How Does Cialis Work and What Are the Side Effects?

Published July 18th, 2022 by Chris Riley
Fact Checked by

It works by increasing blood flow to the penis, which helps you get and keep an erection.

Viagra and Cialis are similar medications; however, we will highlight the main differences between the two so you can make an informed decision with your doctor if you have erectile dysfunction.

Other topics we will also discuss in this article include delving into more detail about how Cialis works and the side effects that can occur.

We will also provide information on how long the effects of Cialis last and how to use it correctly.

What is Cialis?

Cialis is a prescription oral tablet used to treat mild to moderate erectile dysfunction (ED), benign prostatic hyperplasia (BPH), and pulmonary arterial hypertension.

Erectile dysfunction is the inability to achieve or maintain an erection.

Benign prostatic hyperplasia is an enlarged prostate and generally happens if you are an older man and can cause urinary symptoms.

Pulmonary arterial hypertension is high blood pressure in the arteries of your lungs which can cause your heart to weaken or fail because it has to work harder to provide these areas with blood.

Cialis is defined as a phosphodiesterase type-5 inhibitor or PDE5 inhibitor. In other words, it works by relaxing muscles and increasing blood flow to certain areas of your body.

Taking Cialis does not cure erectile dysfunction, benign prostatic hyperplasia, or pulmonary hypertension, but it may provide relief from the symptoms of these conditions.

It is also important to note that Cialis is a prescription drug for men only and you can not use it if you are a woman.

How does Cialis work?

The active ingredient in Cialis is tadalafil which also happens to be its name when you get it in its generic version.

As noted above, tadalafil works by inhibiting an enzyme called PDE type 5 which allows the smooth muscle cells in the walls of your blood vessels to relax, which then increases blood flow.

For erectile dysfunction, this means that more blood will flow to your penis which will make it easier for you to achieve and maintain an erection but only if you receive sexual stimulation.

If you have benign prostatic hyperplasia, this means that the enlarged prostate will not constrict the urethra as much which will make urinating easier.

Finally, for pulmonary arterial hypertension, taking Cialis means that your high blood pressure (hypertension) in your lungs will be lowered since Cialis is a vasodilator, meaning it widens blood vessels and arteries which increases your blood flow.

From this point forward we will only focus on Cialis as a treatment for erectile dysfunction.

How long do the effects of Cialis last?

Cialis can be taken as needed or as a daily medication depending on what your doctor prescribed for you.

The effects of Cialis for erectile dysfunction can last up to 36 hours after you take the medication which is why it is sometimes called “the weekend pill” due to its ability to have long-lasting effects for the majority of the weekend.

The effects of Cialis will not be immediate, it may take 30 minutes to up to 2 hours for the medication to work. Do not take more than one dose of Cialis in a 24-hour period.

What are the side effects of Cialis?

The most common side effects of Cialis are as follows:

  • Headache
  • Flushing (reddening of your skin on your face, back, or chest)
  • Indigestion
  • Muscle aches
  • Nasal congestion
  • Back pain

These side effects are usually mild and can take up to 24 hours after your dose to start but usually resolve themselves within a couple of days.

If you are prescribed to take Cialis daily, you may also experience:

  • Urinary tract infections (UTIs)
  • Sore throat
  • Diarrhea
  • Acid reflux
  • Stomach pain
  • Cough
  • Respiratory infections

On rare occasions, Cialis may also cause some severe adverse effects and these include:

  • Low blood pressure which may cause dizziness, fainting, or even a heart attack
  • A painful erection lasting longer than 4 hours which is also called priapism
  • Abnormal vision or hearing that can include loss of vision, tinnitus (ringing in your ears), dizziness, or loss of hearing

If you suffer any of these severe side effects, please call 911 or seek immediate medical attention.

What is the best way to use Cialis?

Cialis is a prescription medication and you need to always follow your doctor’s instructions when taking it.

The usual recommended starting dose for Cialis is either a single tablet as needed or a tablet that is taken daily, preferably at the same time every day.

For most men, the recommended dosage is 10mg but depending on how well it works for you and how often you plan on having sex, your doctor may start you off with a lower dose or increase your dosage.

It is important that you do not take more than one tablet of Cialis in a 24-hour period regardless of the dosage prescribed to you.

You can take Cialis with or without food but if you take it with a high-fat meal, it may take longer for the medication to start working.

Does Cialis interact with other medications?

Cialis does not interact with many medications or supplements but there are some that can cause problems when used together. These include:

  • Nitrate medications which are often used to treat chest pain also called angina, and as a high blood pressure medication and include nitroglycerin and alpha-blockers
  • Rifampin is an antibiotic used to treat tuberculosis
  • Certain other antibiotics
  • Antiseizure medications that are usually used to treat epilepsy
  • HIV medications
  • Oral antifungal medications
  • St. John's wort

If you are on any of these medications, your doctor will likely not prescribe Cialis to you or they may start you on a lower dosage.

Taking Cialis with other drugs that lower your blood pressure may cause a sudden decrease in blood pressure to an unsafe level.

You need to also avoid grapefruit juice as it can lead to an increase in side effects and also only consume alcohol in moderation.

Avoid taking Cialis with a meal that is high in fat as it may make it take longer to work for you.

Before starting any new medication or health supplement always discuss with your doctor your medical history and what medications you are currently taking.

Who else needs to avoid taking Cialis?

Cialis is not right for everyone and there if you have certain medical conditions you may need to avoid taking this medication.

These include:

  • Heart problems such as heart disease that make you unsuitable for having sex
  • Retinal eye problems
  • Severe liver disease
  • Irregular heartbeats
  • Chest pains or heart pains (angina)
  • Heart failure
  • Uncontrolled blood pressure

You need to also avoid Cialis if you have had an allergic reaction to tadalafil in the past. If you are unsure if Cialis is right for you, please speak with your doctor or health care provider.

What are the differences between Cialis and Viagra?

Cialis is very similar to Viagra and Levitra, which are all PDE-inhibitors that help you achieve and maintain an erection when you are sexually aroused.

The main difference between Viagra and Cialis is that Viagra lasts only 4-6 hours while Cialis can last up to 36 hours.

Taking Cialis can allow you to be more spontaneous with your sexual activity as you do not have a small window to plan for having sex. If you take Cialis, you may also experience muscle pains in your arms and legs although this is not common.

Summary

Cialis is a popular erectile dysfunction medication that works by inhibiting the PDE5 enzyme and increasing blood flow to your penis to help get and maintain a stronger erection.

It is available as a daily pill or an as-needed pill and can last up to 36 hours.

There are some side effects associated with Cialis including headaches, flushing, and indigestion among many others but they are usually mild.

Cialis does interact with some medications and supplements and you need to talk to your doctor about any of them you may be taking before your start taking Cialis.

Viagra is a similar medication to Cialis and the main difference between the two is that Viagra lasts for a much shorter period of time. If you think Cialis may be right for you, please speak with your doctor or health care provider about getting a prescription.

References, Studies and sources:

https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/questions-and-answers-cialis-tadalafil

https://www.goodrx.com/tadalafil-cialis/how-to-take-cialis-avoid-side-effects-and-get-best-results

https://www.healthline.com/health/mens-health/cialis#other-options

https://www.drugs.com/tips/cialis-patient-tips

https://www.healthline.com/health/how-to-get-maximum-effect-from-cialis

https://www.webmd.com/drugs/2/drug-77881/cialis-oral/details

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