Serious adverse interactions between drugs continue to be reported. Many of these are due to inhibition or induction of cytochrome P450 (CYP) enzymes, particularly CYP3A4. CYP3A is thought to be involved in the metabolism of more than 50 percent of currently prescribed drugs.2 CYP3A4, which is more abundantly expressed than CYP3A5, accounts for most CYP3A activity in vivo.

Hyperphosphatemia in end-stage renal disease can lead to secondary hyperparathyroidism, renal osteodystrophy, metastatic calcification and cardiovascular mortality. addition to dietary restriction of phosphorus and hemodialysis, drugs that bind phosphates in the gut are usually needed as well. Aluminum hydroxide is no longer recommended for long-term use because of concerns about its toxicity.

Decitabine (Dacogen - MGI Pharma), a pyrimidine nucleoside analog of cytidine, was approved by the FDA as an orphan drug for treatment of myelodysplastic syndromes (MDS), a heterogeneous group of clonal hemopathies that decrease production of normal blood elements (red cells, white cells and platelets) and are associated with a risk of progression to acute leukemia.

The FDA has approved an extended-release formulation of minocycline (Solodyn - Medicis) for once-daily treatment of non-nodular moderate to severe acne.

Cataracts are the leading cause of blindness worldwide because cataract surgery is not available to most people in developing countries.

Options in screening for colon cancer include fecal occult blood tests, flexible sigmoidoscopy, colonoscopy, computed tomography (CT) colonography and fecal DNA tests. Since the last Medical Letter article on this subject, more data have become available on colonography.

Continued use of a long-acting beta-2 agonist for treatment of asthma may cause down-regulation of the beta-2 receptor with loss of the bronchoprotective effect from rescue therapy with a short-acting beta-2 agonist. After a large study (SMART) found an increased risk of asthma-related deaths in patients receiving the long-acting beta-2 agonist salmeterol, a boxed warning was added to the labeling of all medications containing a long-acting beta-2 agonist. Now the FDA has completed a meta-analysis of 110 asthma treatment studies in 60,954 patients taking any of the long-acting beta-2 agonist...

Since publication of our recent article on antiviral drugs for influenza, increased levels of resistance to oseltamivir (Tamiflu) have been detected in influenza A H1N1 strains.

Effective treatment of hypertension can prevent organ damage and death. The choice of drugs for initial treatment continues to be controversial.

A little more than a year ago, The Medical Letter reported the results of an FDA meta-analysis which found that use of a long-acting beta-2 agonist (LABA) such as salmeterol (Severent) or formoterol (Foradil) in patients with asthma was associated with an increased risk of a composite endpoint of asthma-related death, intubation or hospitalization; the highest risk was in children 4-11 years old.There was no significant increase in risk when a long-acting beta-2 agonist was used with an inhaled corticosteroid.The Medical Letter recommended that long-acting beta-2 agonists should not be used as...