General

High Alert Medication: This medication bears a heightened risk of causing significant patient harm when it is used in error.

**Off Market Drug**
This medication is no longer available in the United States. Information provided here is for reference purposes only.

Pronunciation
a-seet-oh-HEX-a-mide

Trade Name(s)

• Dimelor [Canada]

• Dymelor

Pregnancy Category
Category C

Ther. class.
antidiabetics

Pharm. class.
sulfonylureas

Indications

Management of type 2 diabetes mellitus as an adjunct to diet

Action

• Lowers blood sugar by stimulating the release of insulin from the pancreas and increasing insulin sensitivity at receptor sites

• May also decrease hepatic glucose production

Therapeutic Effect(s):
Lowering of blood sugar in diabetic patients

Pharmacokinetics

Absorption: Well absorbed following oral administration

Distribution: Unknown

Protein Binding: 65–90% bound to plasma proteins

Metabolism and Excretion: Mostly metabolized by the liver; some conversion to hydroxyhexamide, which also lowers blood sugar

Half-life: Acetohexamide—1.3 hr (up to 30 hr in renal impairment); hydroxyhexamide—4.6–6 hr

TIME/ACTION PROFILE (hypoglycemic activity)

ROUTE	ONSET	PEAK	DURATION
PO	60 min	unknown	12–24 hr

Contraindication/Precautions

Contraindicated in:

• Hypersensitivity

• Known severe allergy to sulfonamides (e.g. sulfonylureas, thiazide/loop diuretics

• Type 1 diabetes mellitus

• Diabetic ketoacidosis

• OB: Lactation: Safety not established; insulin recommended during pregnancy

Use Cautiously in:

• Geri: Increased sensitivity; dosage reduction may be required

• Renal or hepatic impairment (increased risk of hypoglycemia)

• Infection, stress, or changes in diet (may alter blood sugar and requirements for glycemic control)

• Impaired thyroid, pituitary, or adrenal function (increased risk of hypoglycemia)

Adverse Reactions/Side Effects

CNS: dizziness, drowsiness, headache, weakness.

GI: anorexia, CHOLESTATIC JAUNDICE, constipation, cramps, diarrhea, drug-induced hepatitis, epigastric fullness, heartburn, increased appetite, nausea, vomiting.

Derm: photosensitivity, rash.

Endo: hypoglycemia, syndrome of inappropriate secretion of antidiuretic hormone (SIADH).

Hemat: APLASTIC ANEMIA, agranulocytosis, hemolytic anemia, leukopenia, pancytopenia, thrombocytopenia.

*CAPITALS indicates life-threatening.
*italic indicates most frequent.

Interactions

Drug-Drug

• Ingestion of alcohol may result in disulfiram-like reaction

• Effectiveness may be by concurrent use of calcium channel blockers, cholestyramine, corticosteroids, diazoxide, estrogens, phenytoin, isoniazid, hormonal contraceptives, loop diuretics, phenothiazines, rifampin, sympathomimetics, thiazide diuretics, thyroid hormones, and urinary alkalinizers

• beta blockers, chloramphenicol, fluconazole, gemfibrozil, histamine H2 receptor antagonists, methyldopa, MAO inhibitors, NSAIDS, probenecid, salicylates, sulfonamides, tricyclic antidepressants, and urinary acidifiers may the risk of hypoglycemia

• Concurrent use with warfarin may alter the response to both agents ( effects of both initially, then activity; close monitoring recommended during any changes in dosage)

Drug-Natural Products

• Glucosamine may worsen hypoglycemia

• Fenugreek, chromium, and coenzyme Q-10 may produce hypoglycemic effects

Route/Dosage

• PO (Adults): 250 mg once daily; dose can be increased as needed by 250–500 mg daily every 5–7 days (not to exceed 1.5 g/day; doses >1 g/day should be given as divided doses).
Geriatric patients or hepatic insufficiency—dosage reduction may be required;
renal dysfunction (CCr < 50 ml/min)—use not recommended (increased risk of hypoglycemia).

Availability

• Tablets: 250 mg, 500 mg

Assessment

• Observe patient for signs and symptoms of hypoglycemic reactions (sweating, hunger, weakness, dizziness, tremor, tachycardia, anxiety)

• Assess patient for allergy to sulfonamides

Lab Test Considerations

• Serum glucose and Hb A_1c should be monitored periodically throughout therapy to evaluate effectiveness of treatment

» Monitor CBC periodically throughout therapy. Notify physician or other health care professional promptly if decrease in blood counts occurs

» May cause an increase in AST, LDH, BUN, and serum creatinine

Toxicity and Overdose

• Overdose is manifested by symptoms of hypoglycemia. Mild hypoglycemia may be treated with administration of oral glucose. Severe hypoglycemia should be treated with IV D50W followed by continuous IV infusion of more dilute dextrose solution at a rate sufficient to keep serum glucose at approximately 100 mg/dl

Potential Nursing Diagnoses

• Imbalanced nutrition: more than body requirements (Indications)

• Noncompliance (Patient/Family Teaching)

Implementation

• High Alert: Accidental administration of oral hypoglycemic agents to non-diabetic adults and children has resulted in serious harm or death. Before administering, confirm that patient has diabetes. Do not confuse acetohexamide with acetazolamide

• Patients stabilized on a diabetic regimen who are exposed to stress, fever, trauma, infection, or surgery may require administration of insulin

» To convert from other oral hypoglycemic agents, the initial dose of acetohexamide should be about half the dose of tolbutamide and double the dose of chlorpropamide. A transition period is necessary with chlorpropamide because of the long half-life. Subsequent dose adjustments should be made based on the patient's response. For patients on an insulin dosage of <20 units/day, insulin can be discontinued immediately after starting acetohexamide. Patients taking >20 units/day should convert gradually by receiving an initial dose of acetohexamide of 250 mg and a 25–30% reduction in insulin dose the first day, with gradual insulin dosage reduction as tolerated. Hospitalization should be considered during the transition from insulin to acetohexamide

• PO: May be administered once in the morning or divided into 2 doses. Administer with meals to ensure best diabetic control and to minimize gastric irritation. Do not administer after last meal of the day

» Tablets may be crushed and taken with fluids if patient has difficulty swallowing

Patient/Family Teaching

• Instruct patient to take medication at same time each day. If a dose is missed, take as soon as remembered unless almost time for next dose. Patient should not take if unable to eat

• Explain to patient that this medication controls hyperglycemia but does not cure diabetes. Therapy is long-term

• Review signs of hypoglycemia and hyperglycemia with patient. If hypoglycemia occurs, advise patient to take a glass of orange juice or 2–3 tsp of sugar, honey, or corn syrup dissolved in water and to notify health care professional

• Encourage patient to follow prescribed diet, medication, and exercise regimen to prevent hypoglycemic or hyperglycemic episodes

• Instruct patient in proper testing of serum glucose and ketones. These tests should be closely monitored during periods of stress or illness and health care professional notified if significant changes occur

• May occasionally cause dizziness or drowsiness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known

• Caution patient to avoid alcohol while on acetohexamide as it may cause a disulfiram-like reaction (facial flushing, breathlessness)

• Insulin is the preferred method of controlling blood sugar during pregnancy. Counsel female patients to use a form of contraception other than hormonal contraceptives and to notify health care professional promptly if pregnancy is planned or suspected

• Caution patient to use sunscreen and protective clothing to prevent photosensitivity reactions

• Advise patient to inform health care professional of medication regimen before treatment or surgery

• Advise patient to carry a form of sugar (sugar packets, candy) and identification describing disease process and medication regimen at all times

• Advise patient to notify health care professional promptly if unusual weight gain, swelling of ankles, drowsiness, shortness of breath, muscle cramps, weakness, sore throat, rash, or unusual bleeding or bruising occurs

• Emphasize the importance of routine follow-up exams

Evaluation/Desired Outcomes

Control of blood glucose levels without the appearance of hypoglycemic or hyperglycemic episodes

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