Despite widespread use of antidepressants – they were the most frequently dispensed prescription in 2011, according to IMS Health – these drugs are not the big moneymakers for pharmaceutical firms that they once were.
The demand for antidepressants remains significant. About 27 million Americans have taken antidepressants since 2005, according to a study published in the December 6, 2011 issue of the Annals of Internal Medicine. Up to one-third of Americans and 40 percent of Europeans could be classified as having a mental illness, according to a Thomson Reuters Pharma analysis released in March 2012. The World Health Organization forecasts that depression will displace heart disease as the heaviest disease burden by 2020.
The demand for, and use of, antidepressants does not, however, translate into higher sales figures. The Generic Pharmaceutical Association states that brand-name drugs often cost three times as much as their generic versions.
In the United States, spending on antidepressants fell from $11.7 billion in 2007 to $11 billion in 2011, according to IMS Health. While 80 percent of prescriptions written in 2011 were for generics, generics represented just 27 percent of spending.
The Thomson Reuters Pharma analysis found that global sales of antidepressants were $15 billion in 2003 but are expected to fall to less than $6 billion by 2016.
Generic Versions Overtake Branded Antidepressants
Many of the most popular antidepressants like Prozac, Zoloft, Lexapro, Paxil and Celexa have lost their patents and generic manufacturers have stepped in with their cheaper versions of the drugs.
When Eli Lilly's Prozac (fluoxetine) went off patent in 2001 and new drug products failed to make up for losses due to generic competition, the company's sales dropped 22 percent and $177 million in the first quarter of 2002. The company took a further drubbing, although temporary, as market values dropped from 74 cents a share to 58 cents a share. The fall was rapid for a drug which had reached $2.5 billion in sales in 2000 and represented one-quarter of Eli Lilly's business.
Pfizer's U.S. patent for Zoloft (sertraline) expired in 2006. In 2005, its last full year of market exclusivity, Zoloft sales reached $3.3 billion, reported CNN Money. Analysts predicted sales would dip to $470 million annually.
Lexapro (escitalopram), developed by Forest Laboratories in conjunction with Lundbeck, won two patent extensions. It lost its market exclusivity in on March 14, 2012.
GlaxoSmithKline's Paxil (paroxetine) has been off-patent since 2003.
Forest Labs' Celexa (citalopram) patent expired in 2003.
Introduced by Wyeth in 1993 and now marketed by Pfizer, Effexor (venlafaxine) went off-patent in the United States and Canada in 2006.
Eli Lilly's Cymbalta (duloxetine) was approved by the FDA for depression and diabetic neuropathy in 2004. It is scheduled to lose its patent in 2013.
Wellbutrin (bupropion), developed by Burroughs Wellcome, later acquired by GlaxoSmithKline, lost its patent in 2006. During its last full year of exclusivity, Wellbutrin XL sales exceeded $1.3 million.
A Consumer Reports (CR) analysis of antidepressant drugs found that all-antidepressants were about equal in their success in relieving depression. The CR report suggested choices could come down to safety, effectiveness, cost, side effects and the presence of other medical conditions that could affect the drug's safety and effectiveness.
CR Best Buy picks were generic drugs with a long safety track record including bupropion, citalopram, fluoxetine, paroxetine and sertraline.
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