The FDA has approved Vybrique (IBSA), an oral film formulation of the phosphodiesterase type 5 (PDE5) inhibitor sildenafil, for treatment of erectile dysfunction (ED). Sildenafil oral tablets (Viagra, and generics) have been available since 1998. The manufacturer is promoting the new product as a "discreet, on-the-go" option that can be taken without water.

The FDA has authorized over-the-counter (OTC) sale of a nonmedicated alcohol-based gel (Eroxon – Futura) for treatment of erectile dysfunction (ED) in males ≥22 years old. Eroxon is the only FDA-approved OTC and topical treatment for erectile dysfunction. It is also available in the UK and the EU.

A reader asked us to review use of the phosphodiesterase-5 (PDE5) inhibitor sildenafil for treatment of Alzheimer's disease (AD).

The FDA has approved avanafil (Stendra – Vivus), an oral phosphodiesterase type-5 (PDE5) inhibitor, for treatment of erectile dysfunction. It is the fifth PDE5 inhibitor to be approved for this indication. Advertisements on Stendra’s website imply that it has a faster onset of action than other PDE5 inhibitors.

Sildenafil (Viagra), tadalafil (Cialis) and vardenafil (Levitra, Staxyn) have become the standard treatment for erectile dysfunction. Head-to-head comparisons of these agents are still lacking, but some differences between them and new recommendations for their dosing (see Table 2) are worth noting.

The FDA has approved the use of the phosphodiesterase-5 (PDE-5) inhibitor tadalafil (Cialis – Lilly) for treatment of signs and symptoms of benign prostatic hyperplasia (BPH) in men with or without erectile dysfunction. Tadalafil is approved for use under another brand name (Adcirca) for treatment of pulmonary arterial hypertension. The other PDE-5 inhibitors available in the US for treatment of erectile dysfunction (sildenafil [Viagra]; vardenafil [Levitra]) have also been reported to be effective for treatment of BPH signs and symptoms, but have not been approved for this indication by the FDA.

The phosphodiesterase type 5 (PDE5) inhibitor tadalafil (Cialis - Lilly) is now being promoted for once daily treatment of erectile dysfunction. Tadalafil differs from sildenafil (Viagra) and vardenafil (Levitra), the other PDE5 inhibitors marketed for erectile dysfunction in the US, in having a much longer duration of action.

BiDil (NitroMed), a fixed-dose combination of isosorbide dinitrate and hydralazine, was approved by the FDA for adjunctive use in the treatment of heart failure in black patients.Both drugs are oral vasodilators that have been used together off-label for many years to treat heart failure in patients not responding to other drugs.

The Medical Letter reported last year that sildenafil (Viagra - Pfizer) appeared to be effective for idiopathic pulmonary arterial hypertension (PAH), but confirmation from a controlled trial was needed. Now the results of such a study are about to be published, and the drug has been approved by the FDA for this indication under the trade name Revatio.

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.

The FDA recently announced that it was investigating 38 reports of loss of vision in men who took sildenafil (Viagra), which has been used to treat erectile dysfunction since 1998.

The ability of grapefruit juice to increase serum concentrations of drugs was first discovered during a study of the effect of ethanol on felodipine (Plendil) pharmacokinetics. Double-strength grapefruit juice used to disguise the taste of ethanol resulted in higher than expected serum concentrations of felodipine (DG Bailey et al, Clin Invest Med 1989; 12:357).

Alfuzosin hydrochloride (Uroxatral - Sanofi-Synthelabo) is now available in the US in a new formulation for once-daily treatment of benign prostatic hyperplasia (BPH). The drug has been used in Europe since 1987. Alpha₁-blockers cause relaxation of smooth muscle tone in the bladder neck, prostatic capsule and prostatic urethra, relieving symptoms of urinary obstruction.

Tadalafil (Cialis - Lilly Icos) is the third oral drug to be approved by the FDA for treatment of erectile dysfunction. It has a longer duration of action than sildenafil (Viagra) or vardenafil (Levitra - Medical Letter 2003; 45:77).

Vardenafil (Levitra -Bayer) is the second oral drug approved by the FDA for treatment of erectile dysfunction. Sildenafil (Viagra - Medical Letter 1998; 40:51), the first oral drug, has been available for 5 years. Pharmacokinetics, effectiveness, adverse effects, dosage and cost of the new drug are reviewed. Whether it offers any benefits over sildenafil is discussed.