NR 566 Final Exam Guide

How to respond to missed doses or changing of contraceptive types from one to another? - For products that use a 28-day cycle, the following recommendations from the Centers for Disease Control apply: • If one or more pills are missed in the first week, take one pill as soon as possible and then continue with the pack. Use an additional form of contraception for 7 days. • If one or two pills are missed during the second or third week, take one pill as soon as possible and then continue with the active pills in the pack but skip the placebo pills and go straight to a new pack once all the active pills have been taken. • If three or more pills are missed during the second or third week, follow the same instructions given for missing one or two pills but use an additional form of contraception for 7 days. For combination OCs that use an extended or continuous cycle, up to 7 days can be missed? - with little or no increased risk for pregnancy provided that the pills had been taken continuously for the prior 3 weeks. If one or more doses is missed or taken greater than 3 hours after the scheduled dose, the following guidelines apply: - -If one pill is missed, it should be taken as soon as remembered and backup contraception should be used for at least 2 days. The pills should be resumed as scheduled on the next day. -If two pills are missed, the regimen should be restarted and backup contraception should be used for at least 2 days. -If two or more pills are missed and no menstrual bleeding occurs, a pregnancy test should be done. Types of contraceptives and which would be best for specific patient scenarios - Combination OCs should be avoided by women with certain cardiovascular disorders (see later) as well as by women older than 35 years who smoke. For women in these categories, an alternative method (e.g., diaphragm, progestin-only pill, or IUD) is preferable.For women who engage in coitus frequently, OCs or a long-term method (e.g., Nexplanon, Depo-Provera, IUD) are reasonable choices. when sexual activity is limited, and if individual has multiple partners use of a spermicide, condom, or diaphragm may be more appropriate. Because barrier methods combined with spermicides can offer some protection against STDs (as well as providing contraception) If adherence is a problem (as it can be with OCs, condoms, and diaphragms), usterm-16e of a long-term method (e.g., vaginal contraceptive ring, IUD, Nexplanon, Depo-Provera) can confer more reliable protection. What effect does CYP450 inhibitors or inducers have on OCs? o Recall examples of CYP450 inhibitors and inducers from NR565 (Chapter 4 in textbook) o How does this impact prescribing of OCs? - Inhibitors: Inducers: Acyclovir Carbamazepine Ciprofloxacin Phenobarbital Ethinyl estradiol Phenytoin Fluvoxamine Primidone Isoniazid Rifampin Norfloxacin Ritonavir Oral contraceptives Tobacco Zafirlukast St. John's wort Zileuton As a rule, high-estrogen OCs are reserved for women taking drugs that induce P450. drugs that interact with oral contraceptives? - Products that induce hepatic cytochrome P3A4 can accelerate OC metabolism and thereby reduce OC effects. indications are reduced OC blood levels, such as breakthrough bleeding or spotting. If these signs appear, it may be necessary to either (1) increase the estrogen dosage of the OC, (2) combine the OC with a second form of birth control (e.g., condom), or (3) switch to an alternative form of birth control. can decrease the benefits of warfarin and hypoglycemic agents. May require increased dosage OCs can impair the hepatic metabolism of several agents, including theophylline, tricyclic antidepressants, diazepam, and chlordiazepoxide. Can cause toxicity. if Toxicity occurs dosage may have to be reduced.