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Abstract(s)
A presente monografia consiste numa revisão bibliográfica acerca o efeito dos inibidores da fosfodiasterase 5 (PDE5i) na fertilidade masculina, isto é, da forma como o sildenafil, o vardenafil, o tadalafil e o avanafil interferem nos parâmetros do esperma humano, nomeadamente, no número de espermatozóides, no volume de ejaculado, na motilidade dos espermatozóides, na sua viabilidade, entre outros. Os PDE5i orais são fármacos utilizados no tratamento da disfunção erétil (DE), que devido ao seu perfil de segurança e eficácia se tornaram na terapêutica de primeira linha desta patologia. A sua estrutura química é semelhante ao segundo mensageiro celular guanosina-3’-5’-monofosfato cíclico (GMPc), e por isso, uma vez administrados irão ligar-se competitivamente às fosfodiesterases 5 (PDE5), presentes em vários tecidos do organismo, particularmente nas células musculares lisas dos corpos cavernosos. Aquando da ligação entre estes há inibição da hidrólise do GMPc, aumentando a sua concentração nas células do músculo liso, que resulta na diminuição do cálcio intracelular impossibilitando a formação do complexo cálcio-calmudolina (Ca-Cam), consequentemente, sucede-se o relaxamento do músculo liso promovendo a ereção do pénis. O uso destes PDE5i ainda causa algumas opiniões controversas no seio da comunidade científica, aquando da sua toma por homens com problemas de fertilidade, podendo tal ser comprovado através dos estudos in vivo e in vitro apresentados. Esta monografia tem como finalidade evidenciar os efeitos benéficos e nocivos dos PDE5i na fertilidade masculina.
This monograph is a bibliographic revision about the effects of phosphodiesterase inhibitors type 5 (PDE5i) on male fertility that is how sildenafil, vardenafil, tadalafil and avanafil interfere with the parameters of human sperm, namely, the spermatozoa numbers and its motility and viability and the total ejaculate volume, among others. The oral PDE5i are medicines which are used in the treatment of erectile dysfunction. This is a first-line therapy for this pathology due to its safety profile and treatment efficiency. Its chemical structure is similar to the intracellular second messenger 3',5'-cyclic guanosine monophosphate (cGMP) and so once administered they will competitively connect with the phosphodiesterase type 5(PDE5) which is presented in multiple organism tissues particularly on the smooth muscular cells of the corpus cavernosum. When this connection occurs there is an inhibition of hydrolysis of GMPc, increasing its concentration on smooth muscle cells. Additionally, there is a decreasing in intracellular calcium, disabling the formation of calcium calmodulin complex (Ca-Cam). Thereafter the relaxation of the smooth muscle leads to the penis erection. The use of these medicines for male fertility also cause some controversial opinions within the scientific community and this could be explained by studies in vivo and in vitro. This monograph presents the contrast between the benefits and the adverse effects of PDE5i in the male fertility.
This monograph is a bibliographic revision about the effects of phosphodiesterase inhibitors type 5 (PDE5i) on male fertility that is how sildenafil, vardenafil, tadalafil and avanafil interfere with the parameters of human sperm, namely, the spermatozoa numbers and its motility and viability and the total ejaculate volume, among others. The oral PDE5i are medicines which are used in the treatment of erectile dysfunction. This is a first-line therapy for this pathology due to its safety profile and treatment efficiency. Its chemical structure is similar to the intracellular second messenger 3',5'-cyclic guanosine monophosphate (cGMP) and so once administered they will competitively connect with the phosphodiesterase type 5(PDE5) which is presented in multiple organism tissues particularly on the smooth muscular cells of the corpus cavernosum. When this connection occurs there is an inhibition of hydrolysis of GMPc, increasing its concentration on smooth muscle cells. Additionally, there is a decreasing in intracellular calcium, disabling the formation of calcium calmodulin complex (Ca-Cam). Thereafter the relaxation of the smooth muscle leads to the penis erection. The use of these medicines for male fertility also cause some controversial opinions within the scientific community and this could be explained by studies in vivo and in vitro. This monograph presents the contrast between the benefits and the adverse effects of PDE5i in the male fertility.
Description
Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2016
Keywords
Disfunção erétil Inibidores da fosfodiesterase 5, Espermatozóides Fertilidade masculina Motilidade Capacitação Mestrado Integrado - 2016