Viagra Connect can cause side effects, and isn’t suitable for men with certain medical conditions, or who are taking certain medications.

You should speak to a clinician right away if you experience:

• chest pains
• loss of sight
• an erection that doesn’t subside after 4 hours
• an allergic reaction
• any skin reactions such as blistering, peeling and swelling, or fever
• seizures or fits
• any other side effects that concern you 

Very common (more than 1 in 10 users):
Headache.

Common (up to 1 in 10 users):
Indigestion, feeling sick, dizziness, blocked up nose, flushing in the face, hot flush, blurred vision, visual disturbance and colour tinge to vision.

Uncommon (up to 1 in 100 users):
Being sick, acid reflux (including heartburn), upper abdominal pain, arm and leg pain, skin rash, tiredness, feeling hot, nosebleed, eye irritation, bloodshot or red eyes, eye pain, seeing flashes of light, sensitivity to light, visual brightness, watery eyes, pounding heartbeat, rapid heartbeat, high blood pressure, low blood pressure, muscular pain, drowsiness, vertigo, ringing in the ears, blocked or stuffy sinuses, blood in urine, inflammation of the lining of the nose.

Rare (up to 1 in 1,000 users):
Dry nose, fainting, swelling inside the nose, irritability, sudden reduction or loss in hearing, sudden cardiac arrest, stroke, heart attack, pains in the chest, reduced blood flow to the brain, irregular heartbeat, tightness in the throat, numbness in the mouth, double vision, bleeding at the back of the eye, reduced sharpness of vision, swollen eye or eyelid, abnormal sensation in the eye, spots in your vision, dilated pupils, seeing halos around lights, discoloration of the whites of the eye, blood in semen, penile bleeding.

Don’t take Viagra Connect if you:

• are using nitrate medications (these are used for heart conditions like angina);
• take nitric oxide donors (sometimes known as ‘poppers’, such as amyl nitrate);
• are using Riociguat (used to treat high blood pressure in the lungs);
• are taking HIV medications such as Ritonavir;
• don’t have erectile dysfunction;
• have been advised by your doctor to refrain from sex because of a heart issue or a problem with your blood vessels;
• have a serious heart issue such as a recent heart attack or stroke;
• have a severe liver problem;
• experience low blood pressure;
• have ever had a serious loss of vision because of nerve damage in the eyes, or an inherited eye disease;
• have a deformed penis;
• are a woman;
• are under 18 years of age;
• are allergic to sildenafil or to any of the other ingredients in Viagra Connect

It’s very important to let your prescriber know before taking Viagra Connect if you have:

• any heart problems or experience any breathing difficulties with light or moderate activity;
• a stomach ulcer or a bleeding disorder (such as haemophilia);
• ever had an erection that persisted for more than 4 hours;
• been previously diagnosed with mild to moderate liver disease, or serious kidney problems;
• been taking medicines to treat fungal infections and antibiotics;
• been taking heartburn treatment;
• been using other treatments for erectile dysfunction;
• been taking alpha blockers to treat urinary issues or high blood pressure;
• an intolerance to certain sugars, such as lactose.