Ring and Patch
The transdermal contraceptive patch contains synthetic estrogen and progestin and remains effective for an entire week (Fig. 24.2). The patient should start the patch on the first day of her menstrual period and replace it weekly for 3 weeks. The fourth week is patch-free to allow a with-drawal bleed. Placement on clean, dry skin located on the buttocks, upper outer arm, or lower abdomen is recom-mended. Because of its ease of application and improved compliance, the “method failure” and “patient failure” of the patch are almost identical. Caution should be used when prescribing the patch for women weighing more than 90 kg (198 pounds) because of its decreased efficacy. Side effects and contraindications are similar to the OCs. A complaint specific to the patch, however, includes skin irritation from adhesive residue at the application site.
The contraceptive vaginal ring releases a sustained amount of synthetic estrogen and progestin daily (Fig. 24.3). Comparable with oral contraceptives in efficacy, the ring is associated with greater compliance because of its once-a-month usage. Placed into the vagina by the patient at the beginning of her menses, it is left in place for 3 weeks. Removal of the device results in a withdrawal bleed. The ring can be taken out of the vagina for up to 3 hours, if desired, without altering its efficacy. Because it is colorless and odorless, with a 2-inch diameter, most patients and their partners are unaware of the presence of the ring. An advantage of the ring over OCs is a decreased incidence of break-through bleeding.
Because the hormones in the vaginal ring and the transdermal patch do not get absorbed through the gastro-intestinal tract, some of the medication interactions that occur with combined oral contraceptives may not apply. However, metabolism still occurs in the liver and, there-fore, caution must be used.