Scroll to top
Best CBD Company Reviews: Top CBD Oil Brands & Manufacturers [2022]

Does CBD Interact With Sildenafil (Viagra)?

Cannabidiol or CBD may prolong the effects of sildenafil (Viagra) — but is this combination safe? What are the risks?

Article By
Daily CBD , last updated on December 20, 2021

Sildenafil (Viagra) is used in the treatment of erectile dysfunction (ED). 

Cannabidiol (AKA CBD) is primarily used to manage chronic pain, anxiety, or insomnia — but it has many other health benefits as well. 

Some people report using CBD alongside sildenafil to boost its effects — helping to increase erectile function and eliminate concomitant issues like performance anxiety. 

Is this combination safe? What are the risks of taking CBD with Viagra (sildenafil)? 

Sildenafil tablets (illustration)

Does CBD Interact With Sildenafil (Viagra)?

Yes. CBD can interact with sildenafil (Viagra) and should be used with caution. 

The main concern with using CBD and Viagra is an increased risk of side effects. While uncommon, Viagra can lead to headaches, dizziness, indigestion, and a condition called priapism which involves painful and long-lasting erections. 

CBD may also prolong the effects of Viagra by slowing down the body’s ability to eliminate it. 

Let’s explore each type of interaction more closely. 

A) Slowed Elimination (Metabolic Inhibition)

Drug metabolism occurs in the body due to the effects of a group of enzymes from the P450 family. Metabolic inhibition occurs when two drugs need the same enzymes to get metabolized. Hence, they end up competing against each other for the said enzymes. This action could result in slowing down the metabolism of one or both drugs. 

Sildenafil is extensively metabolized by CYP450 enzymes, especially CYP3A4 (major route) and CYP2C9 (minor route). CBD also gets metabolized by these same enzymes. 

Because of this ability, if CBD and sildenafil are taken together, the plasma levels of sildenafil can rise in the body. This only becomes dangerous if Viagra is used continuously on a daily basis. Over time, concentrations of the drug can build up to dangerous levels. It’s important to allow enough time between doses for it to be cleared from the body. 

B) Increased Effect (Agonistic Interaction)

An agonistic interaction occurs when two or more items exhibit the same effect on the body. 

In the case of CBD and sildenafil, the shared effect focuses on blood vessel dilation. Both CBD and sildenafil cause the blood vessels to relax. This could lead to symptoms of excessive relaxation, which include dizziness, headaches, and priapism. 

Other Names For Sildenafil(Viagra)

Sildenafil is sold under many different names. All share the same risk and potential interactions.

Other names for sildenafil include:

  • Alsigra
  • Aryagra
  • Caverta
  • Edegra
  • Giagra
  • Medigra
  • Penegra
  • Revatio
  • Silagra
  • Vega
  • Vizarsin
  • Xcite
  • Zenegra

Similar Medications: CBD & Erectile Dysfunction Medications

CBD and erectile dysfunction medications (PDE5 inhibitors) all carry the same level of risk for interaction. Most ED medications work through the same mechanism and require metabolism by the same enzymes in the liver. 

Here’s a list of similar medications that share a similar level of risk when combined with CBD:

  • Tadalafil (Cialis)
  • Vardenafil (Levitra, Staxyn, and Vivanza)
  • Avanafil (Stendra)
  • Mirodenafil (Mvix)
  • Udenafil (Zydena)
Two CBD oil containers and a couple of hemp leaves over white background.

Is It Safe to Take CBD & Sildenafil (Viagra) Together?

The interaction between sildenafil and CBD is considered mild. 

However, because of the severity of one side effect in particular (priapism), it’s wise to speak to your doctor before taking CBD alongside your prescription Viagra. 

To further reduce your chances of experiencing interactions, it’s wise to separate the doses of each substance by about 2 hours. 

If you experience any problems or concerns, contact your physician immediately.

Is CBD A Viable Alternative to Sildenafil (Viagra)?

CBD is not considered a viable alternative to sildenafil.

Cannabidiol and other cannabinoids have been shown to improve ED in some individuals, but this effect relies more heavily on the effects of CBD for reducing anxiety conditions (such as performance anxiety). 

Sildenafil targets the blood vessels directly feeding blood flow to the penis. This effect is not found in studies exploring the effects of CBD. 

For people who may be experiencing mild forms of ED or could trace the cause of their ED to anxiety, CBD could be a safer alternative. However, people who experience ED as a result of mechanical dysfunctions are unlikely to find CBD even remotely as effective for managing symptoms as sildenafil. 

Related: The Best CBD Oil for Anxiety and Depression.

What is Sildenafil (Viagra)? 

Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor. Viagra is one of its brand names. It’s used in the treatment of erectile dysfunction and pulmonary hypertension

It is an FDA-approved drug and is sold as a prescription-only drug in most countries.  

Sildenafil (Viagra) Specs:

Drug Name  Sildenafil
Trade Names Viagra, Silagra, Alsigra, Aryagra, Caverta, Edegra, Giagra, Medigra, Penegra, Vega, Xcite, Zenegra, Revatio, Vizarsin
Classification  Phosphodiesterase 5 inhibitor
CYP Metabolism  CYP450 enzymes, especially CYP450 3A4(major route) and CYP2C9 (minor route)
Interaction With CBD Metabolic inhibitor, Agonistic
Risk of Interaction  Mild

What Does Sildenafil (Viagra) Do?

Sildenafil works by inhibiting phosphodiesterase 5 (PDE5). Its main action is to increase the blood flow to a flaccid penis. This ability causes it to get erect. Sildenafil does this by inhibiting an enzyme called phosphodiesterase type 5 (PDE5). PDE5 is commonly found in corpora cavernosa, vascular smooth muscles, visceral smooth muscles, and platelets. 

Originally developed as a potential blood pressure medication, sildenafil’s ability to cause erection in patients with erectile dysfunction was accidental but a very welcome one. This discovery caused it to become one of the most valuable methods to treat ED. 

Generally, in sexual intercourse, after an adequate amount of foreplay, there will be a release of nitric oxide (NO) from nerve terminals and endothelial cells. This action releases cyclic guanosine monophosphate (cGMP) too. 

The cGMP’s release causes the muscles of corpora cavernosa in the penis to relax and the blood vessels to get dilated. It leads to a rapid entry of blood into those vessels, causing the penis to engorge, grow large, and get erect. The penis stays so until the end of the intercourse and until after ejaculation occurs.  

The enzyme PDE5 prevents blood vessels in the penis from relaxing. It does this by causing the degradation of cGMP. In most ED patients, the blood vessels in the penis are also affected and lose their ability to relax properly or have some obstructions in them. 

Sildenafil inhibits PDE5, increases the level of cGMP in the corpus cavernosum, allows more blood to flow into the penis, and causes the penis to get erect long enough to have sex. 

However, sildenafil needs proper sexual stimulation to do its work. With a relaxed mind and good sexual stimulation, this drug may work even better. 

Apart from the presence of PDE5 in the corpus cavernosum of the penis, PDE5 is also present in the pulmonary vasculature. Hence, sildenafil can increase cGMP within pulmonary vascular smooth muscle cells and cause them to relax. In patients with pulmonary arterial hypertension, this can lead to vasodilation of the pulmonary vascular bed and systemic circulation. 

It is not recommended for use in women and children. Sildenafil does not cause dependence and addiction. This drug may show mild to dangerous interactions when combined with some medications. These include nitrates, antihypertensive medications, guanylate cyclase stimulators, antacids, CYP3A4 inhibitors, and CYP3A4 inducers. Sildenafil should not be used with these medications. 

Sildenafil is not recommended for consumption alongside alcohol of any form. It must be avoided in users with severe heart disease, hypersensitivity to sildenafil, priapism, severe renal and liver disease, stomach ulcers, retinitis pigmentosa, and blood disorders. 

Side Effects of Sildenafil (Viagra)

  • Headaches
  • Tingling sensation in the limbs and extremities
  • Hot flushes
  • Abdominal pain 
  • Bluish tinted vision
  • Loss of vision
  • Sensitivity to light
  • Nasal blockage
  • Back pain
  • Nausea
  • Abnormal vision
  • Skin rash
  • Dyspepsia
  • Diarrhea
  • Muscle pain
  • Prolonged and painful erection

Suggested Reading: What Are the Side Effects of CBD?

Viagra (sildenafil) tablets pack

Key Takeaways: Is it Safe to Take Sildenafil (Viagra) With CBD?

CBD can slow down the metabolism of sildenafil in the body — potentially causing it to remain active in the body for a longer duration. 

Additionally, CBD may potentiate some of the effects of Viagra, leading to a higher risk of side effects (especially dizziness and priapism). 

Always consult with your doctor before taking CBD if you’ve been given a prescription for Viagra or another version of sildenafil (the active ingredient in Viagra). 


  1. Carvalho, R. K., Andersen, M. L., & Mazaro‐Costa, R. (2020). The effects of cannabidiol on male reproductive system: A literature review. Journal of Applied Toxicology, 40(1), 132-150. 
  2. Pizzol, D., Demurtas, J., Stubbs, B., Soysal, P., Mason, C., Isik, A. T., … & Veronese, N. (2019). Relationship between cannabis use and erectile dysfunction: a systematic review and meta-analysis. American journal of men’s health, 13(6), 1557988319892464. 
  3. Blessing, E. M., Steenkamp, M. M., Manzanares, J., & Marmar, C. R. (2015). Cannabidiol as a potential treatment for anxiety disorders. Neurotherapeutics, 12(4), 825-836. 

Learn More About CBD-Drug Interactions

Learn More About CBD-Drug Interactions

Signup to our newsletter

Be the first to know about our newest arrivals and special offers!