Sildenafil

What is Sildenafil for?

Sildenafil is used to treat erectile dysfunction, a condition where you are unable to get or keep an erection firm enough to have sexual intercourse. It works by relaxing the blood vessels in your penis, allowing blood to flow into your penis when you get sexually excited. This medicine will only help you to get an erection if you are sexually stimulated. Therefore it is taken on an as-needed basis.

Sildenafil is also used to treat high blood pressure in the blood vessels in the lungs (pulmonary arterial hypertension). Sildenafil works by relaxing and widening the blood vessels in the lungs, and ultimately lowering the blood pressure in the lungs. This should improve your symptoms such as breathlessness, and increase your ability to exercise. This medication has to be taken on a daily basis.

How should I take or use Sildenafil?

• This medication may be taken with or without food.

For erectile dysfunction

• Take this medication before sexual activity. It starts to work within 1 hour and is effective up to 4 hours before sexual activity.
• This medication should be taken before food, on an empty stomach. You may find that this medicine takes longer to start working if you take it with a high-fat meal (such as cheeseburger or fries).

For pulmonary arterial hypertension

• Do not stop taking your medication without checking with your healthcare professional as it may worsen your condition.
• This medication is usually started at a lower dose. Medication dosage will be adjusted based on your condition and your response to this medication will be monitored closely.

What should I do if I forget to take or use Sildenafil?

For erectile dysfunction 

• As this medication is taken on an as-needed basis, do not take more than once a day or the dose prescribed for you.

For pulmonary arterial hypertension

• Take the missed dose as soon as you remember. Skip the dose if it is too near to your next dose. Then take your next dose at the usual time. Do not take two doses to make up for the missed dose.
• Do not take more than the dose prescribed to you.

What precautions should I take when taking or using Sildenafil?

Inform your healthcare professional if:

• You are allergic to this medication or any of the other ingredients of this medication.
• You are taking medicines called Nitrates (such as sublingual nitroglycerin (also known as Glycerin Trinitrate or GTN), Isosorbide Mononitrate or Isosorbide Dinitrate). The combination of nitrates with sildenafil may lead to a dangerous fall in your blood pressure. Nitrates must be withheld at least 24 hours after the last dose of Sildenafil. Tell your doctor if you are taking any of these medicines which are often given for relief of angina (chest pain). If you are not certain, ask your healthcare professional.
• You are taking medicines called Alpha-1 Blockers (such as Tamsulosin, Terazosin, Prazosin, Alfuzosin), as the combination may further lower your blood pressure. In order to reduce the chances of these symptoms occurring, you should be on a regular daily dose of your Alpha-blocker before you start medications for erectile dysfunction.
• You recently had a stroke or a heart attack, low blood pressure or uncontrolled high blood pressure.
• You have severe heart, liver or kidney problem.
• You have certain rare inherited eye diseases (such as retinitis pigmentosa. A rare eye disease that affects the retina (the light sensitive layer of tissue in the back of the eye) where it changes how the retina responds to light slowly over time, ultimately causing loss of vision.
• You have a stomach ulcer or bleeding problem (blood unable to clot normally)
• You have sickle cell anaemia (an abnormality of red blood cells).
• You have a deformity of your penis.

Pulmonary arterial hypertension in pregnancy is considered a high risk pregnancy which is potentially life-threatening for both mother and baby. Female patients of childbearing age should take precautions to avoid pregnancy by seeking advice from gynaecologist for effective contraceptive methods. Talk to your cardiologist before trying for a baby as your heart condition will need to be assessed. If you suspect you may be pregnant, inform your cardiologist as soon as possible.

What food or medication should I avoid when I take or use Sildenafil?

Avoid taking grapefruit, or grapefruit juice as they may interact with your medication and increase the risk of side-effects.

Drinking alcohol can temporarily weaken your ability to get an erection and may increase the blood pressure lowering effects of the medication, which can be dangerous. To get the maximum benefit from your medication, it is advisable not to drink alcohol before taking this medication.

Inform your healthcare professional if you are taking or intend to take any other medication, supplements, traditional medications or herbal remedies.

What are some common side effects of Sildenafil?

• Facial flushing where the skin on your face feels hot
• Headache
• Giddiness due to lowered blood pressure
• Visual disturbances (including blurring of vision, blue tinge in vision)
• Indigestion or stomach pain
• Nosebleed

What are some rare but serious side effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following: 

• Swollen face/eyes/lips/tongue
• Difficulty in breathing
• Itchy skin rashes over your whole body

Priapism (an erection that will not go away) - If you have an erection that lasts more than 4 hours, get medical attention immediately at the emergency department. If it is not treated right away, priapism can permanently damage your penis.

Sudden vision loss in one or both eyes - Sudden vision loss in one or both eyes can be a sign of a serious eye problem called non-arteritic anterior ischemic optic neuropathy (NAION). 

Sudden hearing decrease or hearing loss - Some people may also have ringing in their ears (tinnitus) or dizziness.

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

How should I store Sildenafil?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

How do I throw away Sildenafil safely?

Pack this medication into a black trash bag and seal it tightly before throwing into the rubbish chute or bin.