Oral contraceptives drug interactions

Fazio A. Oral contraceptive drug interactions important considerations. South Med J 1991 84 997-1002. 

Back DJ, Grimmer SF, Orme ML, Proudlove C, Mann RD, Breckemidge AM. Evaluation of Committee on Safety of Medicines yellow card reports on oral contraceptive-drug interactions with anticonvulsants and antibiotics. Br J Qin Pharmacol 1988 25(5) 527-32. 

Saw palmetto (cabbage palm, fan palm, scrub palm) Serenoa repens %mptoms of benign prostatic hyperplasia Generally well-tolerated occasional gastrointestinal effects May interact with hormones such as oral contraceptive drugs and hormone replacement therapy. 

D Arcy, RF. (1986) Drug Interactions with oral contraceptives. Drug Intell Clin Pharm 20 353-362. 

May interact with hormones such as oral contraceptive drugs and hormone replacement therapy. 

Drug Interactions Carbamazepine induces the hepatic metabolism of many drugs, including other antiepileptic drugs, antipsychotics, some antidepressants, oral contraceptives, and... 

Cite important drug interactions with oral contraceptives. 

Ethinyl estradiol is metabolized in the liver via the cytochrome P-450 system. It is metabolized primarily via CYP450 3A4. When reviewing drug interactions of oral contraceptives, it is important to keep in mind that antibiotic administration during contraceptive use may decrease the efficacy of many combined contraceptives. Refer to Table 45-4 for a list of common drug interactions seen with oral contraceptives.1,31... 

Dickinson BD, Altman RD, Nielsen NH, Sterling ML Council on Scientific Affairs, American Medical Association Drug interactions between oral contraceptives and antibiotics. Obstet Gynecol 2001 98 853-860. 

Numerous potential drug interactions are possible clinically significant drug interactions with oral contraceptives, warfarin, and oral dexametha-sone have been described. 

Interactions of Oral Contraceptives (PCs) with Other Drugs... 

Drug-drug interactions are often more problematic with carbamazepine than other mood stabilizers. Carbamazepine increases the activity of certain liver enzymes. Because these enzymes metabolize and eliminate medications and other substances introduced to the body, carbamazepine therapy can decrease the blood level and thereby reduce the effectiveness of itself (a phenomenon called autoinduction) and other medications that are metabolized by these enzymes. It is not unusual to find that the dose of carbamazepine must be increased after several weeks, because it has increased its own elimination. Other medications may likewise be less effective. Of particular concern are the oral contraceptives, Depo-Provera, and protease inhibitors used for the treatment of HI V+ patients. Oral contraceptives often require an increase in dose. 

Drugs that may interact with folic acid include aminosalicylic acid, oral contraceptives, dihydrofolate reductase inhibitors (eg, methotrexate, trimethoprim), sulfasalazine, hydantoins. 

Drugs that may be affected by HMG-CoA reductase inhibitors include oral contraceptives, diclofenac, digoxin, glyburide, phenytoin, and warfarin. Atorvastatin, lovastatin, and simvastatin are primarily metabolized by CYP3A4 they may interact with CYP3A4 inhibitors. 

Drug interactions with tizanidine hydrochloride include acetaminophen, alcohol, and oral contraceptives. 

Many drugs interact with folate to affect its absorption, antagonize its biochemical activity, or increase its loss from the body. These drugs include ethanol, phenytoin, and oral contraceptives. Salicylates can compete with foUc acid for plasma protein binding. Methotrexate, a cytotoxic agent, is a folate antagonist that inhibits the biosynthesis of this coenzyme. 

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