People with Type 2 diabetes who use metformin, sulfonylureas (such as glipizide, glyburide, and glimepiride), insulin, or a combination of these drugs can now add colesevelam (brand name Welchol) to their regimens if they need to further improve their diabetes control.
On January 18, the U.S. Food and Drug Administration (FDA) approved this new use for Welchol, which was originally approved in 2000 to help people reduce their LDL, or “bad,” cholesterol levels. In recent clinical trials, the drug has also been shown to help reduce improve blood glucose control in people with Type 2 diabetes. Now doctors can prescribe it as an add-on drug therapy for that purpose.
People with diabetes have an increased risk of cardiovascular disease (which can cause heart attack and stroke). This is why controlling both blood glucose levels and blood lipid levels (cholesterol and triglycerides) is so important for people who have diabetes. Welchol is now the only drug that is approved to lower LDL cholesterol levels and blood glucose levels.
The results of the most recent study of Welchol were presented at the 2007 American Diabetes Association’s Scientific Sessions. The study’s participants already took metformin, and some also took other blood-glucose–lowering drugs. For the study, some were assigned to add Welchol to the drugs they took, and some received a placebo.
After 26 weeks, the people who took Welchol plus metformin had an average reduction in their HbA1c levels (a measure of long-term blood glucose control) of 0.47% compared to those who took a placebo plus metformin. When the people who added Welchol to a combination of drugs were included in the analysis, the Welchol group reduced HbA1c levels by 0.54% compared to those who took a placebo. The participants who took Welchol—no matter what else they took—also ended up with significantly lower LDL cholesterol levels than the placebo group.
Other studies have found similar reductions in HbA1c levels when participants have added Welchol to sulfonylurea or insulin regimens.
As a cholesterol-lowering drug, Welchol can be used alone or in combination with statins. Welchol is a bile acid sequestrant, and it lowers cholesterol by a different mechanism than statin drugs use.
Welchol is usually taken in doses of three tablets, twice a day or six tablets, once a day. It should be taken with food and a liquid.
People who have bowel obstruction, triglyceride levels over 500 mg/dl, or a history of pancreatitis induced by high triglyceride levels should not use Welchol. People who have gastroparesis, gastrointestinal motility disorders, swallowing disorders such as dysphagia, or have had major gastrointestinal surgery should speak with their doctor about whether Welchol is appropriate for them.
As for potential side effects, Welchol has been shown to raise triglyceride levels, especially when combined with a sulfonylurea or insulin. The manufacturer recommends caution in prescribing the drug in people whose triglyceride levels are over 300 mg/dl. Welchol may also interfere with absorption of certain vitamins (A, D, E, and K) and drugs (glyburide [DiaBeta and others], levothyroxine [Synthroid and others], and oral contraceptives ethinyl estradiol and norethindrone). Therefore, it is recommended that people who take vitamin supplements or these drugs take them at least four hours before taking Welchol. They should also discuss other potential drug interactions with their doctor or pharmacist.
Other side effects that have been documented at low rates in trials of Welchol include constipation, stomach discomfort, nausea, colds and flu, hypoglycemia, and hypertension (high blood pressure).
Welchol is manufactured by Daiichi Sankyo, Inc.
