• Tadalafil (Cialis) is available in generic and brand versions in several doses as an oral tablet.
  • You can take Cialis as needed or once a day, depending on the dose and how it’s prescribed.
  • Cialis takes from 30 minutes to 2 hours to take effect. It can last up to 36 hours.
  • Cialis is a PDE5 inhibitor medication approved for use for erectile dysfunction (ED) and benign prostatic hyperplasia.
  • Don’t take Cialis with nitrate class medications. Doing so can cause a dangerous drop in blood pressure.
  • If an erection lasts more than 4 hours, seek immediate medical attention.

Cialis is a brand of tadalafil, one of the most popular medications to treat erectile dysfunction (ED). It was first approved in 2003.

Cialis is popular because it offers dosing flexibility, works well, and is convenient to take.

Let’s take a quick look at how Cialis works, then get into how long it takes to act, how long it lasts, and things you can do that affect results.

Taking the medication properly will help you get the maximum effect.

How common is ED?

ED is a common condition. It affects between 5 and 20 percent of men globally.

While there are many causes of ED, studies show the risk of ED increases with certain health issues, including:

Certain surgeries, such as prostate gland removal (radical prostatectomy) or surgeries in the lower pelvic or rectal area, may also cause ED.

Healthline

Cialis is a phosphodiesterase type 5 (PDE5) inhibitor. It works for ED by relaxing smooth muscle in the blood vessels of the penis, therefore increasing blood flow.

PDE5 inhibitors only work in the presence of nitric oxide, which is naturally released during sexual arousal. PDE5 inhibitor medications work in 60 to 70 percent of people with ED.

Tadalafil is available in several doses in tablet form: 2.5 milligrams (mg), 5 mg, 10 mg, and 20 mg. Depending on the dose for ED, you can use it as needed before sexual activity, or take it once a day.

Let’s look at those two options, since dosing has a big effect on how it works.

Cialis offers two dosing options, which increase flexibility and allows greater choice. Your health, lifestyle, and the dosing of Cialis can affect how well the medication works.

A 2017 review of 16 studies comparing sildenafil (Viagra) and tadalafil found they’re equally effective for ED and have similar safety profiles.

But the review found tadalafil is preferred over sildenafil by users and their partners, and increases confidence.

Two important benefits of Cialis include dosing flexibility and long half-life. Tadalafil is the longest lasting PDE5 inhibitor medication for ED.

As-needed dosing

The usual starting dose for as-needed Cialis is 10 mg. It’s adjusted upward or downward depending on how you react to the medication.

Don’t take more than one dose per day to avoid the risk of a prolonged, painful erection (priapism), drop in blood pressure, or other serious side effects.

Take one tablet 30 minutes before sexual activity as directed by your doctor.

Daily dosing

The usual starting dose for once-daily Cialis is 2.5 mg. Your doctor might increase the dose to 5 mg based on how you react to the medication.

Take one tablet as prescribed at the same time each day. Many people who take Cialis prefer this dosing because it provides flexibility for timing of sexual activity.

Cialis doesn’t work right away.

For the as-needed dose, plan to take Cialis at least 30 minutes before sexual activity, but bear in mind it may take as long as 2 hours to take effect.

Also, Cialis requires sexual stimulation to be effective, so arousal is an important part of the equation.

There are many considerations that affect how long it takes Cialis to take effect for ED. This includes factors such as:

  • other health conditions you may have
  • other medications you may take
  • your age
  • your diet
  • your dose of Cialis
Tip for use

Take the daily dose at the same time every day to ensure there’s a steady level of the medication in your system.

Since you don’t need to plan ahead for sexual activity, many men and their partners prefer this dosing regimen.

Cialis can last from 24 to 36 hours. In some cases, it can last as long as 72 hours.

This is one of the reasons Cialis has high patient satisfaction ratings in surveys compared to other PDE5 inhibitors: It allows more spontaneous sexual activity.

How long the medication lasts depends on:

  • the dose
  • what kind of dose (as needed versus daily)
  • your age
  • your liver and kidney function
  • other medications you may be taking
  • your health condition
  • your lifestyle and diet

Take as directed

For as-needed dosing, take Cialis at least 30 minutes or more before sexual activity.

If your prescription involves taking Cialis daily, take it at the same time each day. This maintains steady levels of Cialis in your body.

Take as part of a lifestyle with physical activity

Smoking, heavy drinking, unmanaged stress, and an unhealthy diet can affect ED as well as how Cialis works, potentially leading to more side effects.

A healthy diet, increasing physical activity, and quitting smoking are important for wellness, physical health, and can affect the severity of ED.

Strategies to reduce stress and support your relationship with your partner can also improve sexual performance and well-being.

Communicate and stay relaxed

Working with a psychiatrist, therapist, or sex therapist can help you navigate strategies for the mental and emotional side of intimacy.

Other ways to improve your sexual performance include managing stress, working through relationship concerns, and treating performance anxiety.

If you’re anxious, stressed, depressed, or nervous, Cialis may not work as well. It’s important to relax and be aroused for the medication to work best.

High fat foods

Avoid high fat foods or heavy meals before taking Cialis and before sexual activity. High fat foods can affect how well Cialis works. It may also take longer to work.

Nitrates and other medications

Some medications can interact with Cialis and change its effectiveness. They include:

Be sure to talk to your doctor or pharmacist about how to take all your medications to avoid interactions.

It’s important to avoid Cialis if you take chest pain (angina) and blood pressure medications in the nitrate category or alpha blocker drugs. They can lower your blood pressure to dangerous levels.

Alcoholic beverages

Use caution with alcohol consumption when taking Cialis. Too much alcohol can affect your ability to become aroused. It can also cause excessive low blood pressure, leading to headache, dizziness, and fainting.

Grapefruit and grapefruit juice

Avoid grapefruit with Cialis. It can increase the levels of the medication in the blood, causing increased side effects.

Age

In some people over 65 years old, Cialis may last longer because it takes more time for your body to process the medication. This affects how soon it leaves your body.

Poor kidney function can increase Cialis levels in your body, increasing side effects. Your doctor may adjust your dose in this case.

Heart and other conditions

If you’re over 65, have a heart condition, or liver- or kidney-related problems, your doctor may need to adjust your dose of Cialis and monitor how the medication works for you.

Fake Cialis

Avoid buying Cialis without a doctor’s prescription. PDE5 medications are some of the most common counterfeit medications sold online. They can cause serious health risks.

Take as prescribed

Take Cialis exactly as prescribed by your doctor. Don’t take extra doses or change your dosing schedule without talking with your doctor to avoid side effects.

Common side effects

The most common side effects of Cialis include:

  • back pain
  • diarrhea
  • flushing (redness of the face, neck, or chest)
  • headache
  • upset stomach
  • muscle aches

Serious side effects

Serious side effects of Cialis include:

  • priapism, a painful erection lasting longer than 4 hours, which can cause tissue damage
  • low blood pressure
  • changes in hearing and vision
When to get medical help

For more information on drug interactions or side effects of Cialis, talk to your doctor or pharmacist.

If you experience serious side effects, call 911 or your local emergency services.

ED is a common condition and can have many causes, including psychological and physiological reasons.

Risks of ED are higher with certain health conditions, so it’s important to openly talk with your doctor about your concerns. They can help you find the best treatment specific to your situation. This may include the need for ED medications.

Cialis is one of the most popular medications available for ED because it provides two types of dosing and lasts longer than other PDE5 inhibitor medications in this class, like sildenafil (Viagra).

There are several PDE5 inhibitor medications available, so discuss your needs and preferences with your doctor to select the medication best suited to you.

Remember, there are many causes for ED and many treatment options, including Cialis. Don’t be discouraged if Cialis doesn’t work the first time you try it. Your doctor can help adjust the dose or help you find other options to consider.