This includes medicines such as sildenafil, vardenafil, and tadalafil. These are
taken in pill form. The medicines work by increasing blood flow to the penis, which
can lead to a fuller erection. The most common side effects of these pills are
headache, facial flushing, and upset stomach. Less common side effects are bluish or
blurred vision and sensitivity to light. An eye exam may be advised before using
these medicines. They can also have serious interactions with some other medicines,
such as nitrates taken for chest pains. Men with heart problems should check with
their healthcare provider before using these medicines.