Merck & Cohas reported a surge in third quarter net income, based on strong sales of key drugs, including Januvia, Janumet and Gardasil.

Diabetes medications Januvia and Janumet reported sales increases of 41% and 42% respectively over the corresponding 2010 results, amounting to sales figures of $846m and $350m.

Sales of Singulair, Merck’s leading asthma/allergic rhinitis treatment, rose 10% to $1.34bn, and it remains the company’s best-selling drug.

Company sales reached $12.02bn, representing an 8% increase, owing to a 5% boost from foreign exchange.