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I don't think there is any medicine which reverses the block. Dear before coming to any conclusions kindly get yourself examined by a doctor . You need to get your blood tested for hormones. Once diagnosis is made that is what problem exactly you have, treatment can be directed accordingly. If tubes are blocked and your testes are producing sperms then sperms can be collected from tube or testis through needle and ICSI
(assisted reproductive technique ) can be done . But if testes is not producing sperms ...donor semen and adoption are only options. Take care.