Diabetes Medicine: Bile Acid Sequestrants and Dopamine Receptor Agonists

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Diabetes Medicine: Bile Acid Sequestrants and Dopamine Receptor Agonists

Well, we just about covered all of the diabetes pills available in the U.S. It was no small feat!

If your head is swimming after reading about all of these different medicines, that’s to be expected. Diabetes management is complex, for sure. No two people’s diabetes is alike, and while treatment goals may be very similar, the path to reaching those goals often takes many twists and turns. We’re fortunate that there are so many treatment options available. The choice of treatment isn’t always clear-cut: Most guidelines recommend starting off with metformin; this much is clear. If or when metformin alone doesn’t cut it, providers and patients alike need to consider and discuss the various options. In general, once a person’s HbA1c level goes above 8.5%, it’s unlikely that diabetes pills alone will be enough to lower blood sugar levels to target range. At this point injectable medicines, such as GLP-1 agonists and insulin, should be considered.

This week, we’ll wrap up the diabetes pills series with a focus on two lesser-known (and lesser-used) pills: bile acid sequestrants and dopamine receptor agonists.

Bile acid sequestrants

Bile acid sequestrants are a type of medicine that is mostly used to lower LDL (“bad”) cholesterol. As the name suggests, these medicines bind to bile acids in the intestines and prevent them from being absorbed back into the blood. The liver then makes more bile; cholesterol is used to make bile, so more cholesterol is used by the liver, thus reducing the amount of cholesterol in the blood. While statins are more commonly used these days to help lower cholesterol, not everyone can take them, so bile acid sequestrants are another option.

One of the drugs in this class is called colesevelam (brand name Welchol). Not only does it lower LDL cholesterol, it lowers blood sugar, too, when taken along with metformin, sulfonylureas or insulin. It’s not typically given as monotherapy (on its own) to lower blood sugars. Colesevelam was approved by the FDA in 2008 to be used as antihyperglycemic agent.

Colesevelam works in the intestines, therefore, to help manage blood sugars. Interestingly, it’s not known how this drug helps to lower blood sugars. But when taken with other glucose-lowering drugs, colesevelam may lower A1C levels by 0.5%.

How it’s taken

Colesevelam is taken as either three tablets twice a day or six tablets once a day with food and liquids.

Side effects

Colesevelam, ironically, may raise triglyceride (blood fat) levels, and may cause constipation, stomach upset, low blood sugar and high blood pressure.

Facts to know

Colesevelam can interfere with the absorption of other medicines (including diabetes pills) and vitamins; other medicines should be taken four hours apart from colesevelam.

It can increase blood levels of metformin when taking metformin ER (extended-release).

It shouldn’t be taken by anyone who has high triglyceride levels or a history of intestinal blockage.

Dopamine receptor agonists

Dopamine receptor agonists are drugs that act on the dopamine receptors in the brain, helping to replace dopamine when the brain can no longer make it. These drugs are used to treat Parkinson’s disease, ADHD, pituitary tumors and restless legs syndrome. Although it is not understood exactly how this medicine lowers blood sugar levels, it appears to do so by working primarily in the brain. Bromocriptine (Cycloset) was approved by the FDA in 2009 for type 2 diabetes. This drug can be used alone, along with diet and exercise, or with other types of diabetes pills. It’s best used in people with type 2 diabetes who still produce enough insulin and who have only mildly high blood sugar levels.

How it’s taken

Bromocriptine is taken within two hours of waking with food.

Side effects

Side effects include drowsiness, nausea, vomiting, headache, fatigue and dizziness.

Facts to know

Bromocriptine may not be appropriate for you if you take other medicines for certain mental health conditions, migraines, Parkinson’s or restless legs syndrome.

Taking this drug could exacerbate (worsen) certain types of psychotic disorders. It can also interfere with some drugs used to treat psychotic disorders.

If you take bromocriptine, tell your doctor if you have dizziness, nausea, or episodes of fainting.

These two drugs are not commonly used to treat diabetes, but they’re options. If you’re not at your target A1C and/or blood sugar range, it’s time to have a discussion with your doctor about options that are best for you, based on your A1C, other medical conditions and medications that you take, possible side effects and cost.

Want to learn more about the role of medicines in treating diabetes? Read the rest of diabetes educator Amy Campbell’s eight-part series on diabetes drugs, covering metformin, sulfonylureasmeglitinidesthiazolidinedionesDPP-4 inhibitorsSGLT2 inhibitorsalpha-glucosidase inhibitorsnon-insulin injectable diabetes medications, and insulin.

Originally Published September 8, 2015

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