cyclophosphamide are reportedly increased by chronic coadministration of CYP3A4 inducers. There is a potential for increased cyclophosphamide toxicity when coadministered with carbamazepine. • Concomitant administration of carbamazepine and lithium may increase the risk of neurotoxic side effects. • Concomitant use of carbamazepine with olanzapine, dantrolene, or ibuprofen may increase plasma carbamazepine levels. • Concomitant use of carbamazepine and isoniazid has been reported to increase isoniazid-induced hepatotoxicity. • Alterations of thyroid function have been reported in combination therapy with other anticonvulsant medications. • Concomitant use of carbamazepine extended-release tablets with hormonal contraceptive products (e.g., oral, and levonorgestrel subdermal implant contraceptives) may render the contraceptives less effective because the plasma concentrations of the hormones may be decreased.

Breakthrough bleeding and unintended pregnancies have been reported. Alternative or back-up methods of contraception should be considered. • 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 non-depolarizing agents is unknown.

Patients should be monitored closely for more rapid recovery from neuromuscular blockade than expected, and infusion rate requirements may be higher. • Concomitant use of carbamazepine with rivaroxaban, apixaban, dabigatran, and edoxaban (direct acting oral anticoagulants) is expected to result in decreased plasma concentrations of these anticoagulants that may be insufficient to achieve the intended therapeutic effect. In general, coadministration of carbamazepine with rivaroxaban, apixaban, dabigatran, and edoxaban should be avoided.

PRECAUTIONS General Before initiating therapy, a detailed history and physical examination should be made. Carbamazepine extended-release tablets should be used with caution in patients with a mixed seizure disorder that includes atypical absence seizures, since in these patients carbamazepine extended-release tablet has been associated with increased frequency of generalized convulsions (see INDICATIONS AND USAGE). Therapy should be prescribed only after critical benefit-to-risk appraisal in patients with a history of cardiac conduction disturbance, including second- and third-degree AV heart block; cardiac, hepatic, or renal damage; adverse hematologic or hypersensitivity reaction to other drugs, including reactions to other anticonvulsants; or interrupted courses of therapy with carbamazepine extended-release tablets.

AV heart block, including second- and third-degree block, have been reported following carbamazepine extended-release tablets treatment. This occurred generally, but not solely, in patients with underlying EKG abnormalities or risk factors for conduction disturbances. Hepatic effects, ranging from slight elevations in liver enzymes to rare cases of hepatic failure have been reported (see ADVERSE REACTIONS and PRECAUTIONS, Laboratory Tests).

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 multiorgan hypersensitivity (DRESS syndrome) and serious dermatologic reactions. As an example, there has been a report of vanishing bile duct syndrome associated with SJS and in another case an association with fever and eosinophilia. Information for Patients Patients should be informed of the availability of a Medication Guide, and they should be instructed to read the Medication Guide before taking carbamazepine extended-release tablets.

Patients should be made aware of the early toxic signs and symptoms of a potential hematologic problem, as well as dermatologic, hypersensitivity or hepatic reactions. These symptoms may include, but are not limited to, fever, sore throat, rash, ulcers in the mouth, easy bruising, lymphadenopathy and petechial or purpuric hemorrhage, and in the case of liver reactions, anorexia, nausea/vomiting, or jaundice. The patient should be advised that, because these signs and symptoms may signal a serious reaction, that they must report any occurrence immediately to a physician.

In addition, the patient should be advised that these signs and symptoms should be reported even if mild or when occurring after extended use. Patients should be advised that serious skin reactions have been reported in association with carbamazepine extended-release tablets. In the event a skin reaction should occur while taking carbamazepine extended-release tablets, patients should consult with their physician immediately (see WARNINGS).

Patients should be advised that anaphylactic reactions and angioedema may occur during treatment with carbamazepine extended-release tablets (see WARNINGS). Advise patients to immediately report signs and symptoms suggesting angioedema (swelling of the face, eyes, lips, or tongue, or difficulty in swallowing or breathing) and to stop taking the drug until they have consulted with their healthcare provider. Patients, their caregivers, and families should be counseled that AEDs, including carbamazepine extended-release tablets, may increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or tho… [Excerpted — this section continues on DailyMed.]

DRUG ABUSE AND DEPENDENCE No evidence of abuse potential has been associated with carbamazepine extended-release tablets, nor is there evidence of psychological or physical dependence in humans.