In overactive bladder, involuntary bladder contractions due to detrusor overactivity result in urinary urgency, frequency, nocturia, and incontinence. The prevalence of the disorder increases with age. Nonpharmacologic treatment, including bladder training, urge suppression, pelvic floor muscle exercises, constipation management, modification of fluid intake, and avoidance of dietary irritants such as alcohol and caffeine, should be tried first.

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 Entadfi (Veru), a fixed-dose combination of the 5α-reductase inhibitor finasteride and the phosphodiesterase type 5 (PDE5) inhibitor tadalafil, for initial treatment of benign prostatic hyperplasia (BPH) in men with an enlarged prostate; use of the drug is limited to 26 weeks. Entadfi is the first 5α-reductase inhibitor/PDE5 inhibitor combination to become available in the US. Finasteride (Proscar, and generics) and tadalafil (Cialis, and generics) are also available separately.

About 60% of men ≥60 years old have clinically relevant prostatic enlargement due to benign prostatic hyperplasia (BPH). The goals of treatment are to decrease lower urinary tract symptoms and to prevent disease progression and complications such as acute urinary retention. The American Urologic Association's guidelines for treatment of BPH were recently updated.

View the Expanded Table: Some Drugs for Altitude Illness, Jet Lag, and Motion Sickness

The FDA has approved an intranasal gel formulation of testosterone (Natesto – Trimel/Endo) for replacement therapy in men with hypogonadism. Packaged in a metered-dose pump, Natesto is the first intranasal testosterone to become available in the US. Like other testosterone products, it is classified as a schedule III controlled substance. The FDA recently cautioned against using testosterone to treat low testosterone levels solely due to aging because the benefits and safety of such use have not been established, and there is a possible increased risk of myocardial infarction (MI) and stroke.

Patients planning to travel to other countries often ask for information about prevention of diarrhea, malaria, and other travel-related conditions. Vaccines recommended for travelers based on their destination, length of stay, and planned activities were reviewed in a previous issue.

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.

Prompted by the recent publication of 2 retrospective studies, the FDA has announced that it is investigating the risk of stroke, heart attack, and death in men taking FDA-approved testosterone products.1

The first study examined the records of 8709 men with low testosterone levels (<300 ng/dL) who underwent coronary angiography between 2005 and 2011; 1223 of these men started testosterone therapy after a median of 531 days following coronary angiography. Three years after coronary angiography, the Kaplan-Meier estimated cumulative percentages of men who died or had a myocardial infarction (MI) or ischemic stroke were 26% of those treated with testosterone and 20% of those who were not treated with the hormone, a hazard ratio of 1.29 (95% CI 1.04-1.58; P=0.02).2

The second study compared the rate of nonfatal MI during the 90 days after filling a prescription with the rate in the prior year in 56,000 men given a prescription for testosterone and in 167,000 given a phosphodiesterase type 5 inhibitor (sildenafil [Viagra] or tadalafil [Cialis]). In the testosterone group as a whole, the post/pre-prescription rate ratio was 1.36, but in men ≥65 years old it was 2.19 and in younger men with a history of heart disease it was 2.90. In men who received a prescription for sildenafil or tadalafil, the rate ratio was 1.08 for all ages, 1.15 for those ≥65 years old, and 1.40 for younger men with a history of heart disease.3

A recent meta-analysis of randomized, placebo-controlled trials of testosterone therapy also found an increased risk of cardiovascular-related events in men treated with the hormone (odds ratio [OR] 1.54; 95% CI 1.09-2.18); an analysis by funding source found that the risk was greater in trials not funded by the pharmaceutical industry (OR 2.06 vs. 0.89).4

1. FDA Drug Safety Communication January 31, 2014: FDA evaluating risk of stroke, heart attack and death with FDA-approved testosterone products. Available at www.fda.gov. Accessed February 24, 2014.

2. R Vigen et al. Association of testosterone therapy with mortality, myocardial infarction, and stroke in men with low testosterone levels. JAMA 2013; 310:1829.

3. WD Finkle et al. Increased risk of non-fatal myocardial infarction following testosterone therapy prescription in men. PLoS One 2014; 9:e85805.

4. L Xu et al. Testosterone therapy and cardiovascular events among men: a systematic review and meta-analysis of placebo-controlled randomized trials. BMC Med 2013; 11:108.

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The FDA has approved the use of a permanent prostatic urethral lift implant (UroLift – NeoTract) to relieve low or blocked urine flow in men ≥50 years old with benign prostatic hyperplasia (BPH).

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 FDA has approved use of tadalafil (Adcirca - Lilly/United Therapeutics) for treatment of pulmonary arterial hypertension (PAH).

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.