Which of these is CORRECT regarding the effects of sildenafil?
Sildenafil is extensively metabolised by cytochrome P450 3A4 and 2C9. Drugs that inhibit these isoenzymes may increase sildenafil plasma levels. Erythromycin, a CYP3A4 inhibitor, has been shown to increase plasma sildenafil concentrations by 182%. Sildenafil has a low incidence of adverse effects, and these side effects are generally transient and mild to moderate in nature. In clinical trials the most common side effects were headache (16%), flushing (10%) and dyspepsia (7%). Some patients (about 3%) also reported changes in vision, predominantly colour tinge to vision, but also increased sensitivity to light or blurred vision. No cases of priapism were reported. The discontinuation rate due to adverse events among the treated patients was not significantly different from those receiving placebo (2.5% vs. 2.3%).
All the following are TRUE for a threepiece inflatable penile prosthesis except:
The infection rates for penile prosthesis are 1%–3%. The patient considering prosthesis implantation should be informed of the possibilities of infection and erosion, mechanical failure and migration of the device that usually require reoperation. Both the appearance of the flaccid penis and the erection produced by prostheses are different than normal. Penile prosthesis satisfaction rates are high (70%–87%).
The following are TRUE about Klinefelter’s syndrome except:
The Klinefelter’s syndrome is the most frequent sex chromosome abnormality. Testosterone levels may be normal or low. Germ cell presence and sperm production are variable in men with Klinefelter’s mosaicism, 46,XY/47,XXY. These patients have 50 times higher risk of germ cell tumours which usually contains non-seminomatous germ cells and present at an earlier age and seldom are gonadal in location.
The following are TRUE for Y microdeletions and infertility except:
Y deletions (Yq11 micro-deletions) were not found in normospermic men and thus have a clear-cut cause effect relationship with spermatogenic failure. The highest frequency is found in azoospermic men (8%–12%) followed by oligospermic (3%–7%) men. Deletions are extremely rare with a sperm concentration >5 millions of spermatozoa/mL. (approximately 0.7%). The most frequently deleted region is AZFc (approximately 65%–70%), followed by deletions of the AZFb and AZFb+c or AZFa+b+c regions (25%–30%) whereas deletions of the AZFa region are extremely rare (5%). The complete removal of the AZFa and AZFb regions is associated with severe testicular phenotype, Sertoli cell-only syndrome and spermatogenic arrest, respectively. The complete removal of the AZFc region causes a variable phenotype which may range from azoospermia to oligozoospermia. Classical AZF deletions do not confer risk for cryptorchidism or testis cancer.
Peyronie’s disease is a connective tissue disorder involving the growth of fibrous plaques in tunica albuginea of the penis. It affects up to 10% of all men. It’s more common in Caucasian men over the age of 40. It is associated with diabetes mellitus and smoking. There is evidence to suggest that the inflammation associated with Peyronie’s is at least partly mediated through the action of TGFβ. Pentoxifylline a possible medical treatment option is a TGβ1 inhibitor.
Surgery is very effective at correcting the curvature when the disease is in the chronic phase (93% success using plaque incision and grafting). Penile shortening greater than 1 cm occurred in only 25% and new onset ED in 15%. Even when previous surgery has failed salvage surgery in expert hand has a high success rate. A number of different graft materials have been used with success.
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