Sildenafil is used to treat pulmonary arterial hypertension (high blood pressure in the blood vessels leading to the lungs).
This medicine may be used to treat other conditions as decided by your doctor.
Take Sildenafil exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.
You may take this medicine with or without food. It is best to avoid taking this medicine with a high-fat meal. Try to take it at the same time each day.
Sildenafil is available as a conventional tablet or oral suspension.
If you are taking the oral suspension, shake the bottle well before you take the medicine to ensure that the liquid is evenly mixed. Use the measuring spoon or cup provided to measure your dose.
Sildenafil must be taken regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it unless instructed by the doctor.
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.
DO NOT double a dose under any circumstances.
If you often forget to take your medicine, let your doctor and pharmacist know.
Alert your doctor if you have the following conditions:
- recent heart attack or stroke
- low blood pressure
- known serious eye problems that run in your family e.g. retinitis pigmentosa (rare inherited eye disease causing a slow loss of vision)
- vision loss due to a condition known as non-arteritic anterior ischaemic optic neuropathy (lack of blood flow to the nerve at the back of the eye that connects to the brain)
- severe liver disease
as Sildenafil may not be suitable for you.
Do not take Sildenafil with medicines used to treat chest pain, fungal infection, HIV infection, and other medicine for pulmonary arterial hypertension. Please see the section "Can I take this with other medicines?" below for more information.
Inform your doctor if you have the following conditions:
- deformed penis shape
- blood disease e.g. leukaemia (cancer of the blood), sickle cell anaemia (a blood disorder that changes the shape of red blood cells from round flexible discs into stiff and sticky sickle or crescent moon cells which can slow or block blood flow)
- uncontrolled high blood pressure
- heart problems e.g. aortic stenosis (narrowing of the heart valves), abnormally thick heart muscle that results in blockage of blood flow
- active peptic ulcer (open sores in the lining of the stomach, small intestine, or lower food pipe)
- bleeding problems
- pulmonary veno-occlusive disease (a rare disease characterised by a blockage in the blood vessels of the lungs)
- mild to moderate liver disease
- kidney disease
Let your doctor know if you are pregnant or breastfeeding.
Be sure to check with your doctor or pharmacist before giving Sildenafil to the elderly. Elderly people may be more sensitive to the side effects.
Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly. Your blood pressure may fall to unsafe levels without you noticing it. Monitor your blood pressure regularly during treatment.
Sildenafil may cause dizziness or visual disturbances. If affected, do not drive or take part in any activity in which you need to be alert.
Other side effects include any of the following: headache, nausea, vomiting, stomach pain, indigestion, muscle pain, back pain, tiredness, flushing, and blocked nose or sinuses.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
- sudden chest pain, irregular heartbeat, shortness of breath
- sudden decrease or loss of hearing which may be accompanied by dizziness or ringing in the ears
- sudden loss of vision in one or both eyes
- painful or prolonged erection (erection lasting for 4 hours or more)
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Do not take Sildenafil with the following medicines:
- medicines for chest pain e.g. nicorandil, isosorbide dinitrate, glyceryl trinitrate
- riociguat (other medicine used to treat pulmonary arterial hypertension)
- medicines to treat fungal infection e.g. itraconazole, ketoconazole
- ritonavir (medicine for HIV infection)
Inform your doctor and pharmacist if you are taking any of these medicines:
- medicines for high blood pressure e.g. amlodipine, doxazosin
- erythromycin (certain antibiotic)
- rifampicin (medicine to treat TB, a lung infection known as tuberculosis)
- cimetidine (medicine that reduces stomach acid production)
This list does not include all medicines that may interact with Sildenafil.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements, and medicines that you buy without a prescription.
Avoid alcohol.
Avoid excessive consumption of grapefruit or grapefruit juice (more than 1 litre a day).
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.