Acarbose

BRAND NAMES

Precose® – It is in the dosage form of acarbose, available in 25 mg, 50 mg, and 100 mg tablets. It is administered orally with the first bite of each main meal, typically 50 mg three times daily, with dose adjustments based on glycemic response and tolerance.

Glucobay® – In Glucobay®, acarbose is the main active ingredient used in adults with type 2 diabetes to control postprandial blood glucose levels.

MECHANISM OF ACTION

Acarbose inhibits enzymes in the small intestine called alpha-glucosidases, which are responsible for breaking down complex carbohydrates into simple sugars like glucose. By slowing the enzymatic hydrolysis of starches and disaccharides, acarbose delays glucose absorption after meals. This leads to a reduction in postprandial blood glucose levels. Unlike insulin or sulfonylureas, acarbose does not directly stimulate insulin secretion, but it helps improve overall glycemic control by modulating carbohydrate absorption and reducing glucose spikes following meals.

PHARMACOKINETICS

Absorption

Acarbose acts locally in the gut with minimal systemic absorption. It must be taken with meals to slow carbohydrate digestion and reduce postprandial glucose spikes. Its effect depends on meal composition and timing, as the drug works only when present with ingested carbohydrates.

Distribution

Acarbose has minimal systemic absorption, so its apparent volume of distribution is very low, with its effects largely confined to the gastrointestinal tract.

Metabolism

 Acarbose is minimally absorbed and primarily metabolized in the gastrointestinal tract by intestinal bacteria and digestive enzymes. It undergoes hydrolysis to inactive metabolites, and only a very small fraction reaches systemic circulation. Most of the drug is excreted unchanged in the feces, with negligible pharmacologically active metabolites in the plasma.

Excretion

Following oral administration, the majority of acarbose is excreted unchanged in the feces, with only a small fraction metabolized by intestinal bacteria. Very little of the drug is absorbed systemically, so urinary excretion is negligible.

PHARMACODYNAMICS

Acarbose inhibits intestinal alpha-glucosidases, slowing the breakdown of complex carbohydrates into glucose. This reduces postprandial blood glucose spikes without directly affecting insulin secretion. The pharmacological effect can be monitored by measuring post-meal plasma glucose levels.

DOSAGE AND ADMINISTRATION

Acarbose is available in tablet form, typically in strengths of 25 mg, 50 mg, and 100 mg. It should be taken orally with the first bite of each main meal, as its effect depends on the presence of carbohydrates in the gut. The usual starting dose is 50 mg three times daily, which may be gradually increased based on tolerance and glycemic response. Take acarbose at roughly the same times each day with meals for optimal postprandial glucose control.

CONTRAINDICATIONS

Acarbose is contraindicated in patients with chronic intestinal diseases (such as inflammatory bowel disease, colonic ulceration, partial intestinal obstruction) that may worsen with increased intestinal gas or motility. It should also not be used in patients with hypersensitivity to acarbose. Caution is advised in patients with liver disease, as rare cases of hepatotoxicity have been reported, and liver function monitoring is recommended during long-term therapy.

DRUG INTERACTIONS

Acarbose can have interactions with other medications that affect blood sugar, which may necessitate close monitoring. Because of the risk of hypoglycemia when combined with other antidiabetic drugs, individuals taking insulin or sulfonylureas should be carefully monitored, and dosage adjustments may be required.

FOOD INTERACTIONS

Acarbose should be taken with the first bite of a meal to be effective. Its blood sugar–lowering effect depends on food intake, so it must not be taken on an empty stomach. There are no known interactions with specific foods, but patients should be aware that consuming alcohol may increase the risk of low blood sugar when used with other antidiabetic medications.

SIDE EFFECTS

• Flatulence (excess gas) 

• Abdominal discomfort, bloating, or cramping 

• Diarrhea or loose stools 

• Nausea 

• Rarely, skin rash or itching 

• In children: mild abdominal pain, bloating, or increased gas 

TOXICITY

Acarbose’s most significant adverse effects are gastrointestinal, including severe abdominal pain, bloating, and diarrhea. Rarely, it can cause elevated liver enzymes or hepatotoxicity, particularly with long-term use. Severe hypoglycemia may occur if acarbose is taken with other antidiabetic medications.