Sildenafil and Tadalafil Use for Raynauds and Digital Ulcers

What are sildenafil and tadalafil and how are they used?

Sildenafil and tadalafil are medications which are used to help relax blood vessels. They work by preventing the action of a chemical in your body, called phosphodiesterase type 5.

Why have I been given sildenafil or tadalafil?

Sildenafil and tadalafil are used as second-line treatments for Raynaud’s. They are also used for the treatment of digital ulcers, which are sores which appear on the fingers and toes. Digital ulcers are often seen in a condition called systemic sclerosis or scleroderma. Why digital ulcers form is complex but is in part due to poor blood flow in the fingers and toes. The drugs sildenafil and tadalafil reduces the number of new ulcers that appear.

How long will they take to work?

Most people will notice a response within a few weeks of taking one of these medications.

What dose do I take and how do I take it?

The dose will be decided by your rheumatologist. They are usually started at a lower dose and may be increased depending on your response.

Sildenafil is a tablet and is usually taken three times a day.

Tadalafil is a tablet and is taken once a day. Unless your doctor tells you otherwise, you can generally take tadalafil at a time of day that suits you.

If you have missed a dose, take it as soon as you remember. If it is nearly time for the next dose, do not take the one you missed. Take the next dose at the usual time. Do not double the dose.

Do I need any monitoring whilst on sildenafil or tadalafil?

You will need baseline blood tests to check your kidney and liver function. You will also need to have your blood pressure checked when you start one of these medications and if the dose is increased. There are no other monitoring requirements when taking these medications.

Possible risks and side effects

All medicines can cause unwanted side effects. The most common side effects include:

• Headache
• Muscle aches and pains
• Facial flushing
• Nose or throat symptoms
• Feeling sick (nausea) or being sick (vomiting), tummy (abdominal) discomfort
• Feeling faint or dizzy
• Blurred vision
• Nosebleeds
• The feeling of having a 'thumping heart' (palpitations)
• Increased menstrual bleeding.

If you experience any of the following, contact a doctor for medical attention straightaway:

• An allergic-type reaction such as a rash or swelling around your face
• Chest pains
• A sudden loss of vision or hearing
• An erection lasting for more than four hours.

Are sildenafil and tadalafil suitable for everyone?

Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking sildenafil or tadalafil it is important that your rheumatologist knows:

• If you have any other heart or blood vessel disease
• If you have low blood pressure
• If you have a condition which causes bleeding, such as a stomach ulcer
• If you have had an eye condition causing loss of vision
• If you have any problems with the way your liver works, or any problems with the way your kidneys work
• If you have had a stroke or a heart attack
• If you have any disease, injury or deformity of your penis

• If you have sickle cell disease
• If you have ever had bone marrow cancer or leukaemia
• If you are pregnant or breastfeeding
• If you have ever had an allergic reaction to a medicine.

Do sildenafil and tadalafil interfere with other medications? Sildenafil or tadalafil can interact with other medications including:

• Nitrate medications such as glyceryl trinitrate, isosorbide mononitrate and sodium nitroprusside used to treat angina and other heart conditions.
• Some antibiotic medicines such as rifampicin, erythromycin and clarithromycin
• Some medicines used to treat seizures such as phenytoin, phenobarbital and carbamazepine.
• Some medicines used to treat fungal infections such as ketoconazole and itraconazole.
• Protease inhibitors used to treat HIV such as ritonavir and saquinavir.
• Medicines used to treat hypertension (high blood pressure) such as metoprolol, irbesartan and enalapril.
• Alpha blockers (used to treat hypertension and some prostate problems) such as prazosin and doxazosin.
• High doses of alcohol
• Grapefruit juice
• Guanylate cyclase stimulators such as riociguat, used to treat pulmonary arterial hypotension.
• A recreational drug called a 'popper'.

Do sildenafil or tadalafil affect sexual function?

Studies on the effects of sildenafil on sexual function in women have shown mixed results. Some reported increasing sex arousal, while others show that it’s only very slightly better than taking a dummy pill, or that it doesn’t have any effect at all.

Tadalafil has not been shown to have an effect on sexual function in women.

When taking sildenafil or tadalafil men may experience erections when they are sexually aroused. If an erection lasts for greater than 4 hours you should seek medical attention straight away.

Do sildenafil and tadalafil affect fertility, pregnancy and breastfeeding?

There is no clear evidence to suggest that taking sildenafil or tadalafil reduces fertility in either women or men.