1. The drospirenone-only OC
The new POP with drospirenone 4 mg (Slynd), which received US Food and Drug Administration (FDA) approval in 2019, is packaged in a 24/4 formulation (24 hormonally active tablets followed by 4 inactive tablets). This formulation results in more predictable bleeding than does the 0.35-mg norethindrone POP, which contains 28 hormonally active tablets in each pack. In the US clinical trials of drospirenone 4 mg, scheduled bleeding decreased from 81% in cycle 1 to 20% in cycle 13. Unscheduled spotting and bleeding decreased from 61% to 40% in the same timeframe. Notably, this bleeding pattern was well tolerated; only 0.4% of trial participants discontinued this drospirenone POP due to problems with irregular bleeding or amenorrhea.
In contrast to the continuous norethindrone POP, which is not sufficiently dosed to consistently suppress ovulation, the 4-mg daily dose of drospirenone in this new POP is higher than the 3 mg used in commonly prescribed combination OCs that contain EE and drospirenone. This results in a POP that has more consistent ovulation suppression. Because this drospirenone POP is appropriately dosed and based on a longer-acting progestin, it is more forgiving of inconsistent pill taking. Accordingly, the missed-pill rules for this pill are the same as with combination estrogen-progestin OCs.1 The package labeling cites a first-year failure rate of 4%, but this includes unconfirmed pregnancies. The Pearl Index from the North American trials, based on confirmed pregnancies in nonbreastfeeding women, was 2.9.2
The package labeling for this drospirenone POP includes few contraindications. Conditions that preclude use include the US Medical Eligibility Criteria for contraception Category 4 condition (breast cancer in the last 5 years), renal impairment, and adrenal insufficiency. Other standard contraindications are listed in the prescribing information. Serum potassium levels should be checked (one time only) in the first cycle only for women who chronically use medications that could cause hyperkalemia, such as nonsteroidal anti-inflammatory drugs.
Given the ovulation suppression associated with this drospirenone POP, the safety of a progestin-only method, and the persistent popularity of OC pills, this pill should greatly increase the use of POPs beyond their traditional niche of postpartum and breastfeeding women. The advent of the drospirenone POP means that clinicians now have better options for women who have contraindications to estrogen and desire to control their own contraceptive use. It would be a logical consideration for over-the-counter accessibility.
2. Transdermal patch with ethinyl estradiol/levonorgestrel
The new EE/levonorgestrel transdermal contraceptive patch (Twirla) is soft and flexible, about the same size as other contraceptive patches, and contains EE 2.3 mg/levonorgestrel 2.6 mg. It provides total estrogen exposure that is similar to that of OCs with EE 30 µg and distinctly lower than estrogen levels seen with the original norelgestromin-containing patch or its 2 subsequent generic versions.3 This EE/levonorgestrel patch uses a new 5-layer drug delivery system that focuses the steroids for absorption beneath the patch; there is no peripheral spread of drug around the patch (FIGURE 1).
Transdermal patches offer the convenience of once-a-week dosing. One patch is used each week for 3 consecutive weeks followed by a patch-free week. Patches can be worn on the abdomen, buttock, or trunk (except breasts). Patches should not be placed consecutively on the same site; after a week’s rest, however, the first site can be reused. All transdermal contraceptive products are indicated for use only by women with a body mass index (BMI) <30 kg/m2.4
While no head-to-head trials have compared this new lower-dose patch with older patches, each patch was compared against a standardized pill, so meaningful comparisons can be made.
In each case, the circulating estrogen levels associated with use of the EE/levonorgestrel patch were considerably lower than those of the comparator pill, while the older norelgestromin patch consistently delivered higher total estrogen levels than its 35-µg comparator pill (TABLE).3 Along these lines, no VTE events occurred in women in the clinical trial of the new patch among women with a BMI <30 kg/m2.4
Women with a BMI <25 kg/m2 experienced lower Pearl Index (PI) pregnancy rates (3.5%) compared with women with a BMI between 25 and 30 kg/m2 (5.7%), according to clinical trial data cited in the package labeling. All the modern PI criteria were used to calculate these failure rates. Cycles in which no coitus occurred were excluded. Similarly, cycles in which another contraceptive method (for example, condoms) was added (even once) were excluded. Frequent pregnancy testing was done in the study centers and by the women at home. Bleeding patterns were well accepted; only 2.2% of study participants exited the study early due to menstrual disorders of any kind. Similarly, 3.1% of women discontinued use because of application site disorders. Women should be advised to press down on the patch edges after emerging from water exposure. Replacement patches are rapidly available from the manufacturer should permanent complete patch detachment occur.
Larger-scale phase 4 trials will be conducted to study the impact of this lower-dose patch on VTE rates.
Continue to: 3. A 1-year contraceptive vaginal ring...