Combination Therapy for High Cholesterol - Statins and Another Drug
Statins have been so successful that innovators can’t resist trying to make them more effective. Several pills are on the market that combine a statin drug with another non-statin compound with the idea that a one-two punch will really affect cardiovascular health.
There are medical and commercial reasons for doing this. With the expiration of patents the profit margins for statins has declined. The combination therapies can be patented, or otherwise protected under intellectual property laws, and thus generate economic profits for the makers.
Another benefit is that a combination drug could see higher compliance rates (patients actually taking them) than if the patient had to take more than one pill.
Simcor is a combination of simvastatin and niacin. The name Simcor is a trademark of Abbott Laboratories. Niacin is also Vitamin B3. This formulation is intended to be “extended-release”. The medicine enters the bloodstream over several hours. This is to avoid a flush from the niacin, although sometimes patients still experience a flush.
People taking blood thinners or vitamin supplements that include niacin need to be sure to mention this to their doctors. (Actually, your doctor should be advised of all drugs you take, including over-the-counter ones.)
Advicor combines niacin and lovastatin. It is therefore like Simcor, and also marketed by Abbott Laboratories. Abbott also sells Niaspan which is not a combination therapy, but is a controlled-release niacin pill.
In 2013 concerns about niacin-statin combinations were raised and doctors were quoted in the press as saying patients should not use the combination. A large clinical study resulted in large number of participants dropping out because of side effects. This may have been due to the include of laropiprant to reduce niacin flushing as earlier studies without laropiprant were not as negative.
Caduet is Pfizer’s entry to the combination therapy market. A combination of atorvastatin (which Pfizer sells under the name Lipitor) and amlodipine (Norvasc), this product contains both a statin and a calcium channel blocker high pressure drug. As these are often comorbid conditions (happen in the same person), the pill presents an easy go-to for the doctor, and perhaps increases usage in patienrs (fewer pills to take). As both these drugs are available as generics and will be more widely available as generics in the future (and the cost for generic atorvastatin is expected to fall), it is probably cheaper to get the two drugs separately as generics.
Vytorin is a combination of simvastatin and ezetimibe. Simvastatin is a statin (the most widely used one) and ezetimibe is a drug that inhibits the absorption of cholesterol through the digestive system Vytorin was approved by the FDA in 2004. The advertising stresses that Vytorin fights cholesterol levels two ways: both by reducing the amount of cholesterol produced in the body and by reducing the cholesterol that enters through the diet. Ezetimibe is sold as a separate drug (under the name Zetia), but the consensus recommended treatment for hypercholesterolemia is a statin. Some doctors prescribe ezetimibe for some of their patients, whether because those patients who cannot tolerate statins.or because they want a second-line of defense.. Vytorin is marketed in Europe under the name Inegy.)
An early study (2005) found Vytorin was more effective than atorvastatin at both reducing LDL levels and increasing HDL levels.
The drug company Merck makes Vytorin. Merck was the pioneer of simvastatin and makes Zetia. In 2005, soon after approval of Vytorin, Merck embarked on a large (18,000 patients) long-term study called IMPROVE-IT to see if there are safety concerns and/or efficacy improvements or detriments from this combination. The study passed a milestone in 2013 that allowed it to continue; this was a review by external experts who were allowed to view confidential information and it is considered good news. The IMPROVE-IT will continue until at least Sept 2014.
A 2008 study showed that the Vytorin was no better than simvastatin alone in preventing the build-up of plaque on blood vessels. Zetia lowers serum LDL but does not increase HDL or reduce inflammation the way statins do. The study raises the question of what kind of cholesterol control is useful. Vytorin does reduce LDL levels, but the question of whether it reduces mortality risk better than single-mode treatment is not clear, and that's what the IMPROVE-IT study is trying to establish.