Those Cardizem Cd ads…

Healthfacts, Feb, 1993

Television watchers have recently been subjected to frequent prime time advertisements from Marion Merrell Dow, Inc. hawking its new prescription heart drug. The pitch is that people who are taking Cardizem should see their doctors about switching to Cardizem CD, a new version which can save them money.

The patent on the original Cardizem (generic name: diltiazem) has recently expired, and the generic versions are becoming available at a lower cost. Marion Merrell Dow, Inc. also makes a sustained-release version, Cardizem SR, which will lose its lucrative patent in the near future. The new Cardizem CD, which is prescribed primarily for hypertension, has a controlled release system that permits delivery of very high doses. (CD stands for controlled delivery.) This unique feature means that many people with hypertension or angina need take only one CD pill a day versus two or more of the older SR version.

The new one-a-day Cardizem CD has many advantages for the company. First, it may help increase drug-taking. People with hypertension are notorious for failing to take their medication. Second, it may be less expensive for consumers because fewer pills are required (a good selling point), but it is still highly profitable for Marion Merrell Dow, Inc. Finally, since Cardizem CD will be under patent protection for many years, its manufacturer can continue to be a major player in the very lucrative market for high blood pressure drugs.

RxNews spoke with a market analyst who estimated that 1992 first year sales for Cardizem CD will have reached $200 million, compared to $300 million each for Cardizem and Cardizem SR. Marion Merrell Dow, Inc. is betting that spending many millions on expensive T.V. and print ads for Cardizem CD will create "brand name loyalty" to help retain a good portion of the $600 million in Cardizem and Cardizem SR sales that might otherwise be lost to generic competition.

What about the claim that Cardizem CD is more economical? Normally, a new drug still under patent would be far costlier than generic competitors, but the one-a-day sustained release aspect does in fact make the new version cheaper. RxNews checked at a local pharmacy and found that Cardizem CD would be slightly less expensive than the generic version at doses of 180 mg or greater per day. The CD version is also somewhat cheaper for people who are taking more than 120 mg a day of Cardizem SR.

The best money-saving move for people taking Cardizem, however, would be a reconsideration of whether they should be taking the drug at all. Cardizem is a member of a drug class known as the calcium channel blockers. These drugs (other brand names include Procardia, Calan, Cardene, DynaCirc, and Isoptin) are known to be excessive in cost, heavily advertised to doctors, and unproven in effectiveness. They lower blood pressure, but, unlike the older antihypertensive drugs, they have not been shown in long-term clinical trials to reduce the rate of heart attack and stroke.

The National High Blood Pressure Education Program's latest report noted that the older antihypertensives, diuretics and beta-blockers, should be the treatment of first choice because their long-term efficacy has been proven. The calcium channel blockers, which can cost as much as 30 times more, should be prescribed as a last resort when other drugs fail to lower blood pressure (see HealthFacts, December 1992).

Instead of asking your doctor whether a switch to Cardizem CD would be OK, consumers who want cost effective treatment should inquire as to why they were prescribed a calcium channel blocker in the first place.

...And The Tavist Ads

The airwaves have also recently been crowded with advertisements for the over-the-counter antihistamine Tavist-1. Available as a prescription drug since 1977, the anti-histamine Tavist was recently approved by the FDA for OTC sales. The move to OTC from prescription involves proving to the FDA that lower doses of the drug (in this case 50% of prescription strength) are effective and safe.

The ads emphasize that because Tavist had previously been available only by prescription, it is a stronger, more effective medicine than other similar products. However, the Medical Letter, an independent, nonprofit publication that evaluates drugs, claims that Tavist is no more effective than some antihistamines long available OTC (22 January 1993). These drugs, Dimetane and Chlor-Trimeton, for example, are available at prices as low as one-eighth of the cost of Tavist-1.

Sandoz, the producer of Tavist, had a financial incentive to get into the OTC market so that its prescription version didn't have to compete with the less sedating Seldane, which now dominates the prescription antihistamine market.