Erectile Dysfunction & Male Health

PDE5 Inhibitors: The NO–cGMP Pathway and the Nitrate Trap

Few drugs tell a cleaner story about signal transduction than the ones that treat erectile dysfunction. An erection is not a plumbing event so much as a chemical cascade — a whisper of nitric oxide that ends in a wave of smooth-muscle relaxation. The famous "little blue pill" does not start that cascade; it simply refuses to let the body switch it off. That single, elegant idea explains everything: why the drug only works with arousal, why it is first-line for erectile dysfunction, why the same pathway treats pulmonary hypertension — and why, combined with a nitrate, it can kill.

Second-Line Erectile Dysfunction Therapy and the Priapism Emergency

A sildenafil prescription works for most men — but not all. When the tablet fails, the reflex is to reach for a stronger dose or a different pill. The better move is to stop and think: was it even used correctly, and what silent drug or disease is sabotaging the erection in the first place? Beyond the PDE5 inhibitors lies a second tier of therapy that bypasses the whole nitric-oxide pathway — and carries its own dramatic risk. This is the chapter where a drug meant to produce an erection can produce one that will not end, and where an erection lasting more than four hours stops being a success and becomes a surgical emergency.

Testosterone, Hypogonadism and Male Sexual Health

Testosterone is one of the most requested — and most misunderstood — hormones in medicine. A man in his fifties feels tired, low and flat, reads about "low T" online, and asks for a prescription. Sometimes he genuinely needs it. Often he doesn't, and giving it would do real harm — thicken his blood, unmask a prostate cancer, and, paradoxically, make him infertile. This article applies the hypothalamic–pituitary–gonadal axis you met in Endocrine to three clinical problems: replacing testosterone when it is truly missing, recognising the man abusing it in the gym, and treating the sexual and fertility complaints that testosterone should — and should not — touch.