Rx Update
Mary Ross, R.Ph., M.B.A. and Barbara Mutnick, R.Ph.,
M.H.P.
Peer Review Status: Internally Peer Reviewed
Additional advantages of miconazole include its base and its cost. Miconazole has a corn starch base which is absorbent; nystatin has a nonabsorbent talc base. Talc can also be very irritating to the lungs if inadvertently inhaled. Miconazole powder is approximately one-fourth the cost of nystatin powder.
Troglitazone: A New Oral Antidiabetic Agent
Troglitazone (Rezulin[R]) is a newly approved thiazolidinlione
antidiabetic agent that targets insulin resistance. Troglitazone has
been FDA approved as adjunctive therapy for type II diabetic patients
who are inadequately controlled with insulin. Studies have shown that
some of these patients are able to reduce or discontinue their
insulin injections following the addition of troglitazone to their
regimen.
The adverse effects associated with troglitazone therapy are generally mild and include dizziness, edema, nausea and vomiting, diarrhea, palpitations, skin rash, and epigastric pain. When taken alone, hypoglycemia is not a commonly reported side effect. However, hypoglycemia is reported when troglitazone is given in combination with insulin or sulfonylureas. Abnormal lab values associated with troglitazone therapy include slight decreases in hemoglobin, hematocrit, and red blood cell counts, as well as liver function test abnormalities.
Troglitazone given in combination with cholestyramine results in a decrease in the absorption of troglitazone. Therefore, this combination is not recommended. Troglitazone also decreases plasma concentrations of terfenadine and its active metabolite, thereby reducing the effectiveness of terfenadine. The combination of troglitazone and oral contraceptives containing ethinyl estradiol and norethindrone reduces the plasma concentration of both agents. An unexpected pregnancy could result from this interaction. The extent of absorption of troglitazone is enhanced in the presence of food; therefore, the drug should be taken with food.
Troglitazone dosing should be initiated at 200 mg once daily in patients on insulin therapy. The dose may be increased after approximately 2 to 4 weeks if adequate response has not been achieved. The usual maintenance dose is 400 mg once daily with the maximum recommended dose of 600 mg per day. When fasting plasma glucose concentrations fall below 120 mg/dL, the manufacturer recommends the insulin dose be reduced 10 to 25%. Because this drug is minimally excreted in the urine, there is no need to adjust the dose of troglitazone in patients with renal insufficiency. However, due to its extensive hepatic metabolism, troglitazone should be used cautiously in patients with hepatic disease. Safe and effective doses in pediatric patients have not been established.
Troglitazone is available in 200 mg and 400 mg tablets.