Which drugs win the script popularity contest? Crestor, Synthroid and Nexium

It's Econ 101: The drugs that bring in the most money for their companies aren't necessarily the drugs used most by patients. After all, sales equals volume multiplied by price, and some generics are pennies per pill. Pricey drugs deliver more, sales-wise, even when smaller groups of patients use them.

So, let's take price out of the equation. If we could see inside every medicine chest in the United States, which pill bottles or delivery devices would we see most often?

Some numbers from the IMS Institute for Healthcare Informatics, reported by Medscape, tell us just that. The market research firm tallied the prescriptions written from October 2013 to September 2014--and while several are among the usual suspects, a few of the top-prescribed meds might surprise you. They aren't found in the top 10 when ranked by total sales.

First on the list is Crestor, the statin drug that's AstraZeneca's ($AZN) top seller. Prescriptions for the IMS timeframe topped 22.27 million. And that includes a bit of a slowdown, volume-wise, according to AstraZeneca's second-quarter report. Thanks to some price offsetting, Crestor brought in $2.8 billion in sales for the first half of 2014, about $1.5 billion of that in the U.S.

That Crestor is the most-prescribed drug is something of a good news, bad news story for the company. On the positive side, you can't argue with 22 million-plus scripts, especially in light of competition from Pfizer's ($PFE) now off-patent Lipitor. But AstraZeneca needs to ride this horse as fast as it can right now. Under a patent settlement, Crestor will face U.S. generic rivals in May 2016.

Second place? AbbVie's ($ABBV) treatment for hypothyroidism, Synthroid. It fell short of Crestor's script numbers by just 30,000 or so, with 22.26 million. Thanks to generics, however, it's nowhere in FiercePharma's ranking of top 10 drugs by 2013 sales. In fact, according to Medscape, it's No. 61, with $899 million.

We have another AstraZeneca med in third place. It's the stomach drug Nexium, which was prescribed 17.76 million times during the 12-month period. It's another entry here that's not among the top drugs by sales. For the first half of 2014, Nexium brought in $1.90 billion, down slightly from last year's $1.96 billion. Sales in the U.S. were down by 13% for the first half, to $939 million. Pfizer launched an over-the-counter version in March, under a deal with AstraZeneca, but generics haven't yet hit, thanks to quality-control problems at Ranbaxy Laboratories.

Fourth place goes to GlaxoSmithKline's ($GSK) asthma standby Ventolin HFA, with 17.74 million scripts. You probably know it by its generic name albuterol, thanks to the many copycat rivals that were on the market till new FDA regulations on CFC inhalers hit. Meanwhile, Advair Diskus, GlaxoSmithKline's newer respiratory med, stands in fifth place with 14.5 million scripts. It's another brand teetering on the edge of a big fall to generic rivals, with some copycats on the market in Europe, and others on their way in the U.S.

Rounding out the top 10 are Sanofi's ($SNY) diabetes drug Lantus, Shire's ($SHPG) newest ADHD drug Vyvanse, Pfizer's pain drug Lyrica, Boehringer Ingelheim's respiratory treatment Spiriva Handihaler, and Novartis' ($NVS) high blood pressure treatment Diovan. For 95 more drugs ranked by script numbers, check out Medscape's list.

- see the story from Medscape​ (reg. req.)

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