Vilitra 40 mg should only be used under medical supervision. It should not be taken with nitrate medications or by individuals with serious heart conditions, as it can cause a dangerous drop in blood pressure. Because 40 mg is a stronger dose, the risk of side effects is higher. These may include headache, flushing, dizziness, nasal congestion, indigestion, or temporary vision changes. In some cases, these side effects can reduce overall comfort during sexual activity.