Doxycycline Theophylline

Carbamazepine levels are increased by CYP3A4 inhibitors (cimetidine, macrolides, diltiazem, fluoxetine, ketoconazole, verapamil, valproate) levels are decreased by CYP3A4 inducers (cisplatin, doxorubicin, felbamate, phenobarbital, phenytoin, primidone, rifampin, theophylline). Carbamazepine may increase levels of clomipramine, phenytoin, and primidone and lithium toxicity may decrease levels of phenytoin, warfarin, oral contraceptives, doxycycline, theophylline, haloperidol, alprazolam, clozapine, ethosuximide, and valproate may interfere with other anticonvulsants. 

Drugs that may affect barbiturates include alcohol, charcoal, chloramphenicol, MAO inhibitors, rifampin, and valproic acid. Drugs that may be affected by barbiturates include acetaminophen, anticoagulants, beta blockers, carbamazepine, chloramphenicol, clonazepam, oral contraceptives, corticosteroids, digitoxin, doxorubicin, doxycycline, felodipine, fenoprofen, griseofulvin, hydantoins, methoxyflurane, metronidazole, narcotics, phenmetrazine, phenylbutazone, quinidine, theophylline, and verapamil. 

Acetaminophen Amiodarone Carbamazepine Cardiac glycosides Corticosteroids Dicumarol Disopyramide Doxycycline Estrogens Haloperidol Methadone Metyrapone Mexiletine Oral contraceptives Quinidine Theophylline Valproic acid Cyclosporine Dopamine Furosemide Levodopa Levonorgestrel Mebendazole Nondepolarizing muscle relaxant Phenothiazines Sulfonylureas... 

Rifampin is known to induce the hepatic microsomal enzymes that metabolize various drugs such as acetaminophen, oral anticoagulants, barbiturates, benzodiazepines, beta blockers, chloramphenicol, clofibrate, oral contraceptives, corticosteroids, cyclosporine, disopyramide, estrogens, hydantoins, mexiletine, quinidine, sulfones, sulfonylureas, theophyllines, tocainide, verapamil, digoxin, enalapril, morphine, nifedipine, ondansetron, progestins, protease inhibitors, buspirone, delavirdine, doxycycline, fluoroquinolones, losartan, macrolides, sulfonylureas, tacrolimus, thyroid hormones, TCAs, zolpidem, zidovudine, and ketoconazole. The therapeutic effects of these drugs may be decreased. 

Drugs that may interact with rifabutin include the following Anticoagulants, azole antifungal agents, benzodiazepines, beta blockers, buspirone, corticosteroids, cyclosporine, delavirdine, doxycycline, hydantoins, indinavir, rifamycins, losartan, macrolide antibiotics, methadone, morphine, nelfinavir, quinine, quinidine, theophylline, aminophylline, tricyclic antidepressants, and zolpidem. 

Tricyclic antidepressants, corticosteroids, coumarin anticoagulants, digitoxin, doxycycline, furosemide, oral contraceptives, quinidine, rifampin, theophylline, vitamin D... 

HA, mild pain Action Nonnarco tic analgesic w/ barbiturate Dose 1—2 tabs or caps PO q4-6h PRN i in renal/hepatic impair 4 g/24 h APAP max Caution [C, D, +] Alcoholic liver Dz Contra G6PD deficiency Disp Caps, Liq, tabs SE Drowsiness, dizziness, hangover effect Interactions T Effects OF benzodiazepines, opiate analgesics, sedatives/hypnotics, EtOH, methylphenidate hydrochloride i effects OF MAOIs, TCAs, corticosteroids, theophylline, OCPs, BBs, doxycycline EMS See Acetaminophen may impair coordination, monitor for depression concurrent EtOH use T CNS depression butalbital is habit forming... 

Fabre, J., Blanchard, P. and Rudhardt, M., Pharmacokinetics of ampicillin, cephal-othin and doxycycline in various tissues of the rat. Chemotherapy, 23, 129, 1977. Maza, A. et al., Influence of partial hepatectomy on theophylline pharmacokinetics in rats, J. Pharm. Sci., 85, 1133, 1996. 

Serum theophylline levels increased in two patients who were also given minocycline or tetracycline. Some controlled studies have shown both increases and decreases in theophylline clearance with doxycycline and tetracycline, with no significant changes overall. 

Seggev JS, Shefi M, Schey G, Farfel Z. Serum theophylline concenttations are not affected by coadministration of doxycycline. Ann Allergy (1986) 56, 156-7. 

Jonkman JHG, van der Boon WJV, Schoenmaker R, Holtkamp A, Hempenius J. No influence of doxycycline on theophylline pharmacokinetics. TherDrugMonit 9%5) 7, 92-4. 

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