Anticonceptivos orales de baja dosis


Los anticonceptivos orales de baja dosis aumentan el riesgo de problemas cardiovasculares, según informa “Journal of Clinical Endocrinology and Metabolism”.

  • Estudios anteriores habían sugerido una cierta relación entre anticonceptivos orales y enfermedad cardiovascular. Dichos estudios se hicieron sobre mujeres que tomaban anticonceptivos orales de baja dosis de primera y segunda generación y habían ofrecido resultados inconsistentes.
  • Ahora, investigadores de la Université de Sherbrooke, de Quebec (Canadá), llevaron a cabo un metaanálisis de 14 estudios con el objeto de establecer el riesgo cardiovascular asociado al uso de anticonceptivos orales combinados de baja dosis.
  • Los resultados obtenidos indicaban que los anticonceptivos orales de baja dosis se asociaban a el doble de probabilidades de problemas cardiovasculares (infarto de miocardio o ictus isquémico). El riesgo relativo de infarto de miocardio era de 1,84 y el de ictus isquémico de 2,12.
Tanto los anticonceptivos orales de baja dosis de segunda como de tercera generación se asociaron significativamente a incremento de riesgo de ictus isquémico. No obstante, la relación de anticonceptivos orales de tercera generación con infarto de miocardio no resultó significativa.

Link para bajar el articulo original PDF:

Journal of Clinical Endocrinology and Metabolism 2005; 90:3863-3870

Bibliografía:
  1. Centers for Disease Control and Prevention 1997 Vital and health statistics: fertility, family planning, and women’s health: new data from the 1995 national survey of family growth, Centers for Disease Control and Prevention/National Center for Health Statistics Ser 23, No. 19, 49–51
  2. United Nations 1999 World contraception use 1998.NewYork: United Nations
  3. Burkman RT, Collins JA, Shulman LP, Williams JK 2001 Current perspectives on oral contraceptive use. Am J Obstet Gynecol 185:S4–S12
  4. Kemmeren JM, Algra A, Grobbee DE 2001 Third generation oral contraceptives and risk of venous thrombosis: meta-analysis. BMJ 323:131–134
  5. Petitti DB, Sidney S, Bernstein A, Wolf S, Quesenberry C, Ziel HK 1996 Stroke in users of low-dose oral contraceptives. N Engl J Med 335:8–15
  6. Petitti DB 2003 Clinical practice. Combination estrogen-progestin oral contraceptives. N Engl J Med 349:1443–1450
  7. Nestler JE 1998 Polycystic ovary syndrome: a disorder for the generalist. Fertil Steril 70:811–812

FDA Panel, Bayer Birth Control Pills & Blood Clots


By Ed Silverman in Pharmalot

Nearly six months after a pair of studies found that women taking birth control pills containing a hormone called drospirenone are more likely to develop blood clots than those who take an older oral contraceptive, the FDA has decided to hold an advisory panel meeting in December to review the risks and benefits.

Meanwhile, the agency is continuing to review a separate agency-funded study that evaluated the risk of blood clots in users of several different hormonal birth control products (contraceptives). Preliminary results suggest an approximately 1.5-fold increase in the risk of blood clots for women who use drospirenone-containing birth control pills compared to users of other hormonal contraceptives.
And so, the agency will convene the Reproductive Health Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee to examine the risk of blood clots of drospirenone-containing birth control pills. The most widely known oral contraceptives containing this hormone are the Yaz and Yasmin pills sold by Bayer.
The scrutiny is not good news for Bayer. Nearly 7,000 lawsuits are pending in the US over alleged injuries and deaths relating to Yaz and Yasmin, as well as generics. The lawsuits allege Yaz and Yasmin have risks beyond those of traditional birth control pills and Bayer too aggressively promoted the pills without disclosing higher risks. Bayer was warned by the FDA in 2008 that TV ads were misleading and did not disclose added risks (see here) and recently was chastised in the UK for running a Yasmin ad that boasted the pill could prove beneficial on the same problems it may cause (read this).
As to the data, the FDA says it reviewed six published epidemiologic studies that evaluated the risk of blood clots in women using birth control pills containing drospirenone, but generated conflicting findings. Two were postmarketing studies required by the FDA or European regulators, and did not report any difference in clot risk between the pills and products containing levonorgestrel or other progestins. But two studies in 2009 reported a 1.5- to 2-fold higher risk in women who use pills containing drospirenone as opposed to contraceptives containing levonorgestrel.
More recently, two articles published in 2011 in the British Medical Journal reported a 2- to 3-fold greater risk of clots in women using oral contraceptives containing drospirenone rather than levonorgestrel. However, the FDA notes these were epidemiological studies and, so far, has not reached a conclusion on the risk for blood clots, but remains concerned about a potential increased risk (here is the FDA statement).