Birth control firsts: Natazia

Birth control pills. Source: Ceridwen, Wikimedia Commons

On May 6, 2010, the FDA announced that it had approved Bayer’s Natazia (approved in Europe as Qlaira since May 2009) for use in women to prevent pregnancy with the exception that it should not be prescribed to women over 35 who smoke due to cardiovascular risks, and the company points out that its effectiveness has not been tested in obese (BMI >30) individuals. In two clinical trials that included more than 1800 women, the pill was deemed to be as effective as other oral contraceptives on the market.

This manifestation of the pill contains a synthetic estrogen called estradiol valerate and a progestin called dienogest - the first time this specific combination has been used. However, combining estrogen and progestin has been shown reduce the adverse hormonal effects of estrogen in regards to cancer risks and has become standard practice for long-term hormonal therapy, such as oral contraception. Most other birth control pills use the estrogen known as ethinyl estradiol.

 

The pill was approved to prevent pregnancy but was also shown to reduce bleeding in women with excessively heavy periods. However, obese women may not benefit from this drug. The lack of evidence in women with a BMI >30 is important because fat tissue produces estrogen, which can be counterproductive to the pill dose, as well as the fact that larger individuals absorb medication differently, which may alter the actual dose received in some individuals.

Natazia is expected to be available for prescription in summer 2010. According to Bayer, The pill should not be used by women with liver disease, who are pregnant, who have a high risk of thrombotic diseases, or who have undiagnosed hormone-sensitive reproductive cancers (which actually can’t be known until it is too late, so it is odd that the company mentions this except to stave off eventual lawsuits). Women should avoid smoking cigarettes while on the pill to prevent an increased risk of cardiovascular complications, especially women over 35 years of age. All birth control pills increase the risk of clotting and cardiovascular events to some extent, and Natazia is no different. The risk is highest during the first year of use.

However, some questions about the safety of the new birth control pill are being asked. Some feel that Bayer did not conduct appropriate safety testing, only efficacy for their marketing angle. And while the company is embroiled in lawsuits and recalls over Natazia’s predecessor, Yaz and Yasmin, some people wonder if they should not have been more diligent to assure both the FDA and the public that they can produce a safe contraceptive. (For more information on this see Jim Edwards’ May 7, 2010 article at bnet, “More questions than answers about safety of Natazia, Bayer’s new contraceptive”).

Because each individual reacts differently to hormones, having many options on the market broadens the access women have to hormonal birth control.

Before getting into the differences in the various types of oral contraceptives, it is important to understand how they work in general. Oral contraceptives contain hormones. The first pill in 1960 had high doses of hormones (estrogen and progestin), but this resulted in clotting and other dangerous side effects. Over the decades the hormone dose has been lowered and today’s combination oral contraceptives have the lowest effective doses. The hormones have been fine-tuned as more about the natural hormone rhythms in the human body have come to light and as synthetic estrogens have been produced. Fertility and pregnancy are hormonal conditions – by manipulating a woman’s hormone levels, ovulation and the steps leading to pregnancy can be controlled to the extent that pregnancy is prevented. Oral contraceptives are 92-99.7% effective at preventing pregnancy if used as directed for the particular pill.

One difference with Natazia is that it was shown in the clinical trials prior to approval to decrease menstrual bleeding. They found that for women with excessive or heavy menstrual bleeding, periods were lighter, and that 16% of women had amenorrhea (no period).

 

Another difference between Natazia and other birth control pills are the hormones they contain. Most birth control pills contain the estrogen ethinyl estradiol. Natazia is the first to contain the synthetic estrogen known as estradiol valerate, which is converted to estradiol within the body. In combination with this, Natazia contains the progestin dienogest, which other pills also contain, but this is the first approved four phase contraceptive. Usually birth control pills with ethinylestradiol/dienogest are monophasic – the woman receives one dose throughout the cycle, which prevents ovulation. The estradiolvalerate/dienogest combination in Natazia delivers four different doses through the 28-day cycle, offering a finer tuned control of the hormone levels. 

 

The specific four phase doses used in Natazia are 3 mg estradiol valerate for 2 days, 2 mg estradiol valerate and 2 mg dienogest for 5 days, 2 mg estradiol valerate and 3 mg dienogest for 17 days, and 1 mg estradiol valerate for 2 days, followed by two inert tablets like in other monthly contraceptives. The dienogest (progestin) dose is what is thought to prevent ovulation.

Common side effects of the pill in clinical studies included weight gain, acne, breast pain and discomfort, irregular menstruation, nausea/vomiting, and headache. The pill should not be used by women who are pregnant, have a high risk of thrombotic diseases, have undiagnosed hormone-sensitive reproductive cancers, or have liver disease. Associated cardiovascular and clotting risks are highest during the first year of use. In addition to the cardiovascular risks, the use of Natazia is associated with increased risks of gallbladder disease, hypertension, liver cancer, and ruptured cysts.

Despite these differences, Natazia was shown to be as effective as other birth control pills, and the side effects and complications for Natazia are not expected to be any different from the pills currently on the market. Women, especially those over the age of 35, should avoid smoking cigarettes while on the pill to prevent an increased risk of cardiovascular complications.