Chlorpropamide

Pronunciation: klor-PRO-puh-mide
Class: Sulfonylurea

Trade Names

Chlorpropamide
- Tablets 100 mg
- Tablets 250 mg

APO-Chlorpropamide (Canada)

Pharmacology

Decreases blood glucose by stimulating insulin release from pancreas.

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Pharmacokinetics

Absorption

Rapidly absorbed. T max is 2 to 4 h. C max is 30 mcg/mL.

Distribution

Excreted in breast milk.

Metabolism

Metabolized in the liver.

Elimination

The t ½ is about 36 h. 80% to 90% is excreted in urine within 96 h (as unchanged drug and as hydroxylated or hydrolyzed metabolites).

Onset

Within 1 h.

Peak

3 to 5 h.

Duration

24 to 60 h.

Special Populations

Renal Function Impairment

The t ½ is prolonged. Dosage adjustment may be needed.

Indications and Usage

Adjunct to diet to lower blood glucose in patients with non–insulin-dependent diabetes mellitus (type 2) whose hyperglycemia cannot be controlled by diet alone.

Unlabeled Uses

Control of neurogenic diabetes insipidus.

Contraindications

Hypersensitivity to sulfonylureas; diabetes complicated by ketoacidosis with or without coma; sole therapy for insulin-independent (type 1) diabetes mellitus; diabetes when complicated by pregnancy.

Dosage and Administration

Adults Initial dose

PO 250 mg/day in single dose.

Elderly Initial dose

PO 100 to 125 mg/day in single dose.

Maintenance

PO 100 to 250 mg/day in single dose.

Severely Diabetic Adults

PO up to 500 mg/day; avoid doses above 750 mg/day.

Storage/Stability

Store in cool environment in tightly closed container.

Drug Interactions

Androgens, anticoagulants, chloramphenicol, clofibrate, fenfluramine, methyldopa, MAOIs, phenylbutazone, probenecid, salicylates, sulfonamides, tricyclic antidepressants, urinary acidifiers

May increase hypoglycemic effect.

Beta-blockers, corticosteroids, diazoxide, hydantoins, rifampin, thiazide diuretics, urinary alkalinizers

May decrease hypoglycemic effect.

Laboratory Test Interactions

LFTs

Drug causes elevated results.

BUN and creatinine

Drug causes mild to moderate elevations.

Adverse Reactions

Cardiovascular

Increased risk of CV mortality when compared with patients treated with diet alone.

CNS

Dizziness; vertigo.

Dermatologic

Allergic skin reactions; eczema; pruritus; erythema; urticaria; morbilliform or maculopapular eruptions; lichenoid reactions; photosensitivity.

EENT

Tinnitus.

GI

GI disturbances (eg, nausea, epigastric fullness, heartburn).

Hematologic

Leukopenia; thrombocytopenia; aplastic anemia; agranulocytosis; hemolytic anemia; pancytopenia; hepatic porphyria.

Hepatic

Cholestatic jaundice; elevated LFTs.

Metabolic

Hypoglycemia; SIADH with water retention and dilutional hyponatremia, especially in patients with CHF or hepatic cirrhosis.

Miscellaneous

Disulfiram-like reaction; weakness; paresthesia; fatigue; malaise.

Precautions

Monitor

Blood sugar

Check blood sugar levels frequently and observe for symptoms of hypoglycemia or hyperglycemia and report to health care provider.


Pregnancy

Category C . Insulin is recommended to maintain blood glucose levels during pregnancy. Prolonged severe neonatal hypoglycemia can occur if sulfonylureas are administered at time of delivery. If administering to pregnant patient, discontinue 2 days to 4 wk before expected date of delivery.

Lactation

Excreted in breast milk.

Children

Safety and efficacy not established.

Elderly

Particularly susceptible to hypoglycemic action. Hypoglycemia can be difficult to recognize in elderly patients.

Renal Function

Use drug with caution and monitor renal function frequently.

Hepatic Function

Use drug with caution and monitor liver function frequently.

Debilitated patients

Particularly susceptible to hypoglycemic action.

Disulfiram-like syndrome

A sulfonylurea-induced facial flushing reaction may occur when administered with alcohol.

Switch to hypoglycemic agent

When discontinuing chlorpropamide and switching to another oral hypoglycemic agent, exercise caution for 2 wk; prolonged action of chlorpropamide may provoke hypoglycemia.

Overdosage

Symptoms

Hypoglycemia, tingling of lips and tongue, hunger, nausea, lethargy, confusion, agitation, nervousness, tachycardia, sweating, tremor, convulsions, stupor, coma.

Patient Information

  • Explain that this medication will not cure disease.
  • Emphasize that drug must be taken on daily basis and should not be discontinued abruptly.
  • Tell patient that drug may cause GI upset and to take it with food if GI upset occurs.
  • Teach patient to self-monitor blood glucose.
  • Inform patient to contact health care provider if symptoms of hypoglycemia occur (eg, fatigue, excessive hunger, profuse sweating, numbness of extremities).
  • Instruct patient to notify health care provider if symptoms of hyperglycemia occur (eg, excessive thirst or urination, urinary glucose, or ketones).
  • Tell patient to report constipation, nausea, vomiting, drowsiness, dizziness, fever, sore throat, rash, or unusual bruising or bleeding to health care provider.
  • Inform patient that this drug is not a substitute for exercise and diet control; patient must follow prescribed regimens of diet, exercise, and personal hygiene.
  • Instruct patient to inform all health care providers involved in patient's care that this drug is being taken.
  • Advise patient not to take any medication (including otc) or drink alcoholic beverages without consulting health care provider; flushing has been reported with chlorpropamide.
  • Caution patient to avoid exposure to sunlight and to use sunscreen or wear protective clothing to avoid photosensitivity reaction.
  • Advise patient that drug can cause dizziness and to use caution while driving or performing other tasks requiring mental alertness.
  • Remind patient to wear medical identification (eg, card, bracelet).

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