Are Yaz (drospirenone and ethinyl estradiol) and Slynd (drospirenone) the same in terms of dosage?

Yaz and Slynd Have Different Dosages of Drospirenone

No, Yaz and Slynd are not the same dose. Yaz contains 3 mg of drospirenone combined with 0.02 mg (20 mcg) of ethinyl estradiol, while Slynd contains 4 mg of drospirenone alone with no estrogen component 1, 2.

Key Differences Between Yaz and Slynd

Composition

• Yaz: Combined oral contraceptive (COC) containing:

  • Drospirenone 3 mg
  • Ethinyl estradiol 0.02 mg (20 mcg)
  • Packaged as 24 active tablets followed by 4 inert tablets (24/4 regimen) 1, 2

• Slynd: Progestin-only pill (POP) containing:

  • Drospirenone 4 mg
  • No estrogen component 3

Pharmacological Classification

Drospirenone is a fourth-generation progestin derived from 17α-spirolactone, not from testosterone like earlier generations of progestins 4. It has unique properties compared to other progestins:

• Antimineralocorticoid activity (similar to spironolactone)
• Antiandrogenic properties
• Structurally resembles natural progesterone 5

Clinical Implications of the Different Formulations

Contraceptive Efficacy

• Drospirenone 4 mg alone (Slynd) has a Pearl Index of 4.0 in the US and 0.93 in the EU
• Drospirenone 3 mg with ethinyl estradiol (Yaz) has a Pearl Index of 2.65 in the US and 0.44 in the EU 3

Blood Pressure Effects

• Drospirenone 3 mg with ethinyl estradiol (Yaz) may help mitigate the blood pressure-raising effects typically seen with other COCs due to drospirenone's antimineralocorticoid properties 4
• When administered as a progestin-only pill (Slynd), drospirenone 4 mg has been associated with decreases in systolic blood pressure of 8 mmHg and diastolic blood pressure of 5 mmHg in patients with baseline elevated blood pressure 4

Bleeding Profile

• Yaz (drospirenone/ethinyl estradiol) provides a more predictable bleeding pattern with regular withdrawal bleeding during the hormone-free interval
• Slynd (drospirenone alone) demonstrates higher rates of unscheduled bleeding and lower rates of scheduled bleeding 3

Important Considerations for Clinical Use

Venous Thromboembolism (VTE) Risk

• All COCs, including Yaz, increase the risk of VTE compared to non-users
• The baseline risk of VTE in non-pregnant, non-COC users is 1-5 per 10,000 woman-years
• Users of COCs have a VTE risk of 3-9 per 10,000 woman-years
• Users of drospirenone-containing COCs like Yaz have a VTE risk of about 10 per 10,000 woman-years 4
• Progestin-only pills like Slynd generally have a lower VTE risk than combined hormonal contraceptives

Hyperkalemia Risk

While there have been theoretical concerns about hyperkalemia with drospirenone due to its antimineralocorticoid effects:

• Multiple large retrospective cohort studies have found no increased risk of hyperkalemia with drospirenone-containing COCs compared to other COCs 4
• Even concomitant use of spironolactone and drospirenone has not been associated with significant increased risk for hyperkalemia 4

Therapeutic Applications

Yaz is FDA-approved for:

1. Contraception
2. Treatment of premenstrual dysphoric disorder (PMDD)
3. Treatment of moderate acne vulgaris in women at least 14 years old who desire contraception 6, 7

Slynd is approved for contraception and may be particularly beneficial for women who:

• Cannot use estrogen-containing contraceptives
• Have hypertension or risk factors for VTE
• Experience estrogen-related side effects with combined hormonal contraceptives

In conclusion, while both medications contain drospirenone, they differ significantly in dosage (3 mg vs 4 mg) and composition (combined with estrogen vs progestin-only), leading to different clinical profiles and applications.