Slynd: second oral progestin-only contraceptive now available in Canada

Duchesnay is introducing a new oral progestin-only contraceptive, called Slynd. Slynd contains 24 drospirenone 4 mg (white) tablets, followed by four inert (green) tablets per blister card. The product is indicated for conception control in adolescent and adult women (≥ 12 years of age).1 Drospirenone, a progestin, lowers the risk of becoming pregnant primarily by suppressing ovulation.1 It is already marketed in Canada in combination with ethinyl estradiol for conception control or treatment of moderate acne (e.g., Mya, Yasmin, Yaz, Zamine), in combination with estetrol monohydrate (Nexstellis) for prevention of pregnancy, and in combination with estradiol-17β (Angeliq) for the management of vasomotor symptoms in postmenopausal women. Slynd is taken as one white (active) tablet daily for the first 24 days, starting on the first day of menses (Day 1 start), followed by one green (inert) tablet daily for the next four days. Tablets should be taken at about the same time each day.1 Read: Haloette: progestin/estrogen vaginal ring contraceptive now available The manufacturer notes that if one white active tablet is missed occasionally, ovulation suppression is maintained. If one white active tablet is missed, instruct the patient to take the missed tablet as soon as possible and continue with the daily regimen. Backup contraception is not required.1 If two or more white active tablets are missed, advise the patient to take the last missed tablet as soon as possible and continue the daily regimen until the pack is finished (one or more missed tablets will remain in the blister pack). Additional non-hormonal contraception (e.g., condom, spermicide) should be used as back-up if the patient has sex within seven days after missing two or more tablets.1 If one or more green inert tablets are missed, tell the patient to skip the missed pill days and continue taking one tablet a day until the pack is finished.1 If vomiting or diarrhea occurs within three to four hours after taking a tablet, advise taking another tablet (scheduled for the next day) as soon as possible. The new tablet should be taken within 12 hours of the usual time of tablet-taking, if possible.1 Read: QUIZ: Test your contraceptive care for youth IQ The most common adverse effects of Slynd are acne (3.8%), abnormal bleeding between regular menstrual periods (2.8%), headache (2.7%) and breast pain (2.2%). Unscheduled (breakthrough or intracyclic) bleeding and spotting are most common during the first three months of use. Bleeding irregularities may resolve over time or by changing to a different contraceptive product.1 Drospirenone is a spironolactone analogue with antimineralocorticoid activity. It has the potential to cause hyperkalemia comparable to a 25 mg dose of spironolactone. Slynd is contraindicated in women with conditions that predispose to hyperkalemia (e.g., renal impairment, hepatic impairment, adrenal insufficiency).1 Potential serious adverse effects include a possible slight increase in the risk of breast cancer. It is unknown whether drospirenone alone increases the risk of venous thromboembolism; if the risk is increased, it is expected to be lower than that of drospirenone-ethinyl estradiol combinations.1 Consider monitoring serum potassium concentrations in women at increased risk for hyperkalemia, such as those treated with a strong CYP3A4 inhibitor long-term. Serum potassium concentrations should be checked before starting treatment and during the first treatment cycle in women with chronic conditions who are receiving daily long-term treatment with medications that may increase serum potassium concentrations (e.g., angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, potassium-sparing diuretics such as spironolactone, potassium supplements).1 Co-administration with CYP3A4 inducers (e.g., rifampin) would be expected to decrease the systemic exposure of drospirenone, which could reduce contraceptive effectiveness or increase breakthrough bleeding.1 Medical Letter experts indicate that progestin-only oral contraceptives are similar in efficacy to combination oral contraceptives. They are primarily used by breastfeeding women and by women who cannot tolerate or have a contraindication to estrogen.2 Norethindrone 0.35 mg (Jencycla, Movisse) is the only other oral progestin-only contraceptive available in Canada. Head-to-head trials comparing drospirenone with norethindrone for prevention of pregnancy are not available, so their comparative efficacy and tolerability are unknown. Drospirenone has antimineralocorticoid activity and can cause hyperkalemia, while norethindrone does not.2 It is important to take norethindrone at the same time each day (within 3 hours) to prevent pregnancy; if a dose is taken more than three hours late, backup nonhormonal contraception is recommended for the next 48 hours. With drospirenone, however, backup nonhormonal contraception is not required unless two or more active tablet doses are missed.2 References 1. Duchesnay Inc. Slynd (drospirenone 4 mg tablets) product monograph. Blainville, QC; November 30, 2021. https://pdf.hres.ca/dpd_pm/00063783.PDF (accessed May 19, 2022). 2. Anon. Drospirenone (Slynd) — a new progestin-only oral contraceptive. Med Lett Drugs Ther 2020;62:18-19.

Slynd: second oral progestin-only contraceptive now available in Canada

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