Silcap is used to treat erectile dysfunction, also known as impotence, in men. This is when a man cannot get, or keep, a hard erection during sexual activity.

Active ingredients: Sildenafil (as citrate)

Form: Capsule

Available in 2 strengths: 25mg & 50mg capsule

  • Pack 25mg [4, 8 & 12] AUST R 291996
  • Pack 50mg [4, 8 & 12] AUST R 291999

Also contains: Lactose. See CMI for further information.

Suitable for: Men 18 years and older who have difficulty getting and/or keeping an erection hard enough for sex.

Prescription Only Medicine

What is sildenafil?

Silcap, containing the active ingredient sildenafil citrate is a medicine used to treat Erectile Dysfunction (ED) in men.

It works by relaxing the blood vessels in your penis when you are sexually excited. This allows blood to flow into your penis, allowing you to get an erection in the natural way. Silcap will work only if you are sexually excited. It does not cure ED or increase your sex drive. Silcap is not for use in women.

How does it work

Silcap contains the active ingredient sildenafil, which belongs to a class of medicines called phosphodiesterase type 5 inhibitors. It works by relaxing the blood vessels in your penis when you are sexually excited, allowing blood flow to your penis, allowing you to get an erection hard enough for sex. The amount of time Silcap take to start working varies from person to person, but it normally takes within 30-60 minutes. It should only be taken when you need it. Silcap works only when you are sexually stimulated.

How to take

Your doctor will decide the correct dose for you depending on your condition and response. This can be 25mg a day, 50mg a day or up to a maximum of 100mg a day (two 50mg capsules). Do not take more than one dose of Silcap a day.


Silcap (sildenafil citrate) is a prescription medicine used to treat erectile dysfunction (ED) in men.

Consumer Medicine Info:

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You must not take Silcap if you are taking nitrates or nitrite medications. It may lead to a severe drop in your blood pressure, which may be difficult to treat. Because sexual activity may place a strain on your heart, your doctor will need to check whether you are fit enough to take Silcap.

Do not take Silcap if you are taking guanylate cyclase stimulators (GCS), such as Adempas (riociguat). GCS is a type of medicine used to treat high blood pressure in the blood vessels in the lungs caused by blood clots in the lungs (chronic thromboembolic pulmonary hypertension, CTEPH) or narrowing of the vessels that carry blood from the heart to the lungs (pulmonary arterial hypertension or PAH).

Do not take Silcap if the packaging is torn or shows signs of tampering, or does not look quite right even if the wafers may look alright.

Do not take Silcap if the expiry date on the pack has passed. If it has expired or is damaged, return it to your pharmacist for disposal.

Do not take Silcap if you have an allergy to sildenafil or similar medicines or any of the ingredients listed at the end of this leaflet. An allergic reaction can include:

  • Hives, itching or skin rash
  • Swelling of the face, lips or tongue which may lead to difficulty swallowing or breathing

Do not take Silcap if you:

  • Have heart or blood vessel problems that make sexual intercourse inadvisable
  • Have suffered a heart attack or stroke in the last 6 months
  • Have severe liver problems
  • Have blood pressure that is unusually high or low or is not effectively treated
  • Have loss of vision in one or both eyes from an eye disease called non-arteritic anterior ischaemic optic neuropathy (NAION)
  • Have an eye disease called retinitis pigmentosa

Before you start to take it

Tell your doctor if you:

  • Have any allergies to any other medicines or any other substances such as foods, preservatives or dyes.
  • Have any other heart or blood vessel problems.
  • Have previously had sudden loss of eyesight in one or both eyes.
  • Have any of the following medical conditions:
    • Diabetes, especially if you also have eye problems
    • Kidney or liver problems
    • Leukaemia (cancer of the blood cells)
    • Multiple myeloma (a cancer of the bone marrow)
    • Any disease or deformity of your penis
    • Any bleeding disorder such as haemophilia
    • Stomach ulcer
    • A disease of the blood called sickle cell anaemia
    • Colour vision problems
    • Previously experienced sudden decrease or loss of hearing
  • Are taking or using any other treatment for impotence.
  • Are taking any medicines to treat high blood pressure in the vessels of the lungs (pulmonary arterial hypertension). including Tracleer (bosentan) or Revatio which also contains sildenafil.

Tell your doctor if you have any other medical conditions. If you have not told your doctor or pharmacist about any of the above, tell him/her before you start taking Silcap.

Taking other medications

Tell your doctor or pharmacist if you are taking any other medicines, including medicines you buy without a prescription from a pharmacy, supermarket or health food shop. 

Do not take Silcap if you are taking or using nitrate medicines for angina. 

Do not take Silcap if you are taking guanylate cyclase stimulators (GCS), such as Adempas (riociguat). 

Some medicines and Silcap may interfere with each other. These include:

  • Cimetidine, a medicine used to treat ulcers
  • Some medicines used to treat fungal infections including ketoconazole and itraconazole
  • Some antibiotics including erythromycin and rifampicin
  • Some protease inhibitors such as ritonavir and saquinavir for the treatment of HIV infection
  • Medicines called alpha-blockers. These are used to treat high blood pressure or prostate problems
  • Tracleer (bosentan), a medicine used to treat high blood pressure in the vessels of the lungs.

You may need different amounts of your medicine or you may need to take different medicines. Your doctor or pharmacist can tell you what to do if you are taking any of these medicines. They also have a more complete list of medicines to be careful with or avoid while taking Silcap. Ask your doctor or pharmacist, if you are not sure if you are taking any of these medicines.

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking Silcap.

While Silcap helps most people, it can cause some unwanted side effects in a few people. All medicines have side effects. If unwanted effects occur, most are likely to be minor and temporary. However, some may be serious and need medical attention. 

Do not be alarmed by this list of possible side effects. You may not get any of them. 

Tell your doctor or pharmacist if you notice any of the following and they worry you:

  • Headache
  • Dizziness
  • Flushing
  • Hot flushes
  • Indigestion
  • Nasal congestion
  • Sinus congestion
  • Redness in your mouth or tongue
  • Swelling of your nose
  • Dry mouth or dry throat
  • Dry nose
  • Dry eye
  • Tightness in your throat
  • Diarrhoea
  • Heart burn
  • Rash
  • Feeling hot or irritable

Tell your doctor as soon as possible if you notice any of the following:

  • Unusual heart beat
  • Urinary tract infection (stinging or burning urine, more frequent need to pass urine)
  • Blood in the urine
  • Persistent headache or fainting
  • Bleeding from the nose
  • Pain or tingling in your hands, toes or feet
  • Decreased sensitivity or numbness in your mouth
  • Irritation or feeling of having something in the eye
  • Swollen or puffy eye(s)
  • Fatigue, pain in or around the eyes
  • "Red eye" due to swollen blood vessels in the white part of the eye and in the eyelids

If any of the following happen, tell your doctor immediately or go to Accident and Emergency at your nearest hospital:

  • Signs of allergy such as shortness of breath, wheezing or difficulty breathing; swelling of the face, lips, tongue or other parts
  • Chest pain
  • Increased heart rate
  • Sudden decrease or loss of hearing
  • Seizures, fits or convulsions
  • Your erection is increased, painful or persists for longer than usual. If your erection continues for four hours, or sooner if there is pain, you should seek medical attention urgently
  • Rarely men have lost eyesight sometime after taking drugs to treat erectile dysfunction (known as impotence). If you lose eyesight in one or both eyes or experience changes in vision such as blurring, a blue colour to your vision or a greater awareness of light, seek medical attention urgently
  • Changes to your normal vision such as:Red or yellow colour tinges to your vision or colourless objects appear coloured
  • You see a halo around lights, sparks or lights when your eyes are closed

This is not a complete list of all possible side effects. Others may occur in some people and there may be side effects not yet known. If you notice any other symptoms that worry you, check with your doctor. 

Ask your doctor or pharmacist if you don't understand anything in this list.

Get into the mood. You will not get an erection just by taking Silcap. You must be sexually stimulated for it to work.

Take your time. Silcap usually starts to work within 30-60 minutes. Take your dose of Silcap about one hour before you intend to have sex.

Eat smart before you start. Silcap can be taken with or without food. If you take Silcap after a heavy or high-fat meal, it may take a little longer to start working.