AstraZeneca's gastrointestinal drug Nexium (esomeprazole) was the top-selling prescription drug in the US in the second quarter, displacing Sanofi's antiplatelet drug Plavix (clopidogrel) at the top of the pile.
Drugs.com, using figures from IMS Health, said Nexium sales came in at $1.38bn, just barely ahead of Otsuka's schizophrenia drug Abilify (aripiprazole), while Merck & Co's asthma treatment Singulair (montelukast) continued to gain ground rising one place to third with sales up 4 per cent to $1.29bn.
Overall, the data reveal a progressive decline in the dollar sales value of the top five products, which came in at a little under $6.3bn, down from $6.76bn in the first quarter and $7.04bn in the last quarter of 2011. For comparison, the top 5 drugs made more than $7.6bn in the second quarter of 2011.
GlaxoSmithKline's Advair Diskus (fluticasone and salmeterol) for asthma and chronic obstructive pulmonary disorder (COPD) gained two places to fourth, despite a dip in sales to $1.12bn, while AstraZeneca's Crestor (rosuvastatin) for elevated cholesterol nudged ahead to claim the fifth spot with sales of $1.12bn.
Plavix fell from first to ninth place in the rankings on the back of the loss of patent protection and generic competition, with sales declining more than 40 per cent to $686m.
Other brands on the slide including Pfizer's cholesterol drug Lipitor (atorvastatin), Takeda's Actos (pioglitazone) for diabetes and the immediate-release formulation of AstraZeneca's antipsychotic Seroquel (quetiapine.
Seroquel saw its sales cut in half to a little over $1bn and a drop of 95 places to bottom out the top 100 list, although the extended-release formulation Seroquel XR held up fairly well. The drug is patented in the US out to 2017 but still saw sales fall 5 per cent to $268m.
Interestingly sales of generic versions of Pfizer's Lipitor, which hit the US market late last year, also took a dive after posting the biggest gain in the first quarter, dropping five places to 14.
Looking at the big gainers, generic escitalopram - the active ingredient in Forest Laboratories' Lexapro brand of allergy treatment - saw sales double to $206m compared to the prior quarter, while other strong gainers included Abbott Laboratories' rheumatoid arthritis drug Humira (adalimumab) and Amgen's red cell stimulator Epogen (epoetin alfa).
• Full top 100 drugs by US sales list