Seasonique (ethinyl estradiol and levonorgestrel) is an oral hormonal contraceptive manufactured by Teva Pharmaceuticals. It is used to prevent pregnancy and also to slow down endometrial growth, and thereby ease inflammation and pain associated with endometriosis. The use of Seasonique results in fewer periods (around four) per year. Other brand names for the medication include LoSeasonique, Seasonal, Quartett, and Camrese.

The U.S. Food and Drug Administration (FDA) approved Seasonique following a clinical study (PSE-301), and The European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use has issued a positive opinion for its marketing authorization in the European Union.

How Seasonique works

There are two main hormones that play a crucial role in a woman’s menstrual cycle. Progesterone helps in stabilizing the endometrium after an embryo is implanted while estrogen is required for thickening the endometrium and development of the egg. Progesterone and estrogen counteract each other. In other words, when progesterone levels are high, estrogen levels are low, and vice-versa.

Seasonique is an extended-cycle oral contraceptive that consists of two tablets: levonorgestrel, a synthetic progestogen, and ethinyl estradiol, which is a semi-synthetic steroidal estrogen. This combination oral contraceptive suppresses ovulation (the process of releasing a mature egg from the ovaries). Seasonique is also known to induce changes in the cervical mucus and the uterine lining that makes it hard for sperm cells to reach the uterus. In the event of fertilization, this treatment can also prevent implantation of the fertilized egg to the uterine wall.

In endometriosis, tissue resembling the endometrium starts to grow outside the uterine cavity. These growths respond to a woman’s monthly hormonal cycles in the same way as the endometrium, but they have no safe route to exit the body, so cause inflammation and pain. Hormonal contraceptives can dampen the menstrual cycle and reduce the growth of endometrial lesions, and therefore offer some pain relief.

Seasonique in clinical trials

There have been several clinical studies to demonstrate the long-term safety and efficacy of Seasonique. A Phase 3 randomized multicenter study (PSE-301) evaluated its safety and efficacy in a 91-day extended regimen that spanned a period of about one year and included sexually active women of childbearing age. Seasonique received FDA approval and EMA authorization following the results of this study.

PSE-301 was followed up by a supportive Phase 3 randomized multicenter study (PSE-302), which included a similar 91-day extended regimen.

A Phase 3 open-label multicenter extension safety study (PSE-304; NCT00196352) evaluated the long-term safety of Seasonique up to an additional three years for those who had participated in PSE-301 and PSE-302. It was completed in 2006.

A prospective patient preference study found Seasonique to be similar for patient satisfaction and effectiveness in treating endometriosis-related pain when compared with Sharobel (norethindrone acetate), a progestin-only contraceptive.

A Phase 2 clinical trial (NCT00196313) to evaluate the efficacy of Seasonique for dysmenorrhea (painful periods) in patients up to 17 years of age was completed in 2008.


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