on the safety and effectiveness of using ultrasound treatments to kill sperm has undergone since the idea originally came about following experiments in the 1970s by mostafa s. fahim who noticed ultrasound killed microbes and decreased fertility. as of 2012 a study conducted on rats found that two 15-minute treatments of ultrasound delivered 2 days apart in a warm salt bath effectively lowered their sperm count to below fertile levels. another small study involved dogs, and found that after three ultrasound applications the dogs' ejaculate contained no sperm. further experiments on its effectiveness on humans, the longevity of the results, and its safety have yet to be conducted. abandoned research miglustat (zavesca or nb-dnj) is a drug approved for treatment of several rare lipid storage disorder diseases. in mice, it provided effective and fully reversible contraception. but it seems this effect was only true for several genetically related strains of laboratory mice. miglustat showed no contraceptive effect in other mammals. silodosin, an α1-adrenoceptor antagonist with high uroselectivity, approved by the fda to treat benign prostatic hyperplasia (bph), has been shown to decrease sperm count when taken in at 5 times normal doses. impact it is predicted that introduction of a long-acting reversible contraception for males could decrease the rate of unintended pregnancy.