Two highly effective methods have been developed, and are being further studied.
1) Reversible inhibition of sperm under guidance : Electrolytic effects tear sperm apart.
2) A Two drug Combo – phenoxybenzamine & thioridazine : Inhibit release of semen.

RISUG (reversible inhibition of sperm under guidance), is a medical male contraceptive procedure, that takes about 15 minutes in a doctor’s office. It is effective after about three days, and lasts for 10 or more years.

It is a reversible male contraceptive technique that features : no babies, no latex, no daily pill to remember, no hormones to interfere with mood or sex drive, no negative health effects whatsoever, and 100 percent effectiveness. If I were going to describe the properties of the perfect male contraceptive, it would certainly go something like this.

Doctor’s inject two common chemicals – styrene maleic anhydride and dimethyl sulfoxide – into each of a man’s vas deferens (the tubes carrying sperm out of the testicles). These chemicals form a polymer which thickens over the next 72 hours, like a pliable epoxy. The polymer gel (called Vasalgel in the US), does NOT harden or block the two vas deferens. Rather, the gel lines the wall of the tubes, allowing sperm to flow freely down the middle (which prevents pressure buildup in the testis), but because of the polymer’s pattern of negative/positive polarization, those sperm are torn apart through a poly-electrolytic effect.

With two little injections, this non-toxic jelly will sit there for 10+ years without you having to do anything else to not have babies. Set it and forget it. The poly-electrolytic effect might even have the side benefit of destroying HIV. It only takes two other injections, of water and baking soda into each vas deferens, to flush out the gel, and within two to three months, you’ve got all your healthy sperm again.

There is a clinical trial/mailing list sign-up from the Parsemus Foundation to get further information about this procedure’s development.

The Best Birth Control In The World Is For Men
techcitement.com

Another effective male contraceptive approach involves two drugs – phenoxybenzamine, a high blood pressure medication, and thioridazine, a discontinued schizophrenia medication – that have similar physiological effects, each act as a male contraceptive. Drs. Nnaemeka Amobi and Christopher Smith, at King’s College London, have been working since 1995 to discover precisely how they work.

As early as the 1950s, doctors with patients taking these drugs to regulate their blood pressure and mental health noticed that their patients became infertile. Per Drs. Amobi and Smith’s research, a pill taken two to three hours before intercourse would inhibit release of any semen whatsoever by relaxing the longitudinal muscles of the Wolffian duct system while still permitting the circular muscles to contract, resulting in a sphincter action of the circular muscles on the lax longitudinal ones so they clamp down on the tubes carrying sperm and semen. The effects dissipate within 16-24 hours.

Precisely because of the way it works, this medication could also potentially reduce or eliminate transmission of all semen-borne STDs (including HIV).

Could This Male Contraceptive Pill Make A Vas Deferens In The Fight Against HIV?
techcitement.com

First of all, the author does not apologize for the pun in the title. Secondly, it seems the author’s first male contraceptive article stirred up a lot of controversy about the hypothetical anti-HIV properties of his technique.