The FDA has approved emtricitabine/tenofovir (Truvada - Gilead) and abacavir/lamivudine (Epzicom - GSK), two new fixed-dose combinations of nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs), for once-daily use in treatment of HIV infection. Two other fixed-dose NRTI combinations were previously approved for twice-daily dosing. Dual NRTI therapy is generally used in either an NNRTI (non-nucleoside reverse transcriptase inhibitor)-based or a PI (protease inhibitor)-based regimen.

Angiotensin receptor blockers (ARBs) are widely used as an alternative to angiotensin converting enzyme (ACE) inhibitors for treatment of hypertension because they lower blood pressure without inducing a cough. It has not been established that they provide the same cardiac benefits as ACE inhibitors. Recently, an editorial in the British Medical Journal suggested that ARBs may increase the risk of myocardial infarction.

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.