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A Complete Guide to Cialis® (Tadalafil) Side Effects

Katelyn Hagerty

Medically reviewed by Katelyn Hagerty, FNP

Written by Our Editorial Team

Last updated 12/1/2022

Cialis®, which contains the active ingredient tadalafil, is a popular medication that’s prescribed as a treatment for erectile dysfunction, or ED.

Available for use as needed and as a daily treatment for erectile dysfunction, Cialis can provide lasting relief from erectile dysfunction symptoms, allowing you to enjoy more satisfying, fulfilling sex without having to worry about losing your erection.

Like other medications for the treatment of erectile dysfunction, Cialis — and its generic version, tadalafil — can cause adverse effects. 

Most side effects of Cialis are mild and transient. However, there are a few side effects that you should be aware of before starting treatment, as well as drug interactions that could occur when Cialis is used with other medications. 

Below, we’ve explained what Cialis is, as well as how it works as a treatment for ED. We’ve also listed common and uncommon side effects of Cialis to help you understand what to expect while using this ED medication. 

What Is Cialis Used For?

Before we go into detail on specific side effects, let’s quickly go over the basics of what Cialis is and how it works as a treatment for ED. 

Cialis® is an FDA-approved medication for erectile dysfunction. It’s currently the longest-lasting erectile dysfunction medication that’s available, providing effects that can last for up to 36 hours per dose. 

Viagra®, in comparison, typically lasts around four hours. The long-lasting effects of Cialis have earned it the nickname of the “weekend” ED pill. 

Like other erectile dysfunction treatments, Cialis belongs to a class of medications referred to as phosphodiesterase type 5 inhibitors, or PDE5 inhibitors

Cialis and other PDE5 inhibitors work by increasing blood flow to the erectile tissue that’s found inside your penis. When you’re sexually aroused, blood flows into this tissue more easily, which can make it easier to get and maintain an erection.

Cialis is a safe and effective medication for most men, and it’s widely used in the United States and around the world by men of all ages and backgrounds.

So, what is Cialis used for, aside from ED? Tadalafil, the active ingredient in Cialis, is also used to treat a condition called benign prostatic hyperplasia, or BPH. 

Additionally, tadalafil is also sold under the brand name Adcirca® as a medication for managing pulmonary arterial hypertension (PAH), a form of high blood pressure that can affect the arteries in the lungs.

What Are The Side Effects of Cialis?

Like other prescription drugs, Cialis can cause side effects. Most of the side effects of Cialis are mild and temporary, meaning they’ll fade away as Cialis exits your body. 

However, there are also several more severe potential side effects of Cialis that, although highly uncommon, are important to know about. 

Cialis and tadalafil contain the same active ingredient and work in the same way. As such, both medications have the potential to cause the same side effects and drug interactions. 

Below, we’ve listed common and uncommon potential side effects of Cialis and tadalafil, as well as information on how frequently these side effects occur and what you can do to minimize your risk of being affected. 

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The Most Common Side Effects of Cialis

Cialis has several common side effects, many of which also occur with other drugs used to treat erectile dysfunction. 

This means that if you experience a certain side effect while using Cialis, you may also develop the same issue with medications like sildenafil (generic Viagra), vardenafil (Levitra®) or avanafil (Stendra®).

Headaches

Headaches are a common side effect of all ED medications, including Cialis. In fact, headaches are among the most frequently reported adverse effects of tadalafil, making an appearance in all clinical trials of this medication. 

Cialis is a vasodilator, which means it improves blood flow throughout your body, including to the erectile tissue of your penis. By causing your blood vessels to dilate, Cialis can put pressure on nerves in your head, increasing your risk of developing a headache.

Most of the time, Cialis headaches are fairly mild. They typically become less intense over time, although Cialis’s long half-life means that a dull headache might continue for several hours after you use this medication.

According to a 2008 review of studies on tadalafil, 15 percent of men who use this medication at its highest recommended dose (20mg) experience headaches.

Headaches can still be common for those who take a lower 10mg dose of Cialis, affecting about 12 percent of men.

If you’re prone to headaches after taking Cialis, our guide to treating headaches from ED drugs may help. It lists several effective techniques for managing this side effect, from adjusting your dosage to using over-the-counter pain relief medication.

Dyspepsia (Indigestion and/or Heartburn)

Cialis can cause a range of digestive side effects, including indigestion. This is one of the most common side effects of tadalafil, affecting about eight percent of users at 10mg dosage and 10 percent of users at a higher 20mg dose.

Indigestion is a common side effect of all ED medications, not just Cialis. It occurs as a result of the effects of PDE5 inhibitors on smooth muscle tissue in your body. 

When you take Cialis, it could cause your lower esophageal sphincter (the part of your body that controls the flow of your stomach contents) to relax. This may lead to heartburn as stomach acid travels from your stomach upward into your esophagus.

For example, researchers have found that sildenafil, the active ingredient in the similar ED drug Viagra, produces a noticeable decrease in lower esophageal sphincter pressure.

If you develop acid reflux, an upset stomach or other digestive issues after taking Cialis, making some small changes to your habits can make this side effect easier to deal with. 

Most of the time, you should be able to manage any stomach upset by drinking more water and using over-the-counter antacid medication. 

If you experience this side effect often, you may want to consider discussing your Cialis dosage with your healthcare provider. They may adjust your dosage or suggest other changes that you can make to your use of this medication to reduce the severity of this side effect.

Back Pain

Cialis can cause back pain. Approximately three to six percent of Cialis users develop back pain, and the discomfort tends to occur around 12 to 24 hours after taking the medication.

Many people who experience back pain from Cialis report that it usually fades on its own within 48 hours.

Mild to moderate back pain from Cialis can be treated using over-the-counter pain relief. If you experience severe back pain after using Cialis, it’s important to talk to your healthcare provider about adjusting your dosage or switching to another ED medication.

Muscle Aches

Like Viagra and other ED medications, a small percentage of men who use Cialis experience myalgia, or pain that involves your muscles, ligaments, tendons and/or fascia.

In clinical trials of Cialis, approximately one to four percent of men reported muscle pain as an adverse effect, with this side effect more common in men prescribed tadalafil at a dosage of 10 or 20mg. 

Muscle aches from Cialis or other ED medications are typically mild and tend to only last while the medication is active in your body.

If you experience pain or discomfort after taking Cialis that’s more than just a faint annoyance, it’s important to talk about this with your healthcare provider.

Facial Flushing

Because Cialis causes your blood vessels to dilate, it might temporarily give you a red, flushed appearance, especially around your nose, cheeks, chin and forehead. This side effect, which is referred to as flushing, can also occur elsewhere on your face and body. 

Around three percent of men who use Cialis experience facial flushing. This side effect typically occurs with moderate and high doses. Like with other side effects of Cialis, it usually fades as your body metabolizes the medication over the course of several hours.

Since facial flushing is a common ED medication side effect, switching to another drug such as Viagra or Levitra might not help the issue. If you’re prone to facial flushing, it’s best to discuss it with your healthcare provider.

Nasal Congestion

Like other ED medications, Cialis can cause nasal congestion. This side effect occurs in two to three percent of men who take Cialis and can occur with all dosages, from 5mg to 20mg taken as needed before sex.

Nasal congestion may occur due to tadalafil’s effects on blood vessels. When you use tadalafil, it may affect nitric oxide levels inside your nasal cavity, giving you a stuffy nose that could make breathing through your nostrils difficult.

As with many other Cialis side effects, nasal congestion tends to fade on its own as your body processes the medication.

While nasal congestion is a common side effect of all ED medications, switching from Cialis to shorter-acting drugs like Viagra or Levitra may make this side effect less long-lasting, as these medications remain active in your body for shorter periods of time.

Nasopharyngitis (Common Cold Symptoms)

Some men who use Cialis to treat ED report developing cold-like symptoms, or nasopharyngitis, after taking the medication.

As the common cold is a viral infection, it’s unlikely that Cialis is directly responsible for causing people to become sick. However, this medication’s effects on the soft tissue inside the nose and throat may cause some users to experience symptoms similar to those of a cold.

If you experience cold symptoms after taking Cialis, it could be due to the effects of the drug on your body’s soft tissue. 

If these symptoms bother you, consider talking to your healthcare provider about adjusting your dosage or switching to a shorter-acting erectile dysfunction treatment.

Dizziness

Dizziness is a fairly uncommon side effect of Cialis. A small percentage of men who use Cialis report feeling dizzy and light-headed after taking this medication.

Other ED medications, such as Viagra and Levitra, may cause dizziness due to their effects on nitric oxide levels in the body. 

If you feel dizzy after taking Cialis and don’t notice this side effect improving over time, it’s best to talk to your healthcare provider. They may suggest adjusting your dosage or switching to an alternative ED treatment. 

Visual Disturbances

Several ED medications, including Cialis, are associated with visual disturbances such as color vision changes and blurred vision. 

Although these side effects are temporary, they have the potential to affect your vision while the medication is active within your body. Because Cialis has a longer half-life than other ED drugs, this means that you could have some level of blurred vision or color issues for several hours.

If you experience blurred vision, difficulty seeing colors or other visual disturbances after taking Cialis, it’s important to talk to your healthcare provider. 

These side effects could be treatable by adjusting your dosage or using a shorter-acting erectile dysfunction medication.

Reduced Blood Pressure

Does Cialis lower blood pressure? Like other PDE5 inhibitors, Cialis can produce a mild drop in your blood pressure levels. 

In healthy men without heart disease or other cardiovascular health issues, this is not a problem and doesn’t cause any health issues.

In fact, lowered blood pressure is a common side effect of all FDA-approved erectile dysfunction medications. It’s typically caused by the dilating effects of these medications on blood vessels — an effect that can improve blood flow throughout certain areas of your body.

This drop in blood pressure can be potentially dangerous if you take certain medications to treat hypertension, such as nitrates.

If you have any cardiovascular health issues, make sure you tell your healthcare provider before you discuss CIalis or any other treatment for ED.

Pain in Limbs

In clinical trials, one to three percent of men who used Cialis reported experiencing pain in their limbs. This side effect was most common in men who were prescribed Cialis at a dosage of 10 or 20mg per day.

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Daily Cialis Side Effects

Cialis is available as a medication for use as needed and as a daily-use medication for treating erectile dysfunction.

In general, the adverse effects of daily-use Cialis are identical to those of Cialis when it’s taken as needed before sex. 

However, because daily-use Cialis is prescribed at a lower dosage, some side effects appear to be less common.

For example, in clinical trials, 11 to 15 percent of men reported headaches from Cialis at a dose of five to 20mg. In comparison, only three to six percent of men who took Cialis every day at a dose of either 2.5mg or 5mg reported headaches.

Other side effects, such as dyspepsia and back pain, were also reported less frequently by men prescribed Cialis for daily use. 

Our guide to daily Cialis provides more information about the advantages and disadvantages of using Cialis every day to treat ED.

Less Common, More Serious Cialis Side Effects

Cialis can cause serious side effects, although these are rare. Serious adverse effects of Cialis include priapism (a painful erection that may last for four hours or longer), optic nerve damage, hearing issues and interactions with other prescription medications.

Priapism

Priapism is a prolonged, often painful erection that lasts for four hours or longer. It’s a serious medical emergency that requires immediate attention to avoid damaging the erectile tissue in your penis.

Although it’s possible to experience a prolonged erection after using Cialis, this is an extremely uncommon side effect. 

Considering millions of men use ED medications such as Cialis, it’s easy to see that the chance of experiencing priapism after using this type of medication is very low.

If you get a persistent and/or painful erection after using Cialis, it’s important to seek emergency medical care immediately. A healthcare professional can safely and effectively treat priapism to prevent any damage to your penile tissue. 

Optic Nerve Damage

Cialis is one of several ED medications associated with optic nerve damage, which may cause or contribute to vision loss. Like priapism, this is an extremely rare side effect that only affects a tiny percentage of Cialis users.

The condition that Cialis is linked to is called nonarteritic anterior ischemic optic neuropathy, or NAION. It can develop when the blood supply to the optic nerve is reduced, potentially producing a reduction of the visual field.

Although exact data isn’t available, tadalafil was listed as one of several PDE5 inhibitors linked to rare reports of NAION in a study of sildenafil (Viagra) and optic nerve damage.

NAION appears to occur primarily in people with a pre-existing risk factor for eye damage, such as a small cup-to-disc ratio.

Hearing Issues

According to the FDA, several ED medications, including Cialis, have been linked to a decrease in hearing sensitivity or hearing loss in postmarketing reports.

Like priapism and damage to the optic nerve, cases of sudden hearing loss caused by Cialis are very uncommon. Evidence suggests that some of the reported cases of hearing loss associated with Cialis may be linked to underlying medical conditions.

If you take Cialis to treat ED and notice any changes in your hearing, it’s best to stop taking this medication and consult your healthcare provider as soon as you can. 

Allergic Reaction to Cialis

Allergic reactions can occur with all medications, and Cialis is no exception. It’s possible to have an allergic reaction to the tadalafil that’s used in this medication, or to other, inactive ingredients that are used as part of the manufacturing process.

Common symptoms of an allergic reaction may include hives, rash, swelling that affects the lips, throat and tongue, and difficulty breathing or swallowing.

If you experience any of the above symptoms or other possible signs of an allergic reaction after taking Cialis, it's important to seek emergency medical help.

Other Rare Side Effects

Other uncommon side effects of Cialis include chest pain, ringing that affects your ears and skin issues, such as blistering and/or skin peeling.

Make sure to inform your healthcare provider if you develop these or other side effects after you use Cialis or other medications for ED.

Cialis Drug Interactions

As a PDE5 inhibitor, Cialis can interact with other medications, including medications prescribed to treat hypertension (high blood pressure), fungal infections, cardiovascular health issues such as coronary artery disease (CAD) and heart failure, as well as other medical conditions.

Interaction With Blood Pressure Medications

Tadalafil can interact with nitrates used to treat hypertension, angina and other heart conditions, causing abnormally low blood pressure that can lead to loss of consciousness, heart attack and even cardiac arrest (sudden death).

If you take nitrates like nitroglycerin, isosorbide dinitrate, isosorbide mononitrate or amyl nitrate to treat hypertension (high blood pressure) or angina (heart-related chest pain), you should not take Cialis.

In fact, you should not take any PDE5 inhibitors, such as sildenafil (Viagra), vardenafil (Levitra) or avanafil (Stendra), if you’re prescribed a nitrate medication. 

All of these drugs interact with nitrates to cause a significant drop in blood pressure. In addition to nitrates used to treat cardiovascular conditions, ED medications can also interact with certain recreational drugs that contain nitrates, such as amyl nitrate “poppers.”

Do not use Cialis if you use any nitrate medications or recreational drugs, as this could result in severe side effects. 

If you have heart disease, high blood pressure or any other cardiovascular health issue, inform your healthcare provider before using Cialis or any other medication to treat ED.

Interaction With Antifungal Medications

Cialis can interact with some oral antifungal medications used to treat issues such as ringworm and fungal nail infections. These medications, which inhibit the CYP3A4 enzyme, may increase your exposure to the effects of Cialis.

Oral antifungal medications include itraconazole and ketoconazole, among others. Some other medications that affect CYP3A4, such as the antibiotic erythromycin, and ingredients that affect CYP3A4, such as grapefruit or grapefruit juice, may also interact with Cialis.

You can read more about the relationship between grapefruit products and Cialis in our guide to Cialis and grapefruit interactions.

If you're prescribed these medications, your healthcare professional may adjust your dosage of Cialis to reduce your risk of developing side effects. 

The FDA suggests taking Cialis at a maximum as-needed dosage of 10mg no more than once per 72 hours — or a daily dosage of 2.5mg — if you’re prescribed any other medication that inhibits CYP3A4.

Other Medications That May Interact With Cialis

Other medications may also interact with Cialis, including the following:

  • Ritonavir. This antiretroviral medication inhibits CYP3A4 and may increase the effects of Cialis in your body.

  • Alpha-blockers. Alpha-blockers can cause a drop in blood pressure when taken with Cialis. These medications are frequently prescribed to manage high blood pressure, benign prostatic hyperplasia (enlarged prostate) and other conditions.

    Common alpha-blockers include Flomax® (tamsulosin HCl), Hytrin® (terazosin HCl), Cardura® (doxazosin mesylate), Uroxatral® (alfuzosin HCl), Jalyn® (dutasteride and tamsulosin HCl), Minipress® (prazosin HCl) and Rapaflo® (silodosin).

  • Other PDE5 inhibitors. Other PDE5 inhibitors, such as sildenafil (Viagra), vardenafil (Levitra) and avanafil (Stendra) should not be used with Cialis.

How to Avoid Cialis Side Effects

Cialis comes in tablet form, making it convenient to use as a treatment for ED. Although some online vendors advertise liquid versions of Cialis, these products are unregulated in the United States. 

Currently, Cialis is available in two forms. The first is an as-needed version that’s prescribed for use before sexual activity, while the other is a daily-use pill.

If you're prescribed Cialis for use ‘as needed,’ you should take this medication around one hour before you plan to have sex. 

Most men find that a normal dose of Cialis starts working within 30 to 60 minutes, and it can last for up to about 36 hours. This is significantly longer than other ED medications, such as Viagra (sildenafil), vardenafil (Levitra) or avanafil (Stendra).

Cialis can be used with or without food. It may take some time for you to find the right dosage of Cialis and time to use this medication for optimal sexual function. 

Although there’s no simple, one-size-fits-all way to completely eliminate side effects from Cialis, there are several things that you can do to reduce your side effect risk.

Limit Your Alcohol Consumption

Drinking alcohol with Cialis can increase your risk of experiencing side effects. Alcohol can also negatively impact your sexual performance and level of sexual stimulation.

Try to limit your alcohol consumption while taking Cialis. The best way to do this is to avoid any alcohol consumption. However, if you typically drink alcohol while out on dates or just as part of your normal lifestyle, limiting your consumption to one to two small servings can also help. 

Only Use Cialis as Prescribed

Most potential side effects of Cialis become more common at higher doses. Make sure to only use the dosage of Cialis that’s prescribed to you, even if you feel that it isn’t fully effective as a treatment for ED. 

If you find it hard to get or maintain an erection after using Cialis, don’t adjust your dosage on your own. Instead, let your healthcare provider know about your concerns. They may increase your dosage or suggest other changes you can make to improve your erectile function.

Don’t Take Cialis More Than Once Per Day

Cialis is a long-lasting ED medication that’s not intended for use more than one time per day. A single dose of Cialis should produce a noticeable improvement in your erections that continues for up to 36 hours.

If you don’t notice any improvements after taking Cialis, do not take a second tablet. Instead, let your healthcare provider know. They may suggest adjusting your dosage or switching to another ED medication. 

Cialis and Benign Prostatic Hyperplasia (BPH)

Although Cialis is widely known as a treatment for erectile dysfunction, it's also approved by the FDA for use as a treatment for benign prostatic hyperplasia (BPH, or enlarged prostate).

As a treatment for BPH, Cialis is typically taken daily. The potential side effects and interactions of Cialis are the same whether Cialis is used for ED or BPH, making it important to be aware of these effects before using this medication.

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The Bottom Line on the Side Effects of Cialis

It’s quite normal to experience one or several minor side effects from Cialis. However, serious side effects are uncommon. 

If you’re prescribed Cialis for erectile dysfunction or benign prostatic hyperplasia and notice a concerning or problematic side effect, it’s important to talk to your healthcare provider as soon as you can.

They may recommend adjusting your Cialis dosage or making certain changes to the way you take this medication. 

In some cases, your provider may recommend switching to another ED drug, such as sildenafil (the active ingredient in Viagra), vardenafil (Levitra) or avanafil (Stendra).

These medications are shorter-acting than Cialis, meaning any side effects you experience may fade away in a shorter amount of time. 

We offer several FDA-approved ED medications online, following a consultation with a licensed healthcare provider who will determine if a prescription is appropriate.

You can learn more about the causes of and treatments for ED in our complete guide to erectile dysfunction.

9 Sources

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references.

  1. Dhaliwal, A. & Gupta, M. (2022, May 20). PDE5 Inhibitors. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK549843/
  2. Tadalafil. (2022, February 15). Retrieved from https://medlineplus.gov/druginfo/meds/a604008.html
  3. Coward, R.M. & Carson, C.C. (2008, December). Tadalafil in the treatment of erectile dysfunction. Therapeutics and Clinical Risk Management. 4 (6), 1315-1330. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2643112/
  4. CIALIS- tadalafil tablet, film coated. (2017, May). Retrieved from https://www.accessdata.fda.gov/spl/data/05dbd8b6-1b9d-436a-a67c-8a16713f753f/05dbd8b6-1b9d-436a-a67c-8a16713f753f.xml
  5. Bortolotti, M., et al. (2001, November). Effects of sildenafil on esophageal motility of normal subjects. Digestive Diseases and Sciences. 46 (11), 2301-2306. Retrieved from https://pubmed.ncbi.nlm.nih.gov/11713926/
  6. Questions and Answers for Cialis (tadalafil). (2015, August 13). Retrieved from https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/questions-and-answers-cialis-tadalafil
  7. Stockman, A., et al. (2007, June). The effect of sildenafil citrate (Viagra) on visual sensitivity. Journal of Vision. 7 (8), 4. Retrieved from https://pubmed.ncbi.nlm.nih.gov/17685811/
  8. Too much of a good thing: The 4-hour erection. (2008, September 11). Retrieved from https://www.nbcnews.com/healthmain/too-much-good-thing-4-hour-erection-1C9926694
  9. Gorkin, L., Hvidsten, K., Sobel, R.E. & Siegel, R. (2006, April). Sildenafil citrate use and the incidence of nonarteritic anterior ischemic optic neuropathy. International Journal of Clinical Practice. 60 (4), 500-503. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1448698/

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.