Top 200 Prescription Drugs of 2003

Prescription drug sales in the United States grew substantially in 2003, supported by an upswing innew drug approvals and double-digit growth in many of the top-volume drug categories.

Sales grew by 11.5% to $217.4 billion in wholesale dollars—despite inroads by generic drugs in such categoriesas hypertension, diabetes treatment, and antidepressants—as leading brands lost patent protection. Genericusage reached a record level and claimed 43% of total scripts dispensed, according to IMS Health, the prescriptiondrug information company.

The year saw the approval of 21 new molecular entities (NMEs), compared with 2002, when only 17 NMEs cameto market. The 2002 number had been the lowest since 1983.

Merck/Schering-Plough's Zetia (ezetimibe) and AstraZeneca's Crestor (rosuvastatin calcium), available sinceSeptember, joined the group of lipid-lowering drugs, which remained thetop-selling class, with 10.9% wholesale-dollar growth. Zetia, a cholesterol-absorptioninhibitor, now ranks 148 in total retail and mail-order scripts dispensed (Tables 1 and 2).

Most patients using Zetia and Crestor were newly started on cholesterol-lowering therapy, according toIMS Health. Thus the impact of the new competition on Pfizer's Lipitor (atorvastatin calcium) and Merck'sZocor (simvastatin) was mitigated. Those 2 drugs maintained their leader status in the expanding category.

Eli Lilly and Company's new attention deficit/hyperactivity disorder(AD/HD) drug Strattera (atomoxetine hydrochloride) rapidly gained marketshare in AD/HD drugs and joined the rankings at 115 in wholesale sales to allchannels (including hospitals, longterm care facilities, and clinics).

New specialty drug entries included Genentech/Novartis' subcutaneousasthma drug Xolair (omalizumab) and Raptiva (efalizumab), a plaque psoriasisdrug by Genentech/Xoma. Also, Bayer's Levitra (vardenafil) and Lilly'sCialis (tadalafil) debuted to challenge Pfizer's Viagra (sildenafil citrate) in theerectile-dysfunction segment, each relying on heavy consumer marketing.Direct-to-consumer advertising overall played a larger role last year, helpingnew entries as well as established brands—such as Pfizer's Zyrtec (cetirizinehydrochloride), AstraZeneca's Nexium (esomeprazole magnesium),and Schering's Clarinex (desloratadine)—to grab market share.

Antihypertensive brands were thehardest hit by generics. Four angiotensin-converting enzyme inhibitors,Pfizer's Accupril (quinapril), Bristol-Myers Squibb's Monopril (fosinoprilsodium), and the brand versions of lisinopril—Merck's Prinivil and Zeneca'sZestril—lost patent and dropped in the script and dollar-sales rankings.

Along with the generic availability in the category, new mid-year guidelines bythe Joint National Committee on Prevention, Detection, Evaluation, andTreatment of High Blood Pressure, which favor diuretics in first-line treatment,impacted sales of antihypertensives.

Antihypertensive calcium channel blockers as a categorydeclined by 5% in dollar sales, according to IMS. Pfizer'sNorvasc (amlodipine besylate), however, remains a widelyused brand, ranking 4 in total scripts dispensed.

Generic vendors captured share in diabetes drugs with thepatent expirations of Bristol-Myers Squibb's Glucophage XR(metformin hydrochloride) and Pfizer's Glucotrol XL (glipizide).As those brands lost scripts and sales, metforminhydrochloride, offered by vendors including ParPharmaceutical and IVAX, and glipizide, with genericentries from Andrx and Watson Labs, moved up.

Strong contenders such as Pfizer's Zoloft (sertralinehydrochloride) and Forest Labs' Celexa (citalopram hydrobromide)contributed to an 11.9% increase in dollars in theantidepressant category, according to IMS Health.GlaxoSmithKline minimized loss of market share by convertingpatients from Paxil (paroxetine) to Paxil CR. Thereformulated molecule climbed to 72 in total scripts. Also inthe depression category, Organon's patent-losing drugRemeron (mirtazapine) lost position, as generic companiesincluding Akzo Nobel, Teva Pharmaceutical, Barr Labs,Mylan Labs, and Roxane lined up with low-cost alternatives.

As sales in the categories of heartburn and hay fever reliefwere challenged last year by generic and OTC availability,continuing strength of prescription brands in both segmentsis noteworthy. Boosted by the reported epidemic ofobesity and unhealthy eating habits, proton pumpinhibitors grew 12.9% in dollar sales. Tap Pharm's Prevacid(lansoprazole) and AstraZeneca's Nexium achieved doubledigitsales growth. Wyeth's Protonix (pantoprazole sodium)and Eisai/Janssen's Aciphex (rabeprazole sodium) placed inthe top 40 in dollar sales, despite inroads by omeprazole,supplied by 3 generic companies.

The switch of Schering's Claritin (loratadine) affected Rxantihistamines, which nose-dived by 28% in sales in 2003.Yet, leading brands, notably Pfizer's Zyrtec and Aventis'Allegra (fexofenadine hydrochloride), held up quite welldespite a full-year of OTC loratadine availability. Brands'efficacy often varies by patient, so drugs are less likely to bedeemed as interchangeable in the category.

Mr. Vaczek is a freelance medical writerbased in Yonkers, NY.