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A Complete Guide to Cialis (Tadalafil) Side Effects

Katelyn Hagerty FNP

Medically reviewed by Kristin Hall, FNP

Written by Our Editorial Team

Last updated 5/26/2021

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

Below, we’ve explained what Cialis is, as well as the side effects you may experience if you’re prescribed this medication.

What Is Cialis Used For?

Cialis® is an FDA-approved medication for erectile dysfunction. It’s the longest-lasting erectile dysfunction medication available, providing effects that can last for up to 36 hours. (Viagra®, in comparison, typically lasts around four hours.)

Like other erectile dysfunction treatments, Cialis is a phosphodiesterase type 5 inhibitor, or PDE5 inhibitor. 

It works by increasing blood flow to the erectile tissue of your penis. When you’re sexually aroused, this makes 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.

Now, what is Cialis used for, aside from ED? Cialis is also commonly used to treat BPH. 

Additionally, Tadalafil, the active ingredient in Cialis, is also sold under the brand name Adcirca® and is used to treat Pulmonary Arterial Hypertension (PAH) at a different dosage.

What Are The Side Effects of Cialis?

Like other prescription drugs, Cialis can cause side effects. Most of the side effects of Cialis are minor, although it’s possible for PDE5 inhibitors to sometimes cause a variety of more severe side effects in certain cases.

The brand name Cialis is used to refer to tadalafil, its active ingredient, and both Cialis and generic tadalafil work in exactly the same way. 

Both medications can cause the same side effects and drug interactions.

Below, we’ve listed common (and uncommon) side effects of tadalafil, the active ingredient in Cialis, along with information on potential frequency and what you can do to help minimize potential side effects.

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 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, Cialis headaches are among the most frequently reported side effects of tadalafil (the active ingredient in Cialis), making an appearance in almost all trials of the medication.

Cialis is a vasodilator–which means it improves blood flow throughout your body–including to the erectile tissue of your penis. 

And 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 can mean that a dull headache might last for several hours after taking the medication.

According to a 2008 review of studies on tadalafil (the active ingredient in Cialis), 15 percent of men who use it 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.

If you’re prone to headaches after taking Cialis, our guide to treating headaches from ED drugs may help. 

It lists several techniques for managing this side effect, from adjusting your dose to using over-the-counter pain relief medications.

Indigestion and Heartburn

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

Indigestion and heartburn can be a common side effect of all ED medications, and not just Cialis. It occurs as a result of Cialis’s action on smooth muscle tissue in your body. 

When you take Cialis, it can cause your lower esophageal sphincter (the part of your body that controls the flow of your stomach contents) to relax. 

This can lead to heartburn as stomach acid travels from your stomach upward into your esophagus.

Most of the time, this side effect can be managed by increasing water consumption and using over-the-counter antacids. 

If you experience this side effect often, consider discussing adjusting your Cialis dosage with your healthcare provider.

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Back Pain

Cialis can cause back pain, and while most side effects also occur with Viagra and Levitra, back pain appears to be significantly more common with Cialis use than with other ED medications.

Approximately five 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 get back pain from Cialis report that it typically 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 muscle aches. 

These aches are usually mild and tend to last as long as Cialis is active in your bloodstream.

About three to four percent of men who use Cialis report muscle aches as a side effect. If you experience pain after using 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 blood vessels to dilate, it can temporarily give you a red, flushed appearance–especially around your nose, cheeks, chin and forehead, although it can also occur elsewhere on the face and body.

About three percent of men who use Cialis experience facial flushing. This side effect typically occurs with moderate and high doses, and as 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 like Viagra or Levitra may 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 use Cialis and can occur at both 10mg and 20mg dosages.

Nasal congestion can sometimes result from tadalafil’s effects on blood vessels. After you take tadalafil, it can affect nitric oxide levels in your nasal passage. 

This can give you a blocked or stuffy-feeling nose that makes 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)

Some men who use Cialis report experiencing 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, the drug’s effects on the soft tissue of 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 may 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 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. 

As with many other common tadalafil side effects, this may be reduced by adjusting your dosage of the medication.

Visual Disturbances

Several ED medications, including Cialis, are linked to visual disturbances such as blurred vision and impaired color.

These side effects may occur due to the effects of the medication on the PDE-6 enzyme, which is present inside the retina.

Although these side effects are temporary, they have the potential to affect your vision while the medication is active in your body. 

And 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 using Cialis, 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

Like other PDE5 inhibitors, Cialis can cause a mild drop in blood pressure. 

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

In fact, lowered blood pressure is a common side effect of all FDA-approved erectile dysfunction medications, and relates to the drugs’ effects on relaxing smooth muscle tissue and blood vessel dilation. 

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

Between one and three percent of people who used Cialis in clinical trials reported pain in the limbs.

Note that the statistics provided above are for Cialis used as needed at a dosage of either 5mg, 10mg or 20mg. When taken daily at a lower dosage, many of the common side effects of Cialis occur less frequently.

Like other PDE5 inhibitors, Cialis may cause a mild drop in your blood pressure levels if used with other common medications. It is important to inform your healthcare provider of all the medications and supplements you take regularly.

Less Common, More Serious Side Effects of Cialis

Cialis can cause some serious side effects, although these are rare. Serious side effects of Cialis include priapism(a painful erection that can last for four hours or longer), and interactions with some medications used to treat hypertension and angina.

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 erectile tissue.

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

There were only 93 reported cases of priapism from all ED medications in the entire year of 2007, of which only 16 involved men who had taken Cialis.

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, painful erection after using Cialis, seek emergency medical care immediately. 

A qualified health professional can safely and effectively treat priapism to prevent any damage to penile tissue.

Optic Nerve Damage

Cialis is one of several ED medications linked to potential optic nerve damage, potentially causing vision loss. Like priapism, this is a 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 occurs when blood supply to the optic nerve is reduced,  potentially causing a reduction of the visual field.

Although exact data isn’t available, tadalafil is 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

Cialis, as well as similar ED medications such as Viagra and Levitra, may have the potential to cause hearing loss.

According to the FDA, hearing loss–and in some cases accompanied by tinnitus and dizziness–can be related to “ the intake of PDE5 inhibitors.”

Like priapism and damage to the optic nerve, cases of hearing loss caused by Cialis are highly uncommon. 

If you use Cialis to treat ED and notice any effects on your hearing, the FDA recommends that you stop taking this medication and seek immediate medical attention.

Allergic Reaction to Cialis

Like other medications, it's possible to have an allergic reaction to tadalafil or other included ingredients.

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

  • Chest pain

  • Ringing in your ears

  • Skin peeling or blistering

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 and nitrites 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)t.

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 use any PDE5 inhibitors, such as sildenafil (Viagra), vardenafil (Levitra) or avanafil (Stendra). 

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 some recreational drugs that contain nitrates, such as amyl nitrate “poppers.”

Do not use Cialis if you use any nitrate medications. If you have heart disease, hypertension or any other cardiovascular condition, inform your healthcare provider before using Cialis or any other medication to treat erectile dysfunction.

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

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 recommends taking Cialis at a maximum as-needed dosage of 10mg not more than once every 72 hours, or a daily dosage of 2.5mg, while using medications that inhibit 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, or α-blockers, can cause a drop in blood pressure when used with Cialis. These medications are often prescribed to treat high blood pressure or benign prostatic hyperplasia (enlarged prostate). 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 Properly Use Cialis

Cialis comes in tablet form, making it convenient to treat erectile dysfunction. Some online merchants may advertise liquid versions of Cialis, however, they are unregulated in the United States.

Currently, Cialis is available in two different versions. The first is an as-needed version designed to be taken before sexual activity, and the other is a daily pill .

If you're prescribed Cialis for use ‘as needed,’ you should take this medication shortly 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, which is significantly longer than other ED medications, such as Viagra (sildenafil), vardenafil (Levitra) or avanafil (Stendra).

Cialis can be taken with or without food, and for best results, make sure to:

Limit Alcohol Consumption

As mentioned above, drinking alcohol increases your risk of experiencing Cialis side effects. Alcohol can also negatively impact your sexual performance and level of sexual stimulation.

Try to limit alcohol consumption while using Cialis, either by avoiding drinks that contain alcohol or stopping after one to two drinks.

Correct Timing

Take Cialis at the same time each day especially if you're prescribed Cialis for daily use. This helps you maintain a steady level of Cialis in your bloodstream throughout the day.

Avoid Taking Cialis More Than Once Per Day

Cialis is a long-lasting ED medication that’s not intended for use more than once per day. 

A single dose of Cialis should produce a noticeable improvement in your erections that lasts for up to 36 hours.

Talk to Your Healthcare Provider About Your Dosage

If you don't see an improvement in your erections and sexual performance after taking Cialis, it's important to talk to your healthcare provider. 

You may need to adjust your dosage for optimal results.

Cialis and Benign Prostatic Hyperplasia (BPH)

Although Cialis is widely known as a treatment for erectile dysfunction, it's also FDA approved 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 it's used for ED or BPH, making it important to be aware of these effects before using this medication.

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Learn More About Cialis and Erectile Dysfunction

Although it’s quite normal to experience one or several minor side effects from Cialis, 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.

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

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

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.

6 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. CIALIS (tadalafil) tablets, for oral use. (2011, October). Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/021368s20s21lbl.pdf
  2. Carson, C.C., et al. (2004, June). The efficacy and safety of tadalafil: an update. BJU International. 93 (9), 1276-81. Retrieved from https://pubmed.ncbi.nlm.nih.gov/15180622/
  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. 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
  5. Mapes, D. (2008, September 11). Too much of a good thing: The 4-hour erection. Retrieved from https://www.nbcnews.com/healthmain/too-much-good-thing-4-hour-erection-1C9926694
  6. 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.

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