A New Progestin-Only Contraceptive Pill

Andrew M. Kaunitz, MD


July 08, 2019

This transcript has been edited for clarity.

In May 2019, the US Food and Drug Administration approved the first new progestin-only pill (POP) in the past 45 years. This POP may be more effective than the currently available norethindrone formulation. The manufacturer has announced that the new POP will be marketed prior to the end of this year as Slynd. Each pack will include 24 tablets containing 4 mg of drospirenone and four inert tablets.

In the United States, use of POPs is largely limited to postpartum and lactating women, in whom fertility is low. The dose of the norethindrone POP is substantially lower than the amount of progestin in commonly prescribed combination norethindrone and norethindrone acetate oral contraceptives. Due to concerns regarding low contraceptive efficacy, some clinicians—myself among them—have been reluctant to use the norethindrone POP in fully fertile women, specifically those who are not postpartum or lactating.

What got my attention is that the dose of the new POP is relatively high, higher than the amount of drospirenone in combination oral contraceptives, raising the possibility that this new POP may be more effective than the current norethindrone POP.

Indeed, package labeling for the new POP describes the registration clinical trial which found a first-year failure rate of 4%, comparable to the failure rate observed in recent US clinical trials of estrogen-progestin pills and patches.

Progestin-only contraceptives are appropriate when the use of combination methods should be avoided due to elevated cardiovascular risks, including smokers age 35 and older and women with hypertension, migraines with aura, multiple cardiovascular risk factors, or a history of thrombosis.[1]

Unfavorable bleeding patterns are a common reason that women discontinue progestin-only contraceptives. Observations from the same clinical trial indicate that we should counsel women considering the new POP that unscheduled or random bleeding and spotting are common. Irregular bleeding is another common issue among women using the older norethindrone POP.

The drospirenone POP would appear to be a more effective method for women who should avoid combination hormonal contraceptives, and accordingly, will represent a welcome new choice for our patients.

Thank you for the honor of your time. I am Andrew Kaunitz

Dr Kaunitz reports no disclosures relevant to the contraceptive described in this video.

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