What side effects can this medication cause? If it is not treated right away, priapism can permanently damage your penis sudden vision loss in one or both eyes. Yes, ED pills can cause side effects. If approved, the provider will issue a prescription. Psychological factors like stress, depression, or anxiety can also contribute. Some people may also have ringing in their ears tinnitus or dizziness. This medicine has been approved in the United States to treat premenopausal females who have low sexual desire. · Viagra comes as an oral tablet that contains the active drug sildenafil. Sildenafil is also available in generic form. Viagra is classified as a phosphodiesterase type 5 (PDE5) inhibitor. If you have these symptoms, stop taking VIAGRA and contact a doctor right away. have or have had heart problems such as a heart attack, irregular heartbeat, angina, chest pain, narrowing of the aortic valve, or heart failure. have had heart surgery within the last 6 months. have pulmonary hypertension. have had a stroke. Viagra (sildenafil): As the first FDA-approved PDE5 inhibitor for ED, sildenafil is taken