The presence of side effects during pharmacological treatment is unfortunately a quite common problem. In this review, we focused our attention on adverse events related to 5 alpha-reductase (5α-R) inhibitors (i.e., finasteride and dutasteride), approved for the treatment of benign prostatic hyperplasia and androgenetic alopecia (AGA).

Although these drugs are generally well tolerated, many reports described adverse effects in men during treatment, such as sexual dysfunction and mood alteration. In addition, it has been also reported that persistent side effects may occur in some AGA patients. This condition, termed post-finasteride syndrome (PFS) is characterized by sexual side effects (i.e., low libido, erectile dysfunction, decreased arousal and difficulty in achieving orgasm), depression, anxiety and cognitive complaints that are still present despite drug withdrawal. Indeed, some national agencies (e.g., Swedish Medical Products Agency, the Medicines and Healthcare Products Regulatory Agency of UK and the U.S. Food and Drug Administration) required to include multiple persistent side effects within the finasteride labels.

As here reported, these observations are mainly based on self-reporting of the symptomatology by the patients and few clinical studies have been performed so far. In addition, molecular mechanisms and/or genetic determinants behind such adverse effects have been poorly explored both in patients and animal models. Therefore, results here discussed indicate that PFS is an emerging clinical problem that needs to be further elucidated.

不幸的是，在药物治疗过程中出现副作用是一个非常普遍的问题。在这篇综述中，我们将注意力集中在与5种α-还原酶（5α-R）抑制剂（即非那雄胺和度他雄胺）有关的不良事件上，这些抑制剂被批准用于治疗良性前列腺增生和雄激素性脱发（AGA）。

尽管这些药物通常具有良好的耐受性，但许多报道都描述了治疗期间男性的不良反应，例如性功能障碍和情绪改变。此外，也有报道称某些AGA患者可能会出现持续的副作用。这种称为非那雄胺后综合征（PFS）的疾病的特征是性副作用（即性欲低下，勃起功能障碍，唤醒感降低和难以达到性高潮），抑郁，焦虑和认知障碍，尽管停药仍然存在。实际上，一些国家机构（例如，瑞典医疗产品局，英国药品和保健产品监管局以及美国食品和药物管理局）要求在非那雄胺标签中包括多种持久性副作用。

如此处报道的，这些观察结果主要基于患者对症状的自我报告，迄今为止很少进行临床研究。此外，在患者和动物模型中均未充分研究这种不良反应背后的分子机制和/或遗传决定因素。因此，此处讨论的结果表明PFS是一个正在出现的临床问题，需要进一步阐明。