Cialis can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Cialis. These lists don’t include all possible side effects.
For more information on the possible side effects of Cialis, talk with your doctor or pharmacist. They can give you tips on how to deal with any side effects that may be bothersome.
Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you would like to report to the FDA a side effect you’ve had with Cialis, you can do so through MedWatch.
Mild side effects
Mild side effects of Cialis can include:*
Most of these side effects may go away within a few days or a couple of weeks. But if they become more severe or don’t go away, talk with your doctor or pharmacist.
* This is a partial list of mild side effects from Cialis. To learn about other mild side effects, talk with your doctor or pharmacist, or see Cialis’s Patient Package Insert.
Serious side effects
Serious side effects from Cialis aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.
Serious side effects and their symptoms can include:
- Change in hearing. Symptoms can include:
Other serious side effects, explained in more detail below in “Side effect details,” include:
Side effect details
You may wonder how often certain side effects occur with this drug† Here’s some detail on certain side effects this drug may cause.
As with most drugs, some people can have an allergic reaction after taking Cialis. Allergic reactions did occur in clinical trials of Cialis, but it wasn’t reported how many people had them. The allergic reactions included a serious rash and skin conditions such as Stevens-Johnson syndrome (a life threatening rash that causes painful blisters).
Symptoms of a mild allergic reaction can include:
- skin rash
A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:
- swelling under your skin, typically in your eyelids, lips, hands, or feet
- swelling of your tongue, mouth, or throat
- trouble breathing
Call your doctor right away if you have a severe allergic reaction to Cialis. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.
Headache is a common side effect that may occur with Cialis. In clinical trials, depending on the condition being treated:
- between 3% and 15% of people who took Cialis had headaches
- between 2.3% and 5% of people who took a placebo (treatment with no active drug) had headaches
If you have headaches that are bothersome to you while using Cialis, talk with your doctor. They may be able to recommend ways to help ease this side effect.
Changes in blood pressure
Changes in blood pressure are a possible side effect of taking Cialis. Low blood pressure occurs most often while taking this medication. But high blood pressure can occur as well.
low blood pressure
Clinical trials looked at blood pressure in people who took 20 mg of Cialis or a placebo. Blood pressure decreased by an average of 1.6/0.8 mm Hg more in the Cialis group than in the placebo group.
A decrease in blood pressure may be more likely if you’re taking Cialis along with other medications that can also lower blood pressure.
Symptoms of low blood pressure can include:
If you have these symptoms while taking Cialis, tell your doctor right away. They’ll help determine what’s causing the low blood pressure and the best way to treat it.
High blood pressure
Although rare, Cialis may also increase your blood pressure. This was a side effect that was reported only in people who took Cialis once a day for erectile dysfunction (ED). In this trial, depending on the condition being treated:
- between 1% and 3% of people who took the medication had high blood pressure
- no one who took a placebo had high blood pressure
If you have any symptoms of high blood pressure, such as headaches or chest pain, tell your doctor right away. They’ll help determine what’s causing the increase in blood pressure and the best way to treat it.
Back pain is a common side effect with Cialis. In clinical trials, depending on the condition being treated, back pain was reported in:
- 2% to 6% of people who took Cialis
- 1% to 3% of people who took a placebo
Back pain usually occurs between 12 and 24 hours after taking Cialis. Usually, back pain goes away within 2 days of taking your dose.
While taking Cialis, if you have back pain that’s bothersome to you or doesn’t go away, talk with your doctor. They may be able to recommend ways to help ease this side effect. Your doctor may also do more testing to see what’s causing your back pain.
Heartburn is a common side effect of Cialis. In clinical trials, depending on the condition being treated, heartburn occurred in:
- 1% to 10% of people who took Cialis
- 0.2% to 2% of people who took a placebo
If you have heartburn that’s bothersome to you while taking Cialis, talk with your doctor. They may be able to recommend ways to treat this side effect.
It’s possible to get a prolonged erection that lasts more than 4 hours while taking Cialis. It wasn’t reported how many people had a prolonged erection in clinical trials.
This side effect can lead to priapism, which is a painful erection lasting longer than 4 hours. It’s considered an emergency because it can cause permanent damage to your penis, such as being unable to have erections at all.
If you have an erection that lasts longer than 4 hours while using Cialis, see a doctor or go to the hospital right away. The prolonged erection should be treated as soon as possible so that it doesn’t cause lasting damage.
Loss of vision
Very rarely, Cialis may cause a loss of vision in either one eye or both eyes. It’s not known how many people had a loss of vision in clinical trials. Also, it’s not known if Cialis was the cause of vision loss or if other factors play a role.
While taking Cialis, if you have any changes in vision, such as decreased vision or loss of vision, tell your doctor right away. They’ll help determine what’s causing the vision change and how to best treat it.
How to avoid Cialis side effects
The best way to take Cialis is to use it exactly as your doctor directs, either once a day at the same time each day or only as needed. You shouldn’t take any other medications to treat erectile dysfunction (ED) while you’re using Cialis, unless your doctor says that it’s OK. And you should never take Cialis more than once a day.
It’s also important to avoid drinking too much alcohol while you’re using Cialis. (See the “Cialis and alcohol” section below to learn more.)
In addition, be sure to talk with your doctor or pharmacist about any other medications that you’re taking. They’ll be able to determine if the drugs may interact with Cialis and if that may lead to an increased risk of side effects. If you have any questions about the best way to avoid specific side effects from Cialis, talk with your doctor.