CYP3A4 inhibitors inhibit Tegretol metabolism and can thus increase plasma Carbabeta levels. Drugs that have been shown, or would be expected, to increase plasma Carbabeta levels include aprepitant, cimetidine, ciprofloxacin, danazol, diltiazem, macrolides, erythromycin, troleandomycin, clarithromycin, fluoxetine, fluvoxamine, trazodone, olanzapine, loratadine, terfenadine, omeprazole, oxybutynin, dantrolene, isoniazid, niacinamide, nicotinamide, ibuprofen, propoxyphene, 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 Carbabeta-10,11 epoxide. Coadministration of inhibitors of human microsomal epoxide hydrolase may result in increased Carbabeta-10,11 epoxide plasma concentrations. Accordingly, the dosage of Tegretol should be adjusted and/or the plasma levels monitored when used concomitantly with loxapine, quetiapine, or valproic acid.
184.108.40.206 Related Substances
Test solution (a). Dissolve 60.0 mg of the substance to be examined in methanol R 2 and dilute to 20.0 mL with the same solvent. Sonicate. Dilute 10.0 mL of this solution to 20.0 mL with water R.
Test solution (b). Dilute 10.0 mL of test solution (a) to 50.0 mL with a mixture of equal volumes of methanol R 2 and water R.
Reference solution (a). Dissolve 7.5 mg of Carbabeta CRS, 7.5 mg of Carbabeta impurity A CRS, and 7.5 mg of iminodibenzyl R (impurity E) in methanol R 2 and dilute to 100.0 mL with the same solvent. Dilute 1.0 mL of this solution to 50.0 mL with a mixture of equal volumes of methanol R 2 and water R.
Reference solution (b). Dissolve 60.0 mg of Carbabeta CRS in methanol R 2 and dilute to 20.0 mL with the same solvent. Sonicate. Dilute 5.0 mL of this solution to 50.0 mL with a mixture of equal volumes of methanol R 2 and water R.
stationary phase: nitrile silica gel for chromatography R1 (10 μm).
Mobile phase tetrahydrofuran R, methanol R 2 , water R (3:12:85, v/v/v); to 1000 mL of this solution add 0.2 mL of anhydrous formic acid R and 0.5 mL of triethylamine R.
Flow rate: 2.0 mL/min.
Detection: a spectrophotometer at 230 nm.
Injection: 20 μL of test solution (a) and reference solution (a).
Run time: six times the retention time of Carbabeta.
Relative retention With reference to Carbabeta (retention time = about 10 min): impurity A = about 0.9; impurity E = about 5.1.
resolution: minimum 1.7 between the peaks due to Carbabeta and impurity A in the chromatogram obtained with reference solution (a).
impurities A and E: for each impurity, not more than the area of the corresponding peak in the chromatogram obtained with reference solution (a) (0.1%);
unspecified impurities: not more than the area of the peak due to Carbabeta in the chromatogram obtained with reference solution (a) (0.10%);
total: not more than five times the area of the peak due to Carbabeta in the chromatogram obtained with reference solution (a) (0.5%);
disregard limit: 0.5 times the area of the peak due to Carbabeta in the chromatogram obtained with reference solution (a) (0.05%).
Maximum 140 ppm.
Suspend 0.715 g in 20 mL of water R and boil for 10 min. Cool and dilute to 20 mL with water R. Filter through a membrane filter (nominal pore size: 0.8 μm). Dilute 10 mL of the filtrate to 15 mL with water R. This solution complies with the limit test for chlorides.
1.0 g complies with test C. Prepare the reference solution using 2 mL of lead standard solution (10 ppm Pb) R.
When Carbabeta is tested according to the general procedure not more than 0.5%, determined on 1.000 g by drying in an oven at 105°C for 2 h.
When Carbabeta is tested according to the general procedure not more than 0.1%, determined on 1.0 g.
Liquid chromatography (LC) as described in the test for related substances using injection test solution (b) and reference solution (b).
repeatability: reference solution (b).
Calculate the percentage content m/m of dried substance.
In an airtight container.
Specified impurities A, E.
Other detectable impurities (the following substances would, if present at a sufficient level, be detected by one or other of the tests in the monograph. They are limited by the general acceptance criterion for other/unspecified impurities and/or by the general monograph).
Substances for pharmaceutical use (2034).
It is therefore not necessary to identify these impurities for demonstration of compliance:
10,11-dihydro-5H-dibenzoazepine-5-carboxam >Carbabeta ),
5H-dibenzoazepine-5-carbonyl chloride (5-chlorocarbony liminostilbene).
Taking oxybutynin with Carbabeta will increase the level of Carbabeta in your body. This can cause side effects. Your doctor may monitor your blood levels of Carbabeta if you’re taking it with this drug.
Very common (10% or more): Allergic skin reactions, urticaria
Common (1% to 10%): Pruritus, rash, paresthesia
Uncommon (0.1% to 1%): Exfoliative dermatitis, erythroderma
Very rare (less than 0.01%): Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), photosensitivity, erythema multiforme, erythema nodosum, alterations in skin pigmentation, purpura, acne, sweating, alopecia, hirsutism, unusual bruising, pruritic and erythematous rashes, diaphoresis, onychomycosis, dermatitis
Frequency not reported: Psoriasiform eruption
Dangerous, sometimes fatal skin reactions (Stevens Johnson syndrome and toxic epidermal necrolysis), that can be caused by Carbabeta therapy are significantly more common in patients with the human leukocyte antigen (HLA) allele, HLA-B 1502. This allele occurs almost exclusively in patients with ancestry across broad areas of Asia, including South Asian Indians. Patients with ancestry from areas in which HLA-B 1502 is present should be screened for the HLA-B 1502 allele before starting treatment with Carbabeta. If these individuals test positive, Carbabeta should not be started unless the expected benefit clearly outweighs the increased risk of serious skin reactions. Patients who have been taking Carbabeta for more than a few months without developing skin reactions are at low risk of these events ever developing from Carbabeta. This is true for patients of any ethnicity or genotype, including patients who test positive for HLA-B 1502.
What is Carbabeta?
Carbabeta is an anticonvulsant. It works by decreasing nerve impulses that cause seizures and nerve pain, such as tregimenal neuralgia and diabetic neuropathy.
Carbabeta is also used to treat bipolar disorder.
Carbabeta may also be used for purposes not listed in this medication guide.
How should I take Carbabeta?
Take Carbabeta exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.
Swallow the extended-release tablet or capsule whole and do not crush, chew, or break it. Tell your doctor if you cannot swallow a pill whole.
The chewable tablet must be chewed before you swallow it.
Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).
It may take up to 4 weeks before your symptoms improve. Keep using the medication as directed and call your doctor promptly if this medicine seems to stop working as well in preventing your seizures.
You will need frequent medical tests.
Store at room temperature away from moisture, heat, and light.
Do not stop using Carbabeta suddenly, even if you feel fine. Stopping suddenly may cause increased seizures. Follow your doctor's instructions about tapering your dose.