Sildenafil for pulmonary hypertension

Key points about sildenafil

  • Sildenafil is a medicine used to treat pulmonary hypertension.
  • Find out how to take it safely and possible side effects. 
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Sildenafil is used to treat pulmonary hypertension (high blood pressure in the blood vessels that supply your lungs). It works by relaxing and widening the blood vessels in your lungs, which improves blood flow and reduces pulmonary blood pressure to your heart and improves its function. 

Note: Sildenafil is also used for erection problems. Read more about sildenafil for erection problems.

In Aotearoa New Zealand sildenafil is available as tablets (25mg, 50mg and 100mg). It can also be made into a syrup by your pharmacy, but they will need time to prepare this.

  • The usual adult dose for pulmonary hypertension is 25mg, 3 times daily. 
  • Always take your sildenafil exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much sildenafil to take, how often to take it and any special instructions.

  • Swallow the tablet whole with a full glass of water. Don't take it with grapefruit juice.
  • You can take sildenafil with or without food.
  • Try to space the doses evenly throughout the day. This could be first thing in the morning, mid-afternoon and at bedtime. Ideally these times should be at least 6 to 8 hours apart.
  • Keep taking sildenafil regularly. Don't stop taking sildenafil without talking to your doctor first.

For information on how to give sildenafil to children, see sildenafil information for parents and carers.(external link)

Here are some things to know when you're taking sildenafil. Other things may be important as well, so ask your healthcare provider what you should know about.

Taking other medicines and supplements

Sildenafil can interact with some medicines, herbal supplements and rongoā Māori, so check with your doctor or pharmacist before starting sildenafil and before starting any new products.

Pregnancy and breastfeeding

If you are pregnant or plan to become pregnant, talk to your doctor. Tell your doctor if you are breastfeeding.

Like all medicines, sildenafil can cause side effects, but not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Blocked nose
  • Sensation of redness and warmth or burning of the face (called facial flushing)
  • This is quite common when you first start taking sildenafil. 
  • These effects usually go away with time. 
  • Tell your doctor if they bother you.
  • Headache
  • Dizziness
  • Muscle aches and pains
  • Tell your doctor if they bother you.
  • If you feel dizzy, don't drive or operate heavy machinery.
  • Indigestion 
  • Dry mouth
  • Cough
  • Night sweats
  • Tell your doctor if these bother you.
  • Chest pain 
  • Rash or swelling of the face
  • Sudden problems with your eyesight such as loss of vision, in one or both eyes
  • Sudden loss of hearing  
  • Tell your doctor immediately or ring Healthline 0800 611 116.
For more information on side effects, see the Medsafe consumer information leaflets below.

Did you know that you can report a medicine side effect to the Centre for Adverse Reactions Monitoring (CARM)? Report a side effect to a product.(external link)

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Credits: Healthify He Puna Waiora editorial team. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

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