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Cialis Overdose: How Much Is Too Much Cialis?

Katelyn Hagerty

Reviewed by Katelyn Hagerty, FNP

Written by Our Editorial Team

Published 06/13/2021

Updated 10/14/2023

Dealing with erectile dysfunction often means a lot of added frustration, and we’re not just talking about the kind in your bedroom. From the “big picture” health issues to the planning, there are a lot of ways that ED impacts your life. And on top of it all, you have to worry about medication safety.

If you’ve been prescribed an ED medication like tadalafil (brand name Cialis®), you know there are rules — you’ve got to take this stuff as directed for it to work. But what happens if you play fast and loose with the recommendations and take a little extra in hopes of giving your partner a little “extra” later?

Below, we’ve explained why this is a bad idea. We’ve covered how Cialis works and why you can overdose, as well as what the consequences are. So, before you take a second pill, read up on what could go wrong.

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Tadalafil is commonly prescribed by healthcare professionals to treat ED, benign prostatic hyperplasia (BPH) and pulmonary arterial hypertension, a type of high blood pressure in the lungs.

Like many ED drugs, tadalafil is in a class of medications called phosphodiesterase type 5 enzyme inhibitors (or PDE5 inhibitors). It works by increasing blood flow to the blood vessels of your penis, and elsewhere. When paired with sexual stimulation (you know, foreplay), it can help you get hard enough for the kind of sexual activity you want.

Depending on how you take it, Cialis can treat ED for up to 36 hours, which is where its reputation as a “weekend ED med” comes from. 

If you’re using Cialis as prescribed, it is a safe medication for most people. Like with many medications, here are some side effects of Cialis, most of which are mild and temporary.

But a healthcare provider is going to warn you that this FDA-approved medication isn’t safe if you start screwing around. And we’ve got to admit, they’re right: taking any ED medication incorrectly can raise your risk of those adverse effects — and make them more severe.

Calling it an “overdose” isn’t exactly the right terminology, but upping your dosage will increase your risk of both the mild and serious side effects.

And those problems can be a lot worse than just a missed opportunity for lovemaking.  

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Common, mild side effects of Cialis include:

  • Indigestion

  • Headache

  • Back pain

  • Muscle pain

  • Flushing 

  • Congestion

  • Pain in limbs

It’s important to understand that side effects can largely be dose-dependent, meaning that taking a very large dose of tadalafil will make side effects comparably worse. Said another way, a Cialis “overdose” is going to make the medication’s normal side effects worse. 

Taking too much Cialis also increases your risk of experiencing not just worse versions of the mild side effects, but also more severe adverse effects. These may include:

  • Difficulty breathing or swallowing

  • Blurred vision

  • Chest pain

  • Dizziness

  • Sudden decrease in blood pressure

  • Skin peeling or blistering

  • Sudden loss of hearing and/or loss of vision

  • Hives or rash

  • Swelling

  • Heart failure

  • Painful erection (priapism)

If you develop any of these side effects — mild or severe — seek medical help ASAP so that a healthcare professional can advise you on what to do.

Oh, one more thing: you don’t actually have to use Cialis improperly to experience some of the effects of “overdose,” which could include a stroke or heart attack. While these are very rare, they can happen even with normal doses of Cialis.

Because other medications and substances can increase the effects of tadalafil, you could see similar side effects from drug interactions with medications such as:

  • Nitrates like nitroglycerin or nitrite supplements

  • Alpha-blockers 

  • Over-the-counter ED supplements

  • Other prescription drugs for ED like Levitra® (vardenafil), Stendra® (avanafil) or Viagra® (sildenafil)

  • Angina medications like isosorbide

Some foods,  most notably grapefruit juice, can also increase the effects of tadalafil.

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Your healthcare provider will tell you how much Cialis to take. Typically, they will prescribe it either for as-needed or daily dose usage.

Daily Cialis is prescribed at either 2.5mg or 5mg and is meant to be taken every day at the same time, instead of as needed.

When prescribed for use as needed, there are three common dosages of Cialis that your healthcare provider may recommend.

  • 5mg: This lower dose is suggested if the normal 10mg starting dose produces too many side effects. 

  • 10mg: The FDA recommends this as the starting dose when trying tadalafil for the first time. Research has found that a majority of men with ED who used tadalafil at a 10mg dose were able to have penetrative sex with their partner.

  • 20mg: This is the maximum dosage prescribed for ED and is usually what’s suggested if 10mg isn’t effective.

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There are many reasons not to take Cialis the wrong way. Aside from the risk of allergic reaction or an uncomfortable (and erect) phone call with poison control, you should always take medications the way healthcare professionals recommend, pharmacies advise and experts direct.

In summary, here’s the hard fact list:

  • It is not safe to take more than your prescribed dosage of Cialis, and a larger dose won’t make you last longer in bed anyway. 

  • Tadalafil overdose can lead to serious side effects and death. For example, if you have cardiovascular health conditions, you could stop your heart by taking too much of this medication.

  • If your prescribed dosage of tadalafil isn’t working, your doctor will look into other things that may be causing your ED, like lifestyle and psychological factors, as well as a number of health issues.

Now that you know you shouldn’t take extra Cialis, you may be wondering if there are other ways it can help you perform. If you are, check out our guide to how to get the maximum effect from Cialis.

If you want to explore options, we also offer erectile dysfunction treatments like those mentioned above, and like our convenient hard mints chewable ED meds.

Do the right thing for your health: ask questions, get advice and take your medications seriously (and as prescribed).

5 Sources

  1. HIGHLIGHTS OF PRESCRIBING INFORMATION : CIALIS (tadalafil) tablets, for oral use. U.S. Food and Drug Administration. https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf.
  2. Sooriyamoorthy T, Leslie SW. Erectile Dysfunction. [Updated 2023 May 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK562253/.
  3. Frajese, G. V., Pozzi, F., & Frajese, G. (2006). Tadalafil in the treatment of erectile dysfunction; an overview of the clinical evidence. Clinical interventions in aging, 1(4), 439–449. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2699638/.
  4. Silberman M, Stormont G, Leslie SW, et al. Priapism. [Updated 2023 May 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459178/.
  5. Dhaliwal A, Gupta M. PDE5 Inhibitors. [Updated 2023 Apr 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK549843/.
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