OBJECTIVES: Finasteride is indicated for the treatment of male pattern hair loss at 1mg strength and for male symptomatic benign prostatic hyperplasia (BPH) at 5mg strength. While the male pattern hair loss indication exclusivity does not expire until 2013, the BPH indication expired in 2006. Patients have been known to purchase generic finasteride in 5mg strength and split the pills into quarters as a less expensive alternative to the branded 1mg dose. The objective was to examine the uptake of generic finasteride in relation to the prescribing volume of branded finasteride for the treatment of male pattern hair loss to determine the impact of potential pill splitting on generic uptake and branded prescribing volume.   METHODS: Generic and branded finasteride were selected as case products. From 1992 to 2010 the volume of prescriptions (TRx) were collected monthly using SDI’s VONA databases and grouped according to branded and generic sales. RESULTS: Sales of generic finasteride significantly accelerated immediately after launch. The compound average growth rate (CAGR) of TRx of branded 5mg finasteride between 1992 and 2006 was 23.29%. Meanwhile, the CAGR of generic 5mg finasteride from 2006 to 2010 was 96.17%, signaling an aggressive growth trend. Interestingly, the sales of branded 1mg finasteride were not impacted as they maintained steady growth with a CAGR of 2.49% over the four years since generic launch. CONCLUSIONS: One hypothesis as to the immediate growth of generic finasteride after launch can be attributed to pill splitting; much of the volume increase was due to patients purchasing the much less expensive generic 5mg finasteride and quartering the pills. However, if pill splitting did occur, it did not appear to impact sales of branded 1mg finasteride as demonstrated by a maintained steady growth in TRx. This suggests that patients who pill split may not have been prior users of branded 1mg finasteride.