Tadalafil: erection problems, prostate symptoms and safety

Tadalafil is a tablet mainly used to treat erection problems. Under the same name, doctors also prescribe it for benign prostate enlargement and for pulmonary arterial hypertension, a condition in which the blood pressure in the lung arteries is high. The brand names listed by the NHS are Cialis, Cialis Together and Adcirca.

It belongs to the group of medicines that work by relaxing blood vessels and increasing blood flow. It helps with erections only when there is sexual stimulation; it does not cause one on its own.

Tadalafil is a prescription medicine. The NHS notes that in some circumstances it can be supplied after a consultation with a pharmacist, who will ask about your health and other medicines first.

For erection problems taken as needed, the NHS describes 1 tablet about 30 minutes before sex, never more than 1 tablet a day. Some people are prescribed a once-daily tablet taken at the same time every day. Swallow it whole with water.

The effects can last up to 36 hours, which is why a second tablet on the same day is not advised.

• If you miss a daily dose, take it when you remember unless the next dose is close, then skip it. Never take 2 doses to make up for a missed one.

• An extra dose can be dangerous. Call NHS 111 straight away if you have taken more than prescribed.

• Prostate and pulmonary hypertension doses are set by the prescriber for the individual.

The most important safety point is that tadalafil is not usually prescribed together with nitrates, particularly glyceryl trinitrate used for chest pain. Both lower blood pressure, and together they can cause a dangerous drop. Tell any doctor, dentist or paramedic who treats you that you have taken tadalafil, because it can affect emergency treatment for chest pain for up to 36 hours.

The same applies to poppers (amyl nitrate). The NHS says taking tadalafil with poppers or illegal drugs such as amphetamines, ecstasy and cocaine can increase the risk of serious side effects.

Tadalafil may be unsuitable if you have had an allergic reaction or serious side effect to it, a recent heart attack or stroke, low blood pressure or uncontrolled high blood pressure, liver or kidney problems, a blood cancer such as leukaemia or multiple myeloma, sickle cell disease, or previous loss of vision from reduced blood flow to the optic nerve. A deformity of the penis that makes erections painful is also on the list.

Pregnancy and breastfeeding are reasons to avoid it.

Common effects include indigestion, muscle aches and limb pain, back pain, a blocked nose, facial flushing and headache.

Rare serious effects include allergic reaction, sudden hearing or vision changes, palpitations, breathlessness, chest pain, seizures and a painful erection that will not go away (priapism). The NHS says to call NHS 111 if you think you are having serious side effects; a painful prolonged erection, chest pain or a severe allergic reaction needs emergency care.

Suspected side effects can be reported through the Yellow Card scheme.

Besides nitrates, the NHS lists anticonvulsants, medicines for pulmonary hypertension, antibiotics such as rifampicin, erythromycin and clarithromycin, antifungals, antiretrovirals and other prostate or erection medicines as needing care. Do not drink grapefruit juice while taking it.

Alcohol can lower blood pressure and cause dizziness or light-headedness, and drinking too much can also make erections harder to achieve. Tadalafil does not usually affect driving, but wait for dizziness to pass.

Erection problems can be an early sign of heart disease, diabetes or high blood pressure. The NHS advises a check-up with your doctor within 6 months of starting if you obtained tadalafil without a prescription. Related conditions are covered in the guide on erectile dysfunction.