CHLORPROPAMIDE
| CHLORPROPAMIDE (klor-proe'pa-mide) Apo-Chlorpropamide  , Diabinese, Novopropamide Classifications: hormone; antidiabetic sulfonylurea; Therapeutic: antidiabetic; sulfonylurea Prototype: Glyburide Pregnancy Category: C |
Availability
100 mg, 250 mg tablets
Action
Longest-acting first-generation sulfonylurea compound. Lowers blood glucose by stimulating beta cells in pancreas to synthesize and release endogenous insulin. May potentiate available antidiuretic hormone (ADH) secretion, a property not shared by other sulfonylureas.
Therapeutic Effect
Antidiabetic effect is due to the ability of the drug to stimulate the beta cells of the pancreas to manufacture and release insulin. Therapeutic effectiveness is indicated by HbA1c levels >7%.
Uses
Stable non-insulin-dependent diabetes mellitus (type 2) in patients who cannot be controlled by diet alone and who do not have complications of diabetes.
Unlabeled Uses
Neurogenic diabetes insipidus.
Contraindications
Known hypersensitivity to sulfonylureas and to sulfonamides; diabetes complicated by severe infection; acidosis; severe renal, hepatic, or thyroid insufficiency; pregnancy (category C), lactation. Safe use in children not established.
Cautious Use
Older adult patients, Addison's disease, CHF, and hepatic porphyria.
Route & Dosage
| Antidiabetic Adult: PO Initial: 100–250 mg/d with breakfast, adjust by 50–125 mg/d q3–5d until glycemic control is achieved, up to 750 mg/d |
Administration
Oral- Give as a single morning dose with breakfast. To reduce GI adverse effects, drug may be prescribed as 2 or 3 doses and taken with meals.
- Store below 40° C (104° F), preferably at 15°–30° C (59°–86° F) in a tightly closed container, unless otherwise directed.
Adverse Effects (≥1%)
Body as a Whole: Flushing, photosensitivity, alcohol intolerance. GI: GI distress, anorexia, nausea, diarrhea, constipation, cholestatic jaundice. Hematologic: Leukopenia, thrombocytopenia, agranulocytosis. Metabolic: Hypoglycemia, antidiuretic effect (SIADH), dilutional hyponatremia, water intoxication. CNS: Drowsiness, muscle cramps, weakness, paresthesias. Skin: Rash, pruritus.Interactions
Drug: Adverse effects of oral anticoagulants, phenytoin, salicylates, nsaids may be increased along with those of chlorpropamide; thiazide diuretics may increase blood sugar; alcohol produces disulfiram reaction; probenecid, mao inhibitors may increase hypoglycemic effects. Herbal: Garlic, ginseng may increase hypoglycemic effects.Pharmacokinetics
Absorption: Readily from GI tract. Onset: 1 h. Peak: 3–6 h. Distribution: Highly protein bound; distributed into breast milk. Metabolism: In liver. Elimination: 80–90% in urine in 96 h. Half-Life: 36 h.Nursing Implications
Assessment & Drug Effects
- Monitor therapeutic effectiveness: Indicated by HbA1c levels >7%.
- Monitor blood and urine glucose to determine effectiveness of glycemic control.
- Lab tests: Periodic fasting and postprandial blood glucose; HbA1c every 3 mo; baseline and periodic hematologic and hepatic studies are advisable, particularly in patients receiving high doses. A CBC should be performed if symptoms of anemia appear.
- Report dizziness, shortness of breath, malaise, fatigue.
- Monitor for S&S of hypoglycemia (see Appendix F).
- Monitor I&O ratio and pattern: Infrequently, chlorpropamide produces an antidiuretic effect, with resulting severe hyponatremia, edema, and water intoxication. If fluid intake far exceeds output and edema develops (weight gain), report to the physician.
Patient & Family Education
- Report hypoglycemic episodes to physician. Because chlorpropamide has a long half-life, hypoglycemia can be severe, although onset is not as fast or as dramatic as with use of insulin.
- Report any of the following immediately to physician: skin eruptions, malaise, fever, or photosensitivity. Immediately report these symptoms to physician. A change to another hypoglycemic agent may be indicated.
- Do not self-dose with OTC drugs unless approved or prescribed by the physician.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; 
Prototype drug