Rx Update: January 2000
Mary Ross, R.Ph., M.B.A.
Peer Review Status: Internally Reviewed
The most common adverse reactions reported with quinupristin/dalfopristin administration are infusion-related. They include: inflammation at the infusion site (42%); pain at the infusion site (40%); edema at the infusion site (17%); infusion site reaction (13%); and thrombophlebitis (2.4%). Infusion site reactions were most commonly seen in patients with peripheral infusions. Quinupristin/dalfopristin should be diluted in 250 ml of D5W and administered over 60 minutes. A more concentrated solution may be used only if quinupristin/dalfopristin is administered through a central line. If moderate to severe venous irritation occurs following peripheral administration, the drug may be diluted in a larger volume of D5W (e.g., 500 ml), the infusion site may be changed, or the drug may be infused through at PICC or central venous catheter. The line should be flushed before and after administration with D5W to minimize venous irritation. DO NOT FLUSH with saline or heparin after quinupristin/dalfopristin administration because it is not compatible with these solutions. Quinupristin/dalfopristin should not be administered with any other medications through a y-site unless compatibility with both the drug and diluent are established. Arthralgia, myalgia, nausea, diarrhea, and vomiting have also been frequently reported.
Quinupristin/dalfopristin should not be used in patients who are allergic to quinupristin, dalfopristin, or other streptogramins. Quinupristin/dalfopristin significantly inhibits cytochrome P450 3A4 and may interact with medications that are metabolized through this enzyme (e.g., midazolam, astemizole, nifedipine, cisapride, cyclosporine).
The recommended dose of quinupristin/dalfopristin for VREF is 7.5 mg/kg intravenous over 60 minutes every 8 hours. Dosage adjustments are not required for patients with renal insufficiency or who are undergoing peritoneal dialysis. Dosage adjustments may be required for patients with hepatic cirrhosis. Quinupristin/dalfopristin is available as a 500 mg vial ( a fixed combination of 150 mg quinupristin and 350 mg dalfopristin). At UIHC the prescribing of quinupristin/dalfopristin requires Infectious Diseases approval.
There are several major concerns regarding the safety of using cilostazol in the general population. The first concern is that cilostazol is a phosphodiesterase III inhibitor, and it has been observed that there has been an increase in mortality in congestive heart failure patients receiving other phosphodiesterase III inhibitors. For this reason, the use of cilostazol is contraindicated in patients with congestive heart failure of any severity. Another concern is the potential for serious drug-drug interactions. Cilostazol is highly protein bound and is metabolized by hepatic cytochrome P-450 enzymes. Medications that inhibit cytochrome P-450 enzymes (e.g., ketoconazole, itraconazole, erythromycin, diltiazem, and omeprazole) will increase the levels of cilostazol. The most commonly reported adverse effects associated with cilostazol include headache, diarrhea, abnormal stools, dizziness, and palpitations.
The recommended dose of cilostazol is 100 mg twice daily taken at least 30 minutes before or two hours after a meal. A dose of 50 mg twice daily should be considered in patients who are concomitantly receiving medications that inhibit cytochrome P-450 enzymes. The dose of cilostazol does not need to be adjusted in patients with mild hepatic or renal impairment. The need for dosage adjustments has not been evaluated in patients with moderate to severe hepatic or renal dysfunction.
Cilostazol is available as 50 mg and 100 mg tablets.