Tadalafil vs. Sildenafil vs. Vardenafil

Instructor: Alexandra Unfried

Alexandra earned her master's degree in nursing education and is currently a hospital supervisor/administrator.

Tadalafil, sildenafil, and vardenafil are all medications that help with erectile dysfunction. This lesson will address the uses, cautions, and side effects of each one, including their similarities and differences.

Which Medication is Best?

John is a sixty-year-old man who is having problems achieving an erection. He set an appointment to meet with his doctor to seek out treatment options. John has seen many different commercials on the television, but is confused as to which medication may work best for him. The doctor first goes over how erectile dysfunction medications work and contraindications to be cautious of.

Erectile Dysfunction Medications

Tadalafil, sildenafil, and vardenafil are erectile dysfunction medications. They work as vasodilators by relaxing the muscles in the penis, so blood is able to flow more efficiently in order to produce an erection. Vasodilators open the blood vessels. Sexual stimulation is required to get an erection, and should not occur on its own. There are also several contraindications:

  1. Nitrates for chest pain (causes a dangerous decrease in blood pressure)
  2. Alpha-blocker medications taken for blood pressure or prostate enlargement (decreases blood pressure)
  3. Grapefruit/Grapefruit juice (increases the amount of medication in the blood, which can cause an increase in side effects)

A doctor should be notified if an erection lasts more than four hours without sexual stimulation. This could indicate priapism, which occurs when blood is trapped in the penis. Priapism can cause permanent scarring or damage if left untreated.

John understands the uses and risks of taking medication for erectile dysfunction. He is not on any nitrates or medication for blood pressure, so he asks his doctor which medication is most recommended. The doctor discusses tadalafil, sildenafil, and vardenafil with John, to give him more insight.


Tadalafil is also known as Cialis. It comes in a pill form and should be taken 30-60 minutes before having sex. However, it can also be prescribed to be taken once each day. A larger dose of tadalafil is needed when taking it only for sex. A smaller dose is needed when taking it daily. Tadalafil is effective for up to 36 hours.


Sildenafil is also known as Viagra. It comes in a pill form and works best when taken 30-60 minutes before having sex. Sildenafil lasts for four to five hours.


Vardenafil is also known as Levitra. It comes in a pill form and should be taken 30-60 minutes before having sex. Vardenafil lasts for up to eight hours.

Tadalafil, Sildenafil, and Vardenafil all have similar side effects. Common side effects include:

  • Low blood pressure
  • Dizziness
  • Flushing
  • Back pain
  • Stuffy nose
  • Headaches
  • Nausea
  • Changes in vision
  • Priapism

Headache: a side effect of erectile dysfunction medications
Headache: a side effect of erectile dysfunction medications

John reviews each of the medications to compare them:

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