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The only forms of contraceptives currently available to men are condoms, the withdrawal method, vasectomy and abstinence. In other animals, castration is commonly used for contraception. Other forms of male contraception are in various stages of research and development.

[edit] Methods in development

• Reversible inhibition of sperm under guidance (RISUG) consists of injecting styrene maleic anhydride in dimethyl sulfoxide into the vas deferens and leads to long lasting sterility. A second injection washes out the substance and restores fertility. As of 2007^[update], RISUG is in Phase III of human testing.^[1]

• Vas-occlusive contraception consists of partially or completely blocking the vas deferens, the tubes connecting the epididymis to the urethra. While a vasectomy removes a piece of each vas deferens, the intra vas device (IVD) and other injectable plugs only block the tubes until the devices are removed.^[1]

• Heat-based contraception involves heating the testicles to a high temperature for a short period of time to prevent the formation of sperm.

• Adjudin, a non-toxic analog of lonidamine which, in tests on rats, has been shown to cause reversible infertility.^[2] The drug disrupts the junctions between nurse cells (Sertoli cells) in the testes and forming spermatids. The sperm are released prematurely and never become functional gametes. A new targeted delivery mechanism has made Adjudin much more effective.^[3]

• Multiple male hormonal contraceptive protocols have been developed. One is a combination protocol, involving injections of Depo-Provera to prevent spermatogenesis, combined with the topical application of testosterone gel to provide hormonal support.^[1][4] Another is a monthly injection of testosterone undecanoate, which recently performed very well in a Phase III trial in China.^[5][6]

• Research has been performed on interference with the maturation of sperm in the epididymis.^[7][8]

• Phenoxybenzamine has been found to block ejaculation, which not only gives it the potential to be an effective contraceptive, but could also lead to much cleaner sex. Studies have found that the quality of the semen is unaffected and the results are reversible by simply discontinuing the treatment. ^[9][10]

• Silodosin, an α1-adrenoceptor antagonist with high uroselectivity, has been shown to completely block ejaculation in human males while permitting the sensation of orgasm.

[edit] Abandoned research

• Gossypol, derived from cotton seeds, was used in trials by the Chinese government for about fifteen years. While it was found to be a reliable contraceptive, it has serious health effects, and ten to twenty percent of users become permanently sterile. Research on it as a temporary contraceptive has been abandoned.
• Zavesca (aka Miglustat 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. Zavesca showed no contraceptive effect in other mammals.^[11]

[edit] References

1. ^ ^{a b c} Robert Finn. "Male Contraceptive Methods Are in the Pipeline". Ob.Gyn. News 42:28 May 1, 2007. 
2. ^ Dolores D. Mruk and C. Yan Cheng. Sertoli-Sertoli and Sertoli-Germ Cell Interactions and Their Significance in Germ Cell Movement in the Seminiferous Epithelium during Spermatogenesis. Endocrine Reviews (2004) 25 (5): 747-806
3. ^ Mruk DD, Wong CH, Silvestrini B, Cheng CH (2006) A male contraceptive targeting germ cell adhesion Nature Medicine advance access 29 October 2006.
4. ^ Nuzzo R (2006) Beyond condoms: male hormonal contraceptives may finally be on track. Los Angeles Times, 16 October.
5. ^ Gu, Yi-Qun et al.. "A Multicenter Contraceptive Efficacy Study of Injectable Testosterone Undecanoate in Healthy Chinese Men". J Clin Endocrinol Metab 88:2 February 1, 2003. 
6. ^ Gu, Yi-Qun et al.. "Multicenter Contraceptive Efficacy Trial of Injectable Testosterone Undecanoate in Chinese Men". J Clin Endocrinol Metab 94:6 June 1, 2009. 
7. ^ Turner TT, Johnston DS, Jelinsky SA (2006) Epididymal genomics and the search for a male contraceptive Journal of Molecular and Cellular Endocrinology. Released as an Epub ahead of printing on 1 February 2006.
8. ^ Gottwald U, Davies B, Fritsch M, Habenicht UF (2006) New approaches for male fertility control: HE6 as an example of a putative target Journal of Molecular and Cellular Endocrinology. Released as an Epub ahead of printing on 23 January 2006. lIKE EWE
9. ^ Phenoxybenzamine-an effective male contraceptive ...[Contraception. 1984] - PubMed Result
10. ^ Prazosin, an adrenergic blocking agent inadequate ...[Contraception. 1988] - PubMed Result
11. ^ Amory JK, Muller CH, Page ST, Leifke E, Pagel ER, Bhandari A, Subramanyam B, Bone W, Radlmaier A, Bremner WJ. Miglustat has no apparent effect on spermatogenesis in normal men. Human Reproduction advance access 25 October 2006.

[edit] Further reading

• Male Contraception Information Project
• UCSB's SexInfo page on male contraception
• MaleContraceptives.org has a summary of experimental male contraceptive methods.
• Male contraceptive trial has 100% success in New Scientist, 6 October 2003.