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Comparing Erectile Dysfunction Drugs

Tuesday 25 May 2021
Erectile Dysfunction
4 minute(s) read
Dr.Stanley Zaslau

Medically reviewed by

Dr Stanley Zaslau, MD

on 23 September 2022


Table of Contents


I. How ED Medications Work 

II. Differences in Longevity 

III. Differences in Strength 

IV. Differences in Side Effects 

V. What's the Consensus?


There are several drugs available such as Cialis, generic Viagra, and Levitra, that can improve erectile dysfunction (ED) symptoms, but what’s the difference between these medications? It is important to have a good understanding of ED before jumping into a treatment plan. Read on to learn more about Canadian Cialis as well as the different types of ED medications available.

How do Erectile Dysfunction Medications Work?

An erection is caused by the engorgement of the penis with blood. Under normal conditions, sexual stimulation leads to the production and release of nitric oxide in the penis. Nitric oxide activates an enzyme that causes the production of cyclic guanosine monophosphate (cGMP). This enzyme is responsible for controlling the amount of blood that the vessels deliver and remove from the penis.

a cartoon of someone with a backache

All ED medications are PDE5 inhibitors (phosphodiesterase). After ejaculation, PDE5 completes the erection process by breaking down a substance called cGMP (cyclic guanosine monophosphate). Once cGMP is broken down, the blood leaves the penis, and the erection subsides. PDE5 inhibitors prevent this breakdown process and keep the penis erect for longer. This is because the blood vessels in the penis remain dilated so blood can remain in the penis, prolonging the sexual experience for men.

Differences in Longevity

Some people may prefer Cialis over other ED medications because it can be taken daily, meaning a consistent concentration of tadalafil in the body so you are ready for sexual activity at any time. Generic Cialis also comes with as-needed options, which are stronger dosages to be taken at least 30 minutes before sex. As-needed Cialis reaches peak concentration and effect two hours after taking the medication but can last for up to 36 hours.

Viagra and Levitra do not remain in the bloodstream as long as Cialis and only last for about 4 to 6 hours. This is beneficial for some if a man only wants to take ED drugs on an as-needed basis for sexual intercourse. Sildenafil and vardenafil are rapidly absorbed, so it takes about an hour to reach the maximal concentration of these drugs.

Differences in Strength

As mentioned above, Cialis is available at lower strengths to allow for daily dosing. At Canada Pharmacy Depot, Cialis is available at 2.5 mg, 5 mg, 10 mg, and 20 mg dosage strengths. It is important to note that dosages of Cialis vary depending on a man’s health conditions. The dosage may need to be reduced if kidney or liver disease is present.

Viagra is available in 25 mg, 50 mg, and 100 mg tablets. Levitra comes in 5 mg, 10 mg, or 20 mg dosages. Based on your current medical problems as well as treatment goals, your doctor will determine which dosage strength is right for you.

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Side Effects of ED Drugs

Some possible side effects of Cialis can include:

  • Headache, back pain, nasal congestion, and flushing
  • A possible drop in blood pressure (hypotension), muscle or limb pain, or conjunctivitis
  • Hearing loss or painful erections lasting longer than four to six hours

Some side effects of Viagra can include:

  • Nausea
  • Dizziness
  • Rash
  • Urinary tract infections
  • Facial flushing
  • Headaches
  • Possible vision changes and color perception
  • Priapism (an erection that lasts more than 4 hours) [1]

a pile of multi-colored pills

Levitra is used when needed, and, like Viagra, it is advised not to take this medicine more than once a day. A man should allow 24 hours to pass between doses. It is important to pay attention to any side effects, including:

  • Painful erection that lasts longer than 4 hours
  • Heart attack symptoms (chest pain, nausea, sweating, pain in the jaw or shoulder, pain radiating to the left arm)
  • Stuffy nose
  • Upset stomach
  • Back pain
  • Flushing

Nitrate medications (nitroglycerin) should be avoided to prevent dangerous drug interactions. In general, Levitra has fewer side effects than Viagra. Vision changes are considered a common side effect of Viagra, but changes to color perception are only a rare side effect of Levitra. [2]

What's the Best ED Pill?

Every medication has its pros and cons. Once you speak to your doctor about ED and your current medical problems, they will help determine which drug is best. A physician will consider a man’s age, weight, and pre-existing health issues to determine the most effective erectile dysfunction drug. No matter what a man decides, Canada Pharmacy Depot is the place to buy Viagra and Cialis medications at a discounted cost.

When you use Canada Pharmacy Depot, you can save time and money through our online pharmacy. You will never have to go to a physical pharmacy again because we send all of your treatment medications directly to your door. Visit our site to learn more today.

The content in this article is intended for informational purposes only. This website does not provide medical advice. In all circumstances, you should always seek the advice of your physician and/or other qualified health professionals(s) for drug, medical condition, or treatment advice. The content provided on this website is not a substitute for professional medical advice, diagnosis or treatment.

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