PDE5 inhibitors and brain tumours

PDE5 inhibitors are drugs used to treat erectile dysfunction and pulmonary arterial hypertension. But, their use in brain tumour treatment is being investigated. Here we discuss PDE5 inhibitors and brain tumours.

On this page:

• What are PDE5 inhibitors?
• Types of PDE5 inhibitors
• PDE5 inhibitors and brain tumours

What are PDE5 inhibitors?

PDE5 stands for phosphodiesterase 5. This is an enzyme found in the body that helps regulate blood flow and cell signalling.

PDE5 inhibitors stop the PDE5 enzyme from working. This increases blood flow by relaxing the blood vessels.

Because of this effect, PDE5 inhibitors are useful for treating conditions where low blood flow is a problem.

These drugs are often used to treat erectile dysfunction and pulmonary arterial hypertension.

Types of PDE5 inhibitors

Some types of PDE5 inhibitors are:

Sildenafil (Viagra®, Revatio®)

Sildenafil is often used to treat erectile dysfunction. It works by temporarily increasing blood flow to the penis.

Sildenafil for erectile dysfunction is more widely known by the brand name Viagra. It’s available on prescription and you can buy it at pharmacies.

Sildenafil is also sometimes prescribed for pulmonary hypertension. This is high pressure in the arteries that supply blood to the lungs. This high pressure can damage the heart.

Sildenafil treats this by helping your chest’s blood vessels to relax and relieve pressure.

When used for pulmonary hypertension, sildenafil is often called by the brand name Revatio.

Tadalafil (Cialis®, Adcirca®)

Tadalafil is used to treat erectile dysfunction, symptoms of an enlarged prostate, and pulmonary arterial hypertension.

When used to treat erectile dysfunction, it often goes by the brand name Cialis. It comes in both pill and liquid form, and both are only available on prescription.

When used to treat the symptoms of an enlarged prostate, tadalafil relaxes the prostate and bladder muscles.

When used to treat pulmonary arterial hypertension, tadalafil often goes by the brand name Adcirca and can only be given with a prescription.

It helps treat the condition by widening the blood vessels of the lungs, helping reduce pressure and allowing more oxygen to get into the blood in the lungs.

Vardenafil (Levitra®)

Vardenafil is often used as an erectile dysfunction treatment. Similar to sildenafil and tadalafil, it temporarily increases blood flow to the penis.

Sildenafil for erectile dysfunction is often called Levitra, a brand name for the drug. It’s a prescription-only medication.

PDE5 inhibitors and brain tumours

The Repurposing Drugs in Oncology project (ReDO) is working to investigate whether existing drugs could be effective in cancer treatment.

When looking at PDE5 inhibitors, ReDO is interested in how they affect the blood-brain barrier.

An issue with certain brain tumour treatments is they have trouble crossing the blood-brain barrier. This barrier exists to protect the brain, only allowing certain helpful nutrients and molecules through and stopping harmful substances from entering the brain.

If certain brain tumour treatments are seen by the body as harmful, it won’t let them cross the blood-brain barrier.

But, PDE5 inhibitors are believed to increase the permeability of the blood-brain barrier. This could allow certain drugs to cross into the brain and be more effective.

So, ReDO recommends further clinical research, particularly in the case of tumours like glioblastoma, to see if the drugs could help to enhance other treatments.

But, currently, NICE doesn’t recommend PDE5 inhibitors as a treatment for brain tumours.

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