A challenge to the concept that the use of calcium channel blockers causes reversible male infertility

The objective of this study was retrospectively to evaluate both in-vitro fertilization (IVF) and non-IVF cycles in which the male partner had been taking calcium channel blockers, either to confirm or refute previous data from another centre, suggesting that these drugs cause a severe but reversible subfertility problem in the male. These drugs were found to inhibit expression of mannose-ligand binding receptors, thus preventing spermatozoa from attaching to the zona pellucida; they were postulated to cause failed fertilization based on one case having this defect, in whom a return to normal was achieved after stopping the drug. However, the couple did not undergo a cycle with IVF to see if fertilization now occurred. The data presented here demonstrated fertilization in all patients having IVF who were taking calcium channel blockers. The subsequent pregnancy rate per transfer was 17.4%. Also, five out of 11 (45.4%) non-IVF patients conceived after correction of various female factors. Failure of the other six patients to conceive could be explained by other confounding factors, especially oligoasthenozoospermia. Taking into consideration other data suggesting poor fertilization when this mannose-ligand binding receptor abnormality was demonstrated, we propose the possibility that this defect, when not associated with calcium channel blockers, may be associated with some other cryptic factor that causes poor fertilization. According to our hypothesis, calcium channel blockers might cause the problem in mannose expression but also adversely affect some other factor that is deficient when non-drug related abnormalities in mannose-ligand binding expression are found.