Despite price cutting measures taken by Merck to keep Zocor competitive, generic versions of Zocor (simvastatin) that became available during the last week of June have already captured 49% of new prescriptions in the US, according to data from healthcare information firm WoltersKluwerHealth. US patent protection for Zocor ended on June 23 allowing three new generic versions of simvastatin on the market.Teva Pharmaceutical’ s generic simvastatin captured 32% of the 236,000 new prescriptions for all versions of simvastatin during the last week of June. Dr. Reddy’s Laboratories, which makes generic simvastatin under an agreement with Merck, captured 14% of new prescriptions. The remaining 3% went to Ranbaxy Laboratories, which makes only the highest dose of simvastatin. Meanwhile, Pfizer’s Lipitor (atorvastatin calcium), the most popular statin drug and the world’s best selling prescription brand, saw its share of new prescriptions among all statin drugs fall to 40% during the last week of June, from 42% the week before, according to WoltersKluwer data reported in The Wall Street Journal. During the week ending July 7, Zocor and generic simvastatin accounted for 23% of cholesterol drugs prescribed for newly diagnosed patients or those switching medicines, compared with 20% for Lipitor. Just a month earlier, Lipitor claimed 23% of new prescriptions while Zocor accounted for just 16%.