The FDA has approved the marketing of iloperidone (Fanapt – Vanda), a second-generation antipsychotic, for treatment of schizophrenia. Iloperidone is chemically related to risperidone (Risperdal, and others).

Current guidelines recommend use of a proton pump inhibitor (PPI) to decrease the risk of gastrointestinal bleeding in patients taking clopidogrel (Plavix) with aspirin. A recent issue of The Medical Letter considered whether omeprazole (Prilosec, and others) or other PPIs could interfere with the antiplatelet effect of clopidogrel. The conclusion was that patients taking both drugs should probably continue to do so until more data became available. Several new publications require reconsideration of that recommendation.

A recently published retrospective cohort study in patients 30-74 years old has led to headlines in the media warning that use of atypical antipsychotic drugs doubles patients’ risk of sudden cardiac death. Typical antipsychotics have long been associated with this risk. In this study, however, the incidence of sudden cardiac death was similar with typical and atypical antipsychotics: about 1 in 340 person-years among the patients who took typical (first generation) antipsychotics such as haloperidol (Haldol, and others) and 1 in 360 personyears among those who took atypical (second-generation) drugs such as olanzapine (Zyprexa), compared to 1 in 700 patient-years among otherwise similar nonusers of antipsychotic drugs. The risk increased with the dose of the drug and also with the age of the patient; the authors state that they did not include patients younger than 30 because sudden cardiac death is very rare in the younger age group.1

Second-generation drugs are less likely than first generation drugs to cause extrapyramidal symptoms, tardive dyskinesia and neuroleptic malignant syndrome, but more likely to cause weight gain and other metabolic abnormalities.2 Aripiprazole (Abilify)3 is least likely to prolong the QT interval, which is one of the mechanisms that could be responsible for the small increase in the absolute risk of sudden death among patients who take antipsychotic drugs.

In a patient with a good indication for its use, the consequences of not taking an antipsychotic drug may be greater than the risks of taking one.

1. WA Ray et al. Atypical antipsychotic drugs and the risk of sudden cardiac death. N Engl J Med 2009; 360:225.
2. Drugs for psychiatric disorders. Treat Guidel Med Lett 2006; 4:35.
3. Second-generation antipsychotics — aripiprazole revisited. Med Lett Drugs Ther 2005; 47:81.

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Retapamulin (re-tap'-a-mue'-lin; Altabax - Glaxo SmithKline) is a topical antibiotic recently approved by the FDA for treatment of bullous and non-bullous impetigo due to Streptococcus pyogenes and methicillin-susceptible Staphylococcus aureus. It is available as a 1% ointment by prescription only.

Sevelamer carbonate (Renvela – Genzyme), a buffered form of the anion-exchange resin sevelamer hydrochloride (Renagel – Genzyme),1 has been approved by the FDA for use in patients with chronic kidney disease on dialysis. According to the manufacturer, Renvela will replace Renagel, which has been shown to induce or exacerbate metabolic acidosis in patients on dialysis. Two randomized, crossover studies found the two sevelamer salts equivalent in their ability to lower serum phosphate.2,3 Patients taking the carbonate had higher serum bicarbonate concentrations and fewer gastrointestinal adverse effects. Sevelamer carbonate, which is available in 800-mg tablets, can be substituted for the hydrochloride salt gram for gram. Recent studies in patients beginning hemodialysis have suggested a possible mortality benefit for sevelamer compared to less expensive calcium- based phosphate binders,4,5 but some critics are skeptical.6

1. Phosphate binders. Med Lett Drugs Ther 2006; 48:15.
2. J Delmez et al. A randomized, double-blind, crossover design study of sevelamer hydrochloride and sevelamer carbonate in patients on hemodialysis. Clin Nephrol 2007; 68:386.
3. S Fan et al. Renvela (sevelamer carbonate) powder and Renagel (sevelamer hydrochloride) tablets: report of a randomized, cross-over study in chronic kidney disease (CKD) patients on hemodialysis (poster). American Society of Nephrology Renal Week. October 31- November 5 2007. San Francisco.
4. GA Block et al. Mortality effect of coronary calcification and phosphate binder choice in incident hemodialysis patients. Kidney Int 2007; 71:438.
5. AM Borzecki et al. Survival in end stage renal disease: calcium carbonate vs. sevelamer. J Clin Pharm Ther 2007; 32:617.
6. J Silver. The details bedevil DCOR. Kidney Int 2007; 72:1041.

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A variety of glucose monitoring devices have been used in an effort to reduce the hypoglycemia and wide glucose excursions that complicate insulin treatment of diabetes. Since the last Medical Letter issue reviewing such devices, more continuous glucose monitoring (CGM) systems have become available. Five devices available now, and two expected to be marketed soon, are listed in the table on page 14. The FDA has approved continuous glucose devices only for the observation of glucose trends.