Tadalafil

What it is

Tadalafil is a PDE5 inhibitor. Blocking the breakdown of cyclic GMP allows smooth muscle in the blood vessels of the penis and prostate to relax, improving penile blood flow during arousal and easing urinary symptoms of prostate enlargement. It is used for erectile dysfunction and for benign prostatic enlargement.

Used for

• Erectile function
• Prostate

What to know while taking it

Food makes no meaningful difference to absorption, and the drug stays active far longer than others in its class, so its blood-pressure-lowering effect persists well beyond the day it is taken. Grapefruit and grapefruit juice raise its levels. Alongside tamsulosin or amlodipine the combined fall in blood pressure can cause dizziness on standing. It must never be combined with nitrates, including glyceryl trinitrate, because the resulting drop in blood pressure can be dangerous. Back and muscle ache are common in the first day or two and usually settle.

When to see a doctor

Chest pain during sex, fainting, sudden change in vision or hearing, or an erection that does not subside need urgent medical attention. Back or muscle pain that persists beyond a couple of days, or repeated dizziness on standing, should be reviewed by a doctor.

Worth knowing

• Never with nitrates
• Avoid grapefruit
• Back and muscle ache are common