Isotretinoin, marketed under the brand name Accutane, is widely used to treat acne. The Journal of Clinical Pharmacology notes that isotretinoin causes significant birth defects. If you have been treated for acne and subsequently wish to conceive, understanding how long does it takes your body to eliminate isotretinoin and its metabolites will help maximize your baby's safety.
Time Frame
Women vary widely in the speed with which their bodies eliminate isotretinoin. A 1998 study reported in the Journal of Clinical Pharmacology noted that of 11 women of childbearing age treated with isotretinoin for acne, half of the isotretinoin was eliminated at 29 hours. However, the standard deviation was 40 hours. This means that some women eliminated half the drug in more than 62 hours and other women eliminated half practically immediately.
Significance
The large variability of isotretinoin elimination times has significant consequences for women wishing to conceive. The specific elimination time or serum concentration for women does not correlate with clinical efficacy, ability to tolerate the drug, or the dose, according to the 1998 study, conducted by researchers in Toronto. Therefore, only an individual elimination test would reveal how much of the drug had been eliminated. If you wanted to conceive 48 hours after stopping isotretinoin treatment, you would not know if it was safe for the fetus.
Warning
Isotretinoin metabolizes into three different compounds, according to both RxList.com and Medscape. All are also harmful to a developing fetus. As with isotretinoin, the elimination rates of these compounds, or metabolites, varies. Without individual testing, it would be impossible to know if you eliminated them quickly or slowly. Thus, even if your body eliminates isotretinoin itself, conception still might not be safe. Eventually, however, the body eliminates them in urine and feces.
Misconceptions
Research on isotretinoin elimination rates has been variable. A report on children ages 12 to 15 years treated for acne showed much shorter elimination times and less variability than other studies. These pediatric studies reported that half the drug would be eliminated in 15 hours, with a range of between 10 to 20 hours. However, this difference is most likely due to differences in measurement times and research protocols and not due to differences in age of the participants. Thus, even teenagers may still have a significant concentration of isotretinoin 48 hours after stopping treatment and, if conceiving, could put the fetus at risk for significant birth defects.
Considerations
High-fat meals increase the absorption of isotretinoin. As reported on Rxlist.com, total plasma concentration of isotretinoin after a high-fat meal was more than double in adults who ate a high-fat meal compared to those who had not eaten anything. Even when more than double of the amount of drug was absorbed, the elimination rate of the drug from the body remained unchanged. Thus, high-fat foods increase the absorption of isotertinoin and may increase its effectiveness but it will not change the elimination rate. Therefore, if you want to conceive and are worried about how much isotretinoin is in your body, neither feeding nor fasting will help remove the drug from your body.
