PDE5 inhibitors: considerations for preference and long-term adherence.

INTRODUCTION: Erectile dysfunction (ED) is a highly prevalent condition affecting nearly one in five men worldwide. The advent of phosphodiesterase type 5 inhibitors (PDE5i) has revolutionised the ED treatment landscape and provided effective, minimally invasive therapies to restore male sexual function. MATERIALS AND METHODS: A pubmed search was performed of all English language articles from 1996 to present reviewing PDE5i, including pharmacokinetics, efficacy profiles and comparisons, where available. RESULTS: Currently available PDE5i in the United States include sildenafil, vardenafil, tadalafil and avanafil, each of which has unique side effect, pharmacokinetic and outcome profiles. Sildenafil is associated with increased rate of visual changes, vardenafil with QT prolongation and tadalafil with lower back pain. Avanafil and vardenafil orodispersible tablet rapidly achieve peak plasma concentration, which results in faster onset of action, whereas tadalafil exhibits the longest half-life. First time response to PDE5i is approximately 60-70%, with no significant differences in efficacy noted among therapies. The literature does not clearly demonstrate a preference for one drug. High-treatment success rates (89%) were reported when patients were prescribed all available PDE5i. Daily dosing with tadalafil is associated with improved erectile function (EF) over time. Finally, novel modes of patient-provider interaction, including internet-based education, communication and prescribing, may also improve long-term adherence. CONCLUSIONS: PDE5i represent first line therapy for ED with excellent overall efficacy and satisfactory side effect profiles. Enhanced communciation, coupled with increased knowledge of drug characteristics, comparative treatment regimens and optimal prescribing patterns, offer compelling tools to improve long-term treatment success.

Failure to attain stretched penile length after intracavernosal injection of a vasodilator agent is predictive of veno-occlusive dysfunction on penile duplex Doppler ultrasonography.

Penile duplex Doppler ultrasound (PDDU) assesses the etiology of erectile dysfunction. Peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) are common PDDU parameters. We assessed whether stretched penile length (SPL) in the flaccid state and measured penile length at peak erection after intracavernosal injection (ICI) of a vasodilator during PDDU correlated with the etiology of erectile dysfunction. We performed a retrospective review of 93 patients who underwent PDDU for erectile dysfunction. Normal and stretched penile length were measured, both at a flaccid state prior to ICI and at peak erection during PDDU. Collected data included patient demographics, vascular, and anatomic parameters. The mean age was 52 years. SPL was equivalent to peak penile length after ICI in 60 patients (65%, group 1) and did not match in 33 (35%, group 2). There were no significant differences between the two groups in terms of flaccid, stretched, and post-ICI erect penile lengths, IIEF score, PSV, percent rigidity or tumescence, and vasodilator dose used. Patients in group 2 had less of a change in penile length from flaccid to erect state (36% vs. 44%, p = 0.02), higher EDV (12.0 vs. 8.5, p = 0.041), lower RI (0.6 vs. 1.0, p = 0.046), and more veno-occlusive dysfunction (82% vs. 53%, p = 0.001). On multivariate analysis, failure to reach maximum SPL at peak ICI erection (OR 2.255, CI 1.191-4.271, p = 0.0126), EDV (OR 1.281, CI 1.115-1.471, p < 0.001) and RI (OR 0.694, CI 0.573-0.723, p = 0.009) predicted veno-occlusive dysfunction. Failure to reach maximal SPL during PDDU using ICI with a vasodilator agent predicted veno-occlusive dysfunction, which is independent of both penile rigidity and tumescence. This measurement could serve as another diagnostic tool for predicting veno-occlusive dysfunction when PDDU is not readily available. Limitations include the subjective nature of penile measurements and different PGE1 doses used.

Risks for bacteremia and urinary tract infections in young febrile children with bronchiolitis.

OBJECTIVE: To compare the risks for bacteremia and urinary tract injections (UTI) in young febrile children with and without bronchiolitis. DESIGN: A prospective cohort study. SETTING: The emergency departments of 3 pediatric referral hospitals. PATIENTS: A convenience sample of 432 previously healthy febrile patients aged 24 months or younger. Patients were divided into groups, based on the presence (n = 163, bronchiolitis group) or absence (n = 269, control group) of wheezing and/or retractions on examination. Blood cultures were obtained from all patients, and urine cultures were obtained from female patients, and male patients aged 6 months or younger. Chest radiographs were obtained on patients with lower respiratory tract signs, and those with lobar pneumonias were excluded (7 wheezing and 8 nonwheezing patients), leaving 156 patients with bronchiolitis and 261 control patients. OUTCOME MEASURES: Growth of any bacterial pathogens from the blood or 10(4) colony-forming units per milliliter or more from the urine. RESULTS: None of the 156 patients with bronchiolitis had bacteremia (95% confidence interval, 0%-1.9%) vs 2.7% of the 261 controls (95% confidence interval, 1.1%-5.4%; P = .049); 1.9% of the patients with bronchiolitis had UTI vs 13.6% of the controls (odds ratio, 0.12; 95% confidence interval, 0.02-0.55; P = .001). None of the subset of patients with bronchiolitis aged 2 months or younger (n = 36) had bacteremia or UTI; however, there were not enough of these younger patients to make statistically conclusive comparisons. CONCLUSIONS: Previously healthy febrile children aged 24 months or younger with bronchiolitis are unlikely to have bacteremia or UTI. Therefore, routine cultures of the blood and urine in these patients are unnecessary. More data are needed regarding the subset of febrile infants aged 2 months or younger with bronchiolitis.

Risk factors for cerebral edema in children with diabetic ketoacidosis. The Pediatric Emergency Medicine Collaborative Research Committee of the American Academy of Pediatrics.

BACKGROUND: Cerebral edema is an uncommon but devastating complication of diabetic ketoacidosis in children. Risk factors for this complication have not been clearly defined. METHODS: In this multicenter study, we identified 61 children who had been hospitalized for diabetic ketoacidosis within a 15-year period and in whom cerebral edema had developed. Two additional groups of children with diabetic ketoacidosis but without cerebral edema were also identified: 181 randomly selected children and 174 children matched to those in the cerebral-edema group with respect to age at presentation, onset of diabetes (established vs. newly diagnosed disease), initial serum glucose concentration, and initial venous pH. Using logistic regression we compared the three groups with respect to demographic characteristics and biochemical variables at presentation and compared the matched groups with respect to therapeutic interventions and changes in biochemical values during treatment. RESULTS: A comparison of the children in the cerebral-edema group with those in the random control group showed that cerebral edema was significantly associated with lower initial partial pressures of arterial carbon dioxide (relative risk of cerebral edema for each decrease of 7.8 mm Hg [representing 1 SD], 3.4; 95 percent confidence interval, 1.9 to 6.3; P<0.001) and higher initial serum urea nitrogen concentrations (relative risk of cerebral edema for each increase of 9 mg per deciliter [3.2 mmol per liter] [representing 1 SD], 1.7; 95 percent confidence interval, 1.2 to 2.5; P=0.003). A comparison of the children with cerebral edema with those in the matched control group also showed that cerebral edema was associated with lower partial pressures of arterial carbon dioxide and higher serum urea nitrogen concentrations. Of the therapeutic variables, only treatment with bicarbonate was associated with cerebral edema, after adjustment for other covariates (relative risk, 4.2; 95 percent confidence interval, 1.5 to 12.1; P=0.008). CONCLUSIONS: Children with diabetic ketoacidosis who have low partial pressures of arterial carbon dioxide and high serum urea nitrogen concentrations at presentation and who are treated with bicarbonate are at increased risk for cerebral edema.