What is miglitol, and how does it work (mechanism of action)?
Miglitol is an oral medication used to control blood glucose (sugar) levels in
type 2 diabetes. It belongs to a class of drugs called alpha-glucosidase inhibitors which also includes acarbose (Precose). Carbohydrates that are eaten are digested by enzymes in the intestine into smaller sugars which are absorbed into the body and raise blood sugar levels. The process of carbohydrate digestion requires the pancreas to release into the intestine alpha-amylase enzymes which digest the large carbohydrates into smaller carbohydrates called oligosaccharides. The cells lining the small intestine then release alpha-glucosidase enzymes that further digest the oligosaccharides into
single sugars, like glucose, that can be absorbed. Miglitol is a man-made oligosaccharide designed to slow down the actions of alpha-amylase and alpha-glucosidase enzymes thereby slowing the appearance of sugar in the blood after a meal
(postprandial hyperglycemia). It does not increase insulin production, and its
effect on glucose is additive to the effect from other types of drugs used to
treat type 2 diabetes. Miglitol may reduce the weight gain that frequently is
caused by sulfonylureas, another type of drug used to treat type 2 diabetes. The FDA approved miglitol in December 1996.
What brand names are available for miglitol?
Glyset
Do I need a prescription for miglitol?
Yes
What are the side effects of miglitol?
The most common side effects of miglitol are:
- abdominal pain,
- diarrhea, and
- flatulence.
Rare but possible side effects include:
- low serum iron, and
- skin rash.
What is the dosage for miglitol?
- The initial miglitol dose may start at 25 mg three times daily and then increase after four to eight weeks to 50-100 mg three times daily.
- The maximum dose is 100 mg three times daily.
- Some patients may benefit from starting at 25 mg once daily to reduce the occurrence of upset stomach.
- Miglitol should be taken at the first bite of each meal.
- Smaller doses may be adequate for patients with severe kidney dysfunction.
- Miglitol therapy is not advised in the presence of certain medical conditions such as
inflammatory bowel disease (Crohn’s disease or
ulcerative colitis) or intestinal obstruction and chronic intestinal diseases involving difficulty with digestion or absorption such as Crohn’s disease. - Miglitol doses should be adjusted based upon blood glucose levels taken one hour after a meal and
blood HbA1c levels taken about three months after starting or changing the dose. (HbA1c is a chemical in the blood that is a good indicator of blood glucose control
over a prolonged period of time.)
Which drugs or supplements interact with miglitol?
Miglitol may interfere with
digoxin
(Lanoxin) absorption thereby decreasing digoxin blood levels and its effect. Therefore, the digoxin dose may need to be increased if miglitol is begun.
Miglitol also may reduce the effectiveness of ranitidine (Zantac) and propranolol (Inderal). An adjustment in dose based on monitoring of the patient may be necessary if miglitol is used with either of these drugs.
Intestinal adsorbents (for example, charcoal) and digestive enzymes (for example, amylase, pancreatin) may reduce the effect of miglitol and should not be taken concomitantly.
Adding a sulfonylurea during therapy with miglitol may lower blood glucose further, and the risk for developing hypoglycemia is greater. Caution should be used when combining these drugs.
If mild to moderate hypoglycemia occurs while taking miglitol in combination with a sulfonylurea, oral glucose (dextrose) should be used for treatment instead of sucrose (table sugar). Since miglitol blocks the digestion of sucrose to glucose, hypoglycemia will not be rapidly corrected if sucrose is given. Miglitol alone does not produce hypoglycemia.
Is miglitol safe to take if I’m pregnant or breastfeeding?
There are no safety and efficacy studies in humans.
Insulin therapy is recommended
during pregnancy.
Miglitol is excreted in human breast milk in small amounts. Drug exposure to the infant is expected although in small amounts. Miglitol is not recommended for nursing mothers.
What else should I know about miglitol?
What preparations of miglitol are available?
Tablets: 25, 50 and 100 mg.
How should I keep miglitol stored?
Miglitol should be stored at room temperature, 15 C to 30 C (59 F to 86 F), in an
air-tight container.