01Why does 5-alpha-reductase matter for a male fetus?
Propecia is a Type II 5-alpha-reductase inhibitor. That block lowers conversion of testosterone to DHT. DHT is necessary for normal development of male genitalia. In animal studies, finasteride caused abnormal development of external genitalia in male fetuses. Those outcomes resemble genetic 5-alpha-reductase deficiency in male infants. If the drug is used during pregnancy, the patient should be told about the potential hazard to a male fetus. The contraindication is women who are or may become pregnant. The indication is men only. Those two lines sit together on the same label. The tablet is Pregnancy Category X on that US prescribing information for Propecia.
02What if crushed dust touches skin?
Women who are pregnant or may become pregnant should not handle crushed or broken Propecia tablets because of possible absorption. If such a woman comes in contact with crushed or broken tablets, the contact area should be washed immediately with soap and water. That wash line is on the patient counseling pages. It is not a reason to keep using a crumbled tablet. Ask the pharmacy for a replacement of intact 1 mg tablets. Yogurt, a split, or a crushed 'half dose' is the same dust. Keep the film coat closed.
03Is finasteride in semen a labelled exposure?
Semen levels were measured in 35 men taking finasteride 1 mg a day for 6 weeks. In 21 of 35 samples, finasteride was undetectable (under 0.2 ng/mL). The mean level was 0.26 ng/mL. The highest level measured was 1.52 ng/mL. Using that highest level and assuming 100% absorption from a 5 mL ejaculate per day, estimated vaginal exposure was up to 7.6 ng per day. The label compares that figure to a 5 microgram dose that had no effect on circulating DHT in men.
04What if the tablet is still intact?
Propecia tablets are coated and will prevent contact with the active ingredient during normal handling, provided that the tablets have not been broken or crushed. A whole tablet in a closed bottle is the usual home picture. Do not split the 1 mg tablet to 'make it last.' The 1 mg dose ask keeps the swallow whole. A partner can fill a weekly box if every tablet stays intact. Crumbs in that box change the job to a dust problem.
05Was 1 mg studied as a hair drug in women?
In a 12-month study, 67 women received Propecia and 70 received placebo. Effectiveness could not be demonstrated. The indication remains men only. That study does not open the tablet for a woman who wants hair growth, and it does not cancel the crushed-tablet warning for someone who is or may be pregnant. Safety and effectiveness in pediatric patients have also not been established. The bottle is written for one adult man on the chart. A woman who wants hair growth is still outside the indication after that 12-month look.
06Should children handle the bottle?
Propecia is not indicated for pediatric patients. Safety and effectiveness in children have not been established. Keep the bottle where a child cannot chew a tablet. A broken tablet in a backpack is the same handling problem for a household member who is or may be pregnant. The written-order page assumes one adult man on the chart. Sharing a leftover 1 mg tablet is not a labelled use for the next person, child or adult. A chewed tablet in a backpack is also a crushed-tablet problem if a pregnant household member later handles the crumbs.