Vincristine Phenytoin

The use of stavudine in combination with isoniazid, vincristine, phenytoin and ethambutol may increase the risk of peripheral neuropathy and pancreatitis. It competes with zidovudine for phosphorylation and should not be used in combination. 

Vincristine Phenytoin Reduced effect of phenytoin interaction poorly documented Unknown... 

Additive bone marrow depressive effects occur when the miotic inhibitor drugs are administered with other anti-neoplastic dragp or radiation therapy. Administration of vincristine with digoxin results in a decreased therapeutic effect of tlie digoxin and decreased plasma digoxin levels. There is a decrease in serum concentrations of phenytoin when administered widi vinblastine... 

Aprepitant may be affected by paroxetine, CYP2C9 substrates (eg, phenytoin, tolbutamide, warfarin), CYP3A4 substrates (eg, alprazolam, cisapride, dexamethasone, docetaxel, etoposide, ifosfamide, imatinib, irinotecan, methylprednisolone, midazolam, paclitaxel, pimozide, triazolam, vinblastine, vincristine, vinorelbine), and oral contraceptives. 

Drugs that may interact with zalcitabine include antacids, chloramphenicol, cisplatin, dapsone, didanosine, disulfiram, ethionamide, glutethimide, gold, hydralazine, iodoquinol, isoniazid, metronidazole, nitrofurantoin, phenytoin, ribavirin, vincristine, cimetidine, metoclopramide, amphotericin, aminoglycosides, foscarnet, antiretroviral nucleoside analogs, pentamidine, and probenecid. 

VINCA ALKALOIDS - VINBLASTINE, VINCRISTINE 1. ANTIBIOTICS-rifampicin 2. ANTICANCER AND IMMUNOMODULATING DRUGS - dexamethasone 3. ANTIDEPRESSANTS-St John s wort 4. ANTI EPILEPTICS -carbamazepine, phenobarbital, phenytoin 1 of plasma concentrations of vinblastine and vincristine, with risk of inadequate therapeutic response. Reports of 1 AUC by 40% and elimination half life by 35%, and t clearance by 63%, in patients with brain tumours taking vincristine, which could lead to dangerously inadequate therapeutic responses Due to induction of CYP3A4-mediated metabolism Monitor for clinical efficacy, and t dose of vinblastine and vincristine as clinically indicated in the latter case, monitor clinically and radiologically for clinical efficacy in patients with brain tumours and t dose to obtain desired response... 

Clinically important, potentially hazardous interactions with alprazolam, astemizole, carbamazepine, cisapride, clarithromycin, dexamethasone, diltiazem, docetaxel, ifosfamide, imatinib, irinotecan, itraconazole, ketoconazole, methylprednisolone, midazolam, nefazodone, oral contraceptives, paroxetine, phenytoin, pimozide, rifampin, ritonavir, terfenadine, tolbutamide, trabectedin, troleandomycin, vinblastine, vincristine, warfarin... 

Clinically important, potentially hazardous interactions with abacavir, atorvastatin, bepridil, bupropion, carbamazepine, clarithromycin, cyclosporine, dexamethasone, digoxin, felodipine, fluticasone propionate, fosamprenavir, itraconazole, ketoconazole, lovastatin, methadone, midazolam, nicardipine, nifedipine, phenobarbital, phenytoin, rifabutin, simvastatin, sirolimus, St John s wort, systemic lidocaine, tacrolimus, tenofovir, trazodone, vinblastine, vincristine, voriconazole, warfarin, zidovudine... 

In most cases the mechanism is not known. Stimulators of vasopressin secretion include vincristine, cyclophosphamide, tricyclic antidepressants, nicotine, epinephrine, and high doses of morphine. Lithium, which inhibits the renal effects of vasopressin, also enhances vasopressin secretion. Inhibitors of vasopressin secretion include ethanol, phenytoin, low doses of morphine, glucocorticoids, fluphenazine, haloperidol, promethazine, oxilorphan, and butorphanol. Carba-mazepine has a renal action to produce antidiuresis in patients with central diabetes insipidus but actually inhibits vasopressin secretion via a central action. 

Phenytoin followed by Carbamazepine Vincristine Cytarabine Hydroxycarbamide Daunorubicin Methotrexate Tioguanine Cyclophosphamide Carmustine Stage iV T-ceii iymphoma Phenytoin faiied to reach therapeutic ieveis and so was substituted with carbamazepine. Chemotherapy caused carbamazepine levels to drop below therapeutic levels resulting in seizures, increasing the dose from 30 to 50 mg/kg per day prevented subtherapeutic ieveis. 8... 

Phenytoin Methotrexate Mercaptopurine Vincristine Acute lymphoblastic leukaemia Phenytoin levels dropped from 19.8 micrograms/mL on the day before chemotherapy to 3.6 micrograms/mL on the 6th day of chemotherapy. 9... 

Carbamazepine andphenytoin appear to reduce the plasma levels of vincristine, and may reduce its efficacy. A number of case reports have described reduced phenytoin levels in patients receiving chemotherapy including vinca alkaloids. 

These enzyme-inducing antiepileptics increase the metabolism of vincristine by the cytochrome P450 isoenzyme CYTBA4. However, in vitro studies have shown that phenytoin may potentiate the antineoplastic (antimitotic) effects of the vinca alkaloids. Thus, further study is required to determine the overall effect of phenytoin on the efficacy and toxicity of vincristine and other vinca alkaloids. Carbamazepine would be expected to reduce the efficacy of vincristine. 

Ganapathi R, Hercbeigs Grabowski D, Ford J. Selective enhancement of vincristine cytotoxicity in multidrug-resistant tumor cells by dilantin (phenytoin). Cancer Res (1993) 53, 3262-5. Correction, ibid 6079. 

Simultaneous acetaminophen, aldosterone, allopiudnoL amitriplyline, caffeine, calcitriol, cephalothin, chlordiazepoxide, chlorothiazide, corticosterone, cortisone, dexamethasone, diazepam, ephedrine, ethinyl estradiol, furosemide, hydrocortisone, ibuprofen, imipra-mine, indomethacin, mechlorethamine, methylprednisone, metolazone, nandrolone, naproxen, phenacetin, phenobarbital, phenytoin, probenecid, progesterone, propranolol, sulfasalazine, testosterone, theophylline, vincristine... 

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