Is Triquilar (ethinyl estradiol and levonorgestrel) a progesterone-only pill or a combination pill?

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Triquilar is a Combination Pill, Not a Progesterone-Only Pill

Triquilar (ethinyl estradiol and levonorgestrel) is a combination oral contraceptive pill containing both estrogen and progestin components, not a progesterone-only pill. 1, 2

Composition and Classification

  • Triquilar is a triphasic combined oral contraceptive containing varying doses of ethinyl estradiol (estrogen) and levonorgestrel (progestin) throughout the cycle 2
  • The specific formulation includes:
    • First 6 days: 30 micrograms ethinyl estradiol + 50 micrograms levonorgestrel
    • Next 5 days: 40 micrograms ethinyl estradiol + 75 micrograms levonorgestrel
    • Last 10 days: 30 micrograms ethinyl estradiol + 125 micrograms levonorgestrel 2, 3

Distinguishing Between Combination and Progestin-Only Pills

  • Combined oral contraceptives (COCs) like Triquilar contain both estrogen and progestin components 4
  • Progestin-only pills (also known as "mini-pills") contain only progestin and work primarily by thickening cervical mucus, not primarily by inhibiting ovulation 4
  • Combined pills like Triquilar work by inhibiting gonadotropin-releasing hormone, follicle stimulating hormone, and luteinizing hormone, preventing ovulation 4

Clinical Implications of Combination vs. Progestin-Only Pills

  • Combined pills like Triquilar carry different risk profiles than progestin-only pills, particularly regarding thrombotic risk 4
  • Patients with certain conditions (such as positive antiphospholipid antibodies, history of thrombosis, or certain autoimmune conditions) should avoid combined pills like Triquilar 4
  • The risk of venous thromboembolism is higher with combined pills like Triquilar compared to progestin-only methods 4

Pharmacokinetic Properties

  • During treatment with Triquilar, levonorgestrel levels in serum accumulate by approximately four times compared to single-dose administration 5
  • The triphasic design of Triquilar was developed to provide contraceptive efficacy while reducing the total dose of progestin compared to monophasic formulations 3
  • Triquilar affects hormone binding proteins, with studies showing increases in sex hormone-binding globulin (SHBG) concentrations by approximately two-fold during treatment 5

Common Pitfalls in Prescribing

  • Mistaking triphasic combined pills like Triquilar for progestin-only pills could lead to inappropriate prescribing for patients with contraindications to estrogen 4
  • Patients with certain conditions (cyanosis, Fontan physiology, mechanical valves, prior thrombotic events, pulmonary arterial hypertension) should avoid estrogen-containing contraceptives like Triquilar 4
  • Progestin-only methods are generally considered safer options for patients with contraindications to estrogen 4

References

4
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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