Short answer: The Proscar Patient Information says: if you forget to take Proscar, do not take an extra tablet. Just take the next tablet as usual. Proscar is one 5 mg finasteride tablet once a day, with or without food. The leaflet suggests taking it at the same time every day to avoid forgetting.
| Situation | What the label says |
|---|---|
| Schedule | One 5 mg tablet once a day, with or without meals (2) |
| Forgot a tablet | Do not take an extra tablet (Patient Information) |
| Next tablet | Take it as usual (Patient Information) |
| Half-life | About 6 hours, about 8 hours at age 70 and older (12.3) |
The prescribing information has no missed-dose section. The Patient Information, which is part of the same FDA label, says: if you forget to take Proscar, do not take an extra tablet. Just take the next tablet as usual.
The same leaflet says that to avoid forgetting, you can take Proscar at the same time every day.
Section 12.3 gives a mean plasma half-life of about 6 hours in younger men and about 8 hours in men 70 and older. The label says a trial of at least 6 months was generally needed to judge whether symptoms improve, so it is a long-term daily medicine.
Both are finasteride. Proscar is the 5 mg tablet for an enlarged prostate; Propecia is the 1 mg tablet for hair loss. Each has its own label and leaflet; see the Propecia page for what its label says.
This page summarizes FDA labeling. It is not personalized medical advice; confirm what to do with your prescriber or pharmacist.