Methotrexate Chloramphenicol

Azathioprine, chloramphenicol, colchicine, cyclophosphamide, cytarabine, 5-fluorodeoxyuridine, 5-fluorouracil, hydroxyurea, mercaptopurine, metformin, methotrexate, phenobarbital, phenytoin, primidone, proton pump inhibitors, pyrimethamine, sulfasalazine, and vinblastine... 

Reduction chloramphenicol cinchonidine cinchonine nitrazepam physostigmine pyrithione quinidine quinine benzoxaprofen chlortetracycline demeclocycline dithranol menadione mercaptopurine methotrexate nalidixic acid oxolinic acid... 

Drugs that may affect methotrexate include oral aminoglycosides, charcoal, chloramphenicol, folic acid, NSAIDs, PCNs, probenecid, salicylates, sulfonamides, TCN, trimethoprim. 

Cleavage at the benzylic position has likewise been observed in a variety of (hetero) aromatic derivatives such as chloramphenicol (Sch. 13) (31) or methotrexate (32). An important case is that of the decarboxylation of arylacetic or arylpropionic acids used as non-steroidal anti-inflammatory agents (Sch. 14) (33-35). 

These include mesalazine, metformin, NSAIDs, tetracyclines (except doxycycline and minocycline), chloramphenicol, lithium, methotrexate, chloroquine, fibrates, chlorpropamide and glibenclamide, Clinically, it is useful to measure urine output per hour or per 24 hours as a fall in urine output in the presence of adequate fluid intake often indicates or warns of some impairment of renal function. Furthermore, it is neither expensive nor time-consuming to perform a quick test for albumin, casts and red cells in the urine, and to measure pH. Creatinine clearance values are often used to determine the safe doses for several drugs (e.g. NSAIDs, ciclosporin). 

Clinically important, potentially hazardous interactions with allopurinol, bromelain, chloramphenicol, demeclocydine, doxycydine, erythromycin, imipenem/cilastatin, methotrexate, minocycline, oxytetracycline, sulfonamides, tetracycline... 

Noninterfering acetaminophen, caffeine, carbamazepine, chloramphenicol, desipramine, digoxin, disopyramide, ethosuximide, gentamicin, imipramine, Udocaine, methotrexate, N-acetylprocainamide, phenobarbital, phenytoin, primidone, procainamide, quinidine, saliqylic acid, theophyllhie, tobramycin, valproic acid... 

Noninterfering acetaminophen, acyclovir, allopurinol, amoxicillin, amphotericin B, am-picillin, aspirin, azlocillin, bendrofluazide, bumetanide, buprenorphine, carbenidllin, cefazolin, cefotaxime, cefoxitin, ceftazidime, cefuroxime, cephalexin, chlorambucil, chloramphenicol, chlordiazepoxide, chlorpheniramine, chlorpropamide, cyclophosphamide, cyclosporin, C5d arabine, daunorubicin, dextropropoxyphene, dihydrocodeine, domperidone, flucytosine, furosemide, gentamicin, griseofulvin, melphalan, methotrexate, metochlo-pramide, metronidazole, miconazole, nabilone, netilmicin, nicotinamide, nitrazepam, penicillin G, piperacillin, prednisolone, procarbeizine, prochlorperazine, riboflavin, rifampin, sulfamethoxazole, thioguanine, tobramycin, tolbutamide, trimethoprim... 

Noninterfering acetaminophen, allopurinol, amikacin, amoxapine, amytal, bretylium, caffeine, carbamazepine, carisoprodol, chloramphenicol, chlordiazepoxide, chlorpropamide, clonazepam, codeine, diazepeun, disop30 amide, droperidol, ethinamate, ethinamate, etho-suximide, fluphenazine, flurazepam, furosemide, gentamicin, haloperidol, hydrochlorothiazide, hydro yzine, ibuprofen, kanamycin, lidocaine, loxapine, meperidine, mepho-barbital, meprobamate, methaqualone, methotrexate, morphine, nafcUlin, naloxone, neomycin, perphenazine, phenacetin, phenobarbital, phenytoin, prazepam, primidone, procaine, propoxyphene, reserpine, salicylamide, salicylic acid, secobarbital, spironolactone, theophyUine, thiopental, thioridazine, tobramycin, valproic acid, verapeunil... 

Noninterfering acetaminophen, N-acetylprocainamide, amikacin, caffeine, carbamaze-pine, chloramphenicol, clonazepam, cyclosporine, diazepam, digoxin, disopyramide, etho-suximide, flurazepam, gentamicin, haloperidol, kanamycin, lidocaine, meprobamate, methapyriline, methaqualone, methotrexate, methyprylon, netilmicin, pentazocine, pentobarbital, phenobarbital, phenytoin, prazepam, primidone, procainamide, propranolol, quinidine, salicylic acid, secobarbital, streptomycin, theophylline, tobramycin, tocainide, valproic acid, vancomycin... 

Noninterfering acetaminophen, N-acetylprocainamide, amikacin, amitriptyline, amlodi-pine, carbamazepine, cefotaxime, ceftazidime, chloramphenicol, ciprofloxacin, cisapride, clindamycin, clonidine, codeine, cyclosporine, digoxin, diphenhydramine, disopyramide, ethosuximide, fluconazole, gentamicin, gentamicin, heparin, labetalol, levothyroxine, li-docaine, lithium, methotrexate, metronidazole, minoxidil, nafcillin, nifedipine, phenobar-bital, phenobarbital, phenytoin, phenytoin, primidone, procainamide, propranolol, quini-dine, ranitidine, salicylic acid, theophylline, tobramycin, tobramycin, valproic acid, warfarin... 

Animal studies suggested that the toxicity of methotrexate might be increased by the use of chloramphenicol, aminosalicylic acid, sodium saUcylate, sulfamethoxypyridazine, tetracycline or tolbutamide, but confirmation of this in man has only been seen with the salicylates, sulphonamides and possibly tetracycline. 

Some lists, reviews and books on interactions say that chloramphenicol, aminosalieylie aeid, sodium salieylate, sulfamethoxypyridazine, tetracycline or tolbutamide interact with methotrexate, apparently based largely on the preliminary findings of a study in which male mice were treated for 5 days with each of 4 doses of methotrexate (1.53 to 12.25 mg/kg intravenously) and immediately afterwards with non-toxic intraperitoneal doses of the drugs listed. These drugs were said to decrease the lethal dose and/or decrease the survival time of the mice That is to say, the toxicity of the methotrexate was increased. The reasons are not understood, but it is suggested that displacement of the methotrexate from its plasma protein binding sites could result in a rise in the levels of unbound and active methotrexate, and in the case of sodium salicylate to a decrease in renal clearance. 

These animal studies were done in 1968. Since then the elinieal importance of the interaction with salicylates has been eonfirmed (see Methotrexate + NSAIDs , p.649) there are a few eases involving sulfonamides , (p.643)) and there ate two isolated case report of an interaction with tetracyclines , (p.645), but there appears to be no direct clinical evidence of interactions between methotrexate and chloramphenicol or tolbutamide. The results of animal experiments cannot be applied directly and uncritically to man and it now seems probable that some of these suggested or alleged interactions are more theoretical than real. 

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