Sildenafil
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What is sildenafil?
Sildenafil (brand name: Revatio®, Sildenafil PHT Apotex, Sildatio PHT) Sildenafil belongs to a group of medicines called 5-phosphodiesterase inhibitors. It works by relaxing the smooth muscles of the blood vessels in your body. This increases blood flow and reduces blood pressure to your body organs. It is
used to treat pulmonary hypertension (increased pressures in arteries supplying the lungs) and to manage Raynaud’s phenomenon and ulcers on the fingers and toes associated with scleroderma. Sildenafil is the most common type of 5
phosphodiesterase inhibitor prescribed. Others include tadalafil. Sildenafil is also used in other conditions such as erectile dysfunction.
What benefit can you expect from your treatment?
Sildenafil is a medicine used to treat pulmonary hypertension. Sildenafil lowers the blood pressure by relaxing the blood vessels in the lungs. You may notice improvement in breathlessness, palpitations and/or exercise tolerance within a few weeks of starting treatment with sildenafil although in some cases it can take longer.
Sildenafil may prevent ulcers or improve healing of ulcers on fingers and toes. Benefits of continuing sildenafil will be reviewed at each clinic appointment, and it is important to let your rheumatologist know of any new medicines or conditions at each visit.
Stopping Sildenafil
If you stop or delay your sildenafil treatment, your condition may get worse. Keep taking sildenafil, unless advised by your rheumatologist to stop or unless serious side effects occur.
If you stop sildenafil for any reason, you must contact your rheumatologist.
How will your condition be monitored?
Before starting the treatment of pulmonary hypertension, you may have to undergo testing in the form of an echocardiogram (ultrasound scan of the heart), a 6-minute walk test and right heart catheterisation. These may be repeated to monitor your condition. You will be assessed by your rheumatologist to decide if the treatment is working.
How is Sildenafil given?
Sildenafil is taken by mouth in tablet form swallowed whole with a glass of water. Do not crush, break or chew the tablet, unless advised to by your doctor or pharmacist. It can be taken with or without food.
What is the dosage?
The usual dose given to treat pulmonary hypertension is 20mg three times daily, however your rheumatologist may decide to give you higher doses.
Can other medicines be taken?
Sildenafil is usually given alongside other medicines to treat pulmonary hypertension. Some medicines if taken with sildenafil may cause serious side effects.
Are there any side effects?
You might experience side effects with your treatment. Tell your doctor if you notice any side effects that you think might be caused by sildenafil.
Most common side effects
Most commonly reported side effects are headache (1 in 10 people), dizziness/light headedness, facial flushing, blurred vision, stuffy nose, nausea.
Less common or rare side effects
Less commonly reported side effects include rash or allergic reaction causing swelling of eyes, lips or throat (1 in 100), vomiting, rapid heartbeat, low blood pressure, ringing in the ears, dry mouth, blood in the urine and nosebleed.
Rare, reported side effects (less than 1 in 1000) include stroke, heart attack, loss of vision or bleeding at back of eye, loss of hearing, sustained penile erection, fits or seizures, severe peeling and swelling of skin and eyes.
What precautions are necessary?
Precautions with other diseases
Do not take sildenafil if you have:
- angina (chest pain), severe heart or liver problem
- recently had a stroke or heart attack
- low blood pressure causing fainting
- rare inherited eye condition (such as retinitis pigmentosa)
- ever had vision loss due to a condition called non-arteritic anterior ischemic optic neuropathy.
- allergy to sildenafil
Precautions with other medicines
Do not take sildenafil if you are:
- Taking medicine called nitrates used to treat angina or amyl nitrite (“poppers”) as combination may lead to a dangerous fall in blood pressure or lead to an angina attack.
- Taking riociguat to treat pulmonary hypertension as the combination may cause low blood pressure.
- Talk to your doctor if you are taking a protease inhibitor (used to treat HIV) as the dose of sildenafil may need to be lowered, alpha-blockers used to treat high blood pressure or prostate enlargement may cause dizziness or light headedness.
Use with alcohol
You are advised not to drink excessive amounts of alcohol while taking sildenafil.
Driving and using machine
Sildenafil can cause dizziness and can affect vision. You should be careful before you drive or use machines when starting sildenafil.
Use in pregnancy and when breastfeeding
Any woman who is taking sildenafil to treat pulmonary hypertension and is planning pregnancy should speak to her treating specialist to discuss her medicine. While breastfeeding, very small amounts of sildenafil may pass into breastmilk, however it is unlikely to cause any side effects in babies. Speak to your specialist for further information.
How to store sildenafil
Store sildenafil in a cool dry place, away from reach of children. Do not store above 30°C.
Important things to remember
- While taking sildenafil, you must see your rheumatologist regularly to ensure the treatment is working and to minimise any possible side effects.
- If you are worried about any side effects, you should contact your rheumatologist as soon as possible.
- It is important to tell your doctor if you are prescribed other medicines such as nitrates or are being treated for chest pain as some medicines can interact with sildenafil to cause serious side effects.
This Information Sheet has been prepared using materials obtained from various sources which have been reviewed by the Australian Rheumatology Association (ARA). It contains general information only and does not contain a complete or definitive
statement of all possible uses, actions, precautions, side effects or interactions of the medicines referenced. This information is not intended as medical advice for individual conditions nor for making an individual assessment of the risks and benefits of taking a particular medicine. Decisions regarding the assessment and treatment of patients are the sole responsibility of the treating medical professional, exercising their own clinical judgment and taking into account all of the circumstances and the medical history of the individual patient.
ARA has used all reasonable endeavours to ensure the information on which this Information Sheet is based is accurate and up to date. However, the ARA accepts no responsibility or liability for the accuracy, currency, reliability and/or completeness
of the information contained in this Information Sheet. To the maximum extent permitted by law, the ARA expressly disclaims any liability for any injury, loss, harm or damage arising from or in connection with use of and reliance on the information contained in this Information Sheet.
This information sheet is copyright and may be reproduced in its entirety but may not be altered without prior written permission from the ARA.
Page updated March 2026