‘Continuous low dose’?
Excerpt from Best Pills, Worst Pills April 2014 Newsletter:
NUVARING continues to be marketed as delivering a “continuous low dose,” suggesting greater safety relative to other hormonal contraceptives, but there is little evidence actually supporting this implication. Surprisingly, this first-of-its-kind product was tested in a small clinical trial involving only 16 human subjects to determine the blood levels of estrogen and progestin achieved with the product. Only data from this trial regarding average blood levels of estrogen and progestin, which were relatively low, appear on the current product label. However, the trial also demonstrated that there was significant variation in estrogen blood levels between subjects and over time for individual subjects. Most shocking of all: Four of the 16 subjects (25 percent) who participated in the small trial experienced an unexplained surge of estrogen, between two and four times the average levels, either at the start of their 30-day menstrual cycles or randomly in the middle of their cycles.
The drug’s original manufacturer, Organon, chose to cover up data from the two patients who experienced mid-cycle surges, neglecting to discuss the surges in a summary report for the trial the company submitted to the FDA in 1999, and omitted the data from the NUVARING professional label. The company explained that concentrations for certain patients were “considered to be … too high” to include in the analysis. The drug label did include data from the two women who experienced surges at the start of their cycles, but the figure that contained this information was compressed, making it difficult to see the surges clearly.
As of October 2013, the NUVARING label had not been updated to reveal the unexplained mid-cycle surges of estrogen. Unfortunately, correcting the label may do little to assist doctors in prescribing the product safely: Without conducting further large studies to provide better data on relative risk, it is difficult to know what impact these surges actually have on the chance of developing blood clots.
http://www.worstpills.org/recent_postings.cfm (Accessed 4/21/2014)