Tegretal
Tegretal - General Information
An anticonvulsant used to control grand mal and psychomotor or focal seizures. Its mode of action is not fully understood, but some of its actions resemble those of phenytoin; although there is little chemical resemblance between the two compounds, their three-dimensional structure is similar. [PubChem]
Pharmacology of Tegretal
Tegretal, an anticonvulsant structurally similar to tricyclic antidepressants, is used to treat partial seizures, tonic-clonic seizures, pain of neurologic origin such as trigeminal neuralgia, and psychiatric disorders including manic-depressive illness and aggression due to dementia.
Tegretal for patients
PATIENT INFORMATION
Carbamazepine is used for the treatment of seizures. It also is used to treat certain types of nerve pain. Inform your physican if you are pregnant or nursing. Inform your physician if you have glaucoma. Do not take this medication with a monoamine oxidase inhibitor. This medication may cause dizziness, drowsiness, or blurred vision; use caution while driving or operating hazardous machinery. Do not stop taking carbamazepine without talking with your physician. Shake the suspension well before each use. This medication should be taken with meals to avoid stomach upset. Notify your physician if you develop unexplained fever, sore throat, unusual bleeding or bruising, or yellow eyes or skin.
Tegretal Interactions
Clinically meaningful drug interactions have occurred with concomitant medications and include, but are not limited to the following:
Agents Highly Bound to Plasma Protein
Carbamazepine is not highly bound to plasma proteins; therefore, administration of EQUETROTM to a patient taking another drug that is highly protein bound should not cause increased free concentrations of the other drug.
Agents that Inhibit Cytochrome P450 Isoenzymes and/or Epoxide Hydrolase
Carbamazepine is metabolized mainly by cytochrome P450 (CYP) 3A4 to the active carbamazepine 10,11-epoxide, which is further metabolized to the trans-diol by epoxide hydrolase. Therefore, the potential exists for interaction between carbamazepine and any agent that inhibits CYP3A4 and/or epoxide hydrolase. Agents that are CYP3A4 inhibitors that have been found, or are expected, to increase plasma levels of EQUETROTM are the following:
Acetazolamide, azole antifungals, cimetidine, clarithromycin(1), dalfopristin, danazol, delavirdine, diltiazem, erythromycin(1), fluoxetine, fluvoxamine, grapefruit juice, isoniazid, itraconazole, ketoconazole, loratadine, nefazodone, niacinamide, nicotinamide, protease inhibitors, propoxyphene, quinine, quinupristin, troleandomycin, valproate(1), verapamil, zileuton.
Thus, if a patient has been titrated to a stable dosage of EQUETROTM, and then begins a course of treatment with one of these CYP3A4 or epoxide hydrolase inhibitors, it is reasonable to expect that a dose reduction for EQUETROTM may be necessary.
Agents that Induce Cytochrome P450 Isoenzymes
Carbamazepine is metabolized by CYP3A4. Therefore, the potential exists for interaction between carbamazepine and any agent that induces CYP3A4. Agents that are CYP inducers that have been found, or are expected, to decrease plasma levels of EQUETROTM are the following:
Cisplatin, doxorubicin HCL, felbamate, rifampin, phenobarbital, Phenytoin(2), primidone, methsuximide, and theophylline
Thus, if a patient has been titrated to a stable dosage on EQUETROTM, and then begins a course of treatment with one of these CYP3A4 inducers, it is reasonable to expect that a dose increase for EQUETROTM may be necessary.
Agents with Decreased Levels in the Presence of Carbamazepine due to Induction of Cytochrome P450 Enzymes
Carbamazepine is known to induce CYP1A2 and CYP3A4. Therefore, the potential exists for interaction between carbamazepine and any agent metabolized by one (or more) of these enzymes. Agents that have been found, or are expected to have decreased plasma levels in the presence of EQUETROTM due to induction of CYP enzymes are the following:
Acetaminophen, alprazolam, amitriptyline, bupropion, buspirone, citalopram, clobazam, clonazepam, clozapine, cyclosporin, delavirdine, desipramine, diazepam, dicumarol, doxycycline, ethosuximide, felbamate, felodipine, glucocorticoids, haloperidol, itraconazole, lamotrigine, levothyroxine, lorazepam, methadone, midazolam, mirtazapine, nortriptyline, olanzapine, oral contraceptives(3), oxcarbazepine, Phenytoin(4), praziquantel, protease inhibitors, quetiapine, risperidone, theophylline, topiramate, tiagabine, tramadol, triazolam, valproate, warfarin(5), ziprasidone, and zonisamide.
Thus, if a patient has been titrated to a stable dosage on one of the agents in this category, and then begins a course of treatment with EQUETROTM, it is reasonable to expect that a dose increase for the concomitant agent may be necessary.
Agents with Increased Levels in the Presence of Carbamazepine:
EQUETROTM increases the plasma levels of the following agents:
Clomipramine HCl, Phenytoin(6), and primidone
Thus, if a patient has been titrated to a stable dosage on one of the agents in this category, and then begins a course of the treatment with EQUETROTM, it is reasonable to expect that a dose decrease for the concomitant agent may be necessary.
Pharmacological/Pharmacodynamic Interactions with Carbamazepine
Concomitant administration of carbamazepine and lithium may increase the risk of neurotoxic side effects.
Given the anticonvulsant properties of carbamazepine, EQUETROTM may reduce the thyroid function as has been reported with other anticonvulsants. Additionally, anti-malarial drugs, such as chloroquine and mefloquine, may antagonize the activity of carbamazepine.
Thus if a patient has been titrated to a stable dosage on one of the agents in this category, and then begins a course of treatment with EQUETROTM, it is reasonable to expect that a dose adjustment may be necessary.
Because of its primary CNS effect, caution should be used when EQUETROTM is taken with other centrally acting drugs and alcohol.
Tegretal Contraindications
Carbamazepine should not be used in patients with a history of previous bone marrow depression, hypersensitivity to the drug, or known sensitivity to any of the tricyclic compounds, such as amitriptyline, desipramine, imipramine, protriptyline and nortriptyline. Likewise, on theoretical grounds its use with monoamine oxidase inhibitors is not recommended. Before administration of carbamazepine, MAO inhibitors should be discontinued for a minimum of 14 days, or longer if the clinical situation permits.
Additional information about Tegretal
Tegretal Indication: For the treatment of epilepsy and pain associated with true trigeminal neuralgia.
Mechanism Of Action: Tegretal inhibits sustained repetitive firing by blocking use-dependent sodium channels. Pain relief is believed to be associated with blockade of synaptic transmission in the trigeminal nucleus and seizure control with reduction of post-tetanic potentiation of synaptic transmission in the spinal cord. Tegretal also possesses anticholinergic, central antidiuretic, antiarrhythmic, muscle relaxant, antidepressant (possibly through blockade of norepinephrine release), sedative, and neuromuscular-blocking properties.
Drug Interactions: Alprazolam Reduces the effect of the benzodiazepine
Aminophylline Increases or decreases the effect of theophylline
Amitriptyline The tricyclic increases the effect of carbamazepine
Anisindione Decreases the anticoagulant effect
Aprepitant This CYP3A4 inducer decreases the effect of aprepitant
Aripiprazole Decreases the effect of aripiprazole
Atorvastatin Decreases the effect of the statin
Atracurium Decreases the effect of muscle relaxant
Bupropion Decreases the effect of bupropion
Cimetidine Cimetidine increases the effect of carbamazepine
Clarithromycin The macrolide increases the effect of carbamazepine
Clozapine Decreases the effect of clozapine/hematologic toxicity
Cyclosporine Decreases the effect of cyclosporine
Delavirdine The anticonvulsant decreases the effect of delavirdine
Desipramine The tricyclic increases the effect of carbamazepine
Dicumarol Decreases the anticoagulant effect
Diltiazem Diltiazem increases the effect of carbamazepine
Dyphylline Increases or decreases the effect of theophylline
Valproic Acid Decreases the effect of valproic acid
Doxacurium Decreases the effect of muscle relaxant
Doxepin The tricyclic increases the effect of carbamazepine
Doxycycline The anticonvulsant decreases the effect of doxycycline
Dyphylline Increases or decreases the effect of theophylline
Erythromycin The macrolide increases the effect of carbamazepine
Ethinyl Estradiol This product might cause a slight decrease of contraceptive effect
Felbamate Decreased effect of both products
Felodipine Decreases the effect of felodipine
Fluconazole Fluconazole increases the effect of carbamazepine
Fluoxetine Fluoxetine increases the effect of carbamazepine
Fluvoxamine Fluvoxamine increases the effect of carbamazepine
Gallamine Triethiodide Decreases the effect of muscle relaxant
Gefitinib This CYP3A4 inducer may reduce gefitinib plasma concentrations and pharmacological effects
Haloperidol Decreases the effect of haloperidol
Imatinib Decreases levels of imatinib
Imipramine The tricyclic increases the effect of carbamazepine
Indinavir Indinavir increases the effect and toxicity of carbamazepine
Isoniazid Tegretal effect is increased as is isoniazid toxicity
Isotretinoin Isotretinoine decreases the effect of carbamazepine
Itraconazole The imidazole increases the effect of carbamazepine
Josamycin The macrolide increases the effect of carbamazepine
Ketoconazole The imidazole increases the effect of carbamazepine
Lamotrigine Decreases the effect of lamotrigine
Levetiracetam This association may increase the risks of carbamazepine toxicity
Lovastatin Decreases the effect of the statin
Mestranol This product may cause a slight decrease of contraceptive effect
Methadone Decreases levels of methadone
Methylphenidate Tegretal could reduce the effect of methylphenidate
Metocurine Decreases the effect of muscle relaxant
Metronidazole Metronidazole increases the effect of carbamazepine
Midazolam Reduces the effect of the benzodiazepine
Mivacurium Decrease the effect of muscle relaxant
Nefazodone Nefazodone increases the effect of carbamazepine
Acenocoumarol Decreases the anticoagulant effect
Norethindrone This product may cause a slight decrease of contraceptive effect
Nortriptyline The tricyclic increases the effect of carbamazepine
Oxtriphylline Increases or decreases the effect of theophylline
Oxybutynin Oxybutynin may cause carbamazepine toxicity
Pancuronium Decreases the effect of muscle relaxant
Praziquantel Markedly lower praziquantel levels
Propoxyphene Propoxyphene increases the effect of carbamazepine
Quinupristin This combination presents an increased risk of toxicity
Risperidone Decreases the effect of risperidone
Ritonavir Ritonavir increases the effect of carbamazepine
Sertraline Sertraline increases the effect of carbamazepine
Simvastatin Decreases the effect of the statin
Sunitinib Possible decrease in sunitinib levels
Telithromycin Telithromycin may possibly increase this agent effect/toxicity
Theophylline Increases or decreases the effect of theophylline
Theophylline Increases or decreases the effect of theophylline
Ticlopidine Ticlopidine increases the effect of carbamazepine
Topiramate Tegretal may reduce levels of topiramate
Tramadol Reduces the efficacy of tramadol
Troleandomycin The macrolide increases the effect of carbamazepine
Tubocurarine Decreases the effect of muscle relaxant
Vecuronium Decreases the effect of muscle relaxant
Verapamil Verapamil increases the effect of carbamazepine
Voriconazole Decreases the effect of voriconazole
Warfarin Decreases the anticoagulant effect
Ziprasidone Increases the effect and toxicity of ziprasidone
Danazol Danazol increases the effect of carbamazepine
Levonorgestrel Decreases the contraceptive effect
Food Interactions: Avoid alcohol.
Take with food, increases availability and reduces irritation.
Grapefruit can significantly increase serum levels of this product.
Avoid taking grapefruit or grapefruit juice throughout treatment.
Generic Name: Carbamazepine
Synonyms: Carbamezepine
Drug Category: Analgesics; Antimanic Agents; Anticonvulsants
Drug Type: Small Molecule; Approved; Investigational
Other Brand Names containing Carbamazepine: Apo-Carbamazepine; Atretol; Biston; Calepsin; Carbamazepen; Carbatrol; Carbazepine; Carbelan; Epitol; Equetro; Finlepsin; Karbamazepin; Lexin; Neurotol; Novo-Carbamaz; Nu-Carbamazepine; Sirtal; Stazepin; Stazepine; Taro-Carbamazepine; Taro-Carbamazepine Cr; Tegretal; Tegretol; Tegretol Chewtabs; Tegretol Cr; Tegretol-Xr; Telesmin; Teril; Timonil;
Absorption: Not Available
Toxicity (Overdose): Mild ingestions cause vomiting, drowsiness, ataxia, slurred speech, nystagmus, dystonic reactions, and hallucinations. Severe intoxications may produce coma, seizures, respiratory depression, and hypotension
Protein Binding: Carbamazepine in blood is 76% bound to plasma proteins.
Biotransformation: Hepatic
Half Life: 25-65 hours
Dosage Forms of Tegretal: Tablet, extended release Oral
Tablet Oral
Suspension Oral
Chemical IUPAC Name: benzo[b][1]benzazepine-11-carboxamide
Chemical Formula: C15H12N2O
Carbamazepine on Wikipedia: https://en.wikipedia.org/wiki/Carbamazepine
Organisms Affected: Humans and other mammals
