Are you curious how Cialis® works as an erectile dysfunction (ED) treatment? Maybe your doctor mentioned it as a treatment for your ED symptoms but you’re still unsure about taking it. It’s normal to want to understand what exactly it is you’re putting in your body. Knowing how a medication works helps set our expectations for what will happen when we take it.

Cialis has been used to treat ED since 2003. Millions of people have benefited from its effectiveness. It’s a safe medication when used correctly at recommended doses.

This article reviews what needs to happen in the body in order to get and maintain an erection. You’ll learn what Cialis does and does not do to help this process, as well as some tips to get the most from your treatment.

Cialis as ED treatment

To understand Cialis as an erectile dysfunction treatment, we must understand what ED is and what causes it.

What is erectile dysfunction (ED)?

Erectile dysfunction is a condition that causes consistent difficulty in getting or maintaining an erection suitable for sex. 

Many people think that ED means you can never get an erection. This is incorrect. Sometimes, you may have trouble getting an erection. Other times, you may get an erection but find staying hard to be, well, hard. Symptoms also need to happen more than once or twice. It’s not unusual to have an “off night”, so to speak. But if your symptoms are consistent, it’s time to talk with your healthcare provider.

It’s difficult to nail down one definitive “cause” for ED. Why? There are multiple factors, both physical and psychological, that contribute to getting and maintaining an erection. 

• Physically, your blood vessels must be healthy enough to relax and allow blood flow into the penis.
• Your nerves must also be in good working order - nerve signals help regulate blood flow into and out of the penis.
• Psychological and mental health factors can hinder your ability to get and maintain an erection. Depression and performance anxiety are examples that can cause ED.

It’s important to know that Cialis and other PDE5 inhibitors do not enhance libido (sex drive) or desire. So Cialis won’t work without arousal and sexual stimulation.

Over 150 million people worldwide are estimated to have ED of some severity. ED is a legitimate, rather common medical condition that can be treated. But you have to open up to your healthcare provider and be honest about your symptoms.

Risk factors for ED

Certain medical conditions and other factors raise the risk for ED. These include:

• Age: We’re more likely to develop ED as we age. There’s nothing we can do to prevent this, considering the alternative to aging is…not aging.
• Smoking: Smoking is known to increase the risk for ED, as tobacco smoke damages your blood vessels.
• Diabetes: ED is one of the most common complications of diabetes. Diabetes can damage your blood vessels, including those supplying blood to the penis.
• High blood pressure: High blood pressure squeezes and damages your blood vessels, which can make it difficult for your body to get enough blood to the penis.
• High cholesterol: High cholesterol means there’s a high level of fats in your blood, which can stick to your blood vessels and block blood flow.
• Cardiovascular (heart and blood vessel) disease: The link between ED and cardiovascular disease (CVD) is so strong, ED is considered a predictive marker for CVD, especially in younger men.
• Depression: Symptoms of depression, including feelings of worthlessness and inadequacy, can negatively impact arousal and desire, leading to ED even if there’s no issue with blood flow to the penis.

If Cialis doesn’t work for you or isn’t working anymore, it may be due to risk factors such as those above. Working with your doctor to manage other health conditions and engaging in healthy lifestyle choices can help make Cialis work more effectively.

What is Cialis?

Cialis (tadalafil) is a phosphodiesterase type 5 inhibitor (PDE-5 inhibitor). PDE5 inhibitors like Cialis are considered a first-choice treatment option for ED.

In addition to ED, Cialis is also FDA-approved to treat symptoms of benign prostatic hyperplasia (BPH), also called enlarged prostate. For BPH, Cialis is prescribed for daily use. Cialis can be taken daily to treat both ED and BPH.

How Cialis works for ED

To understand how Cialis works for ED, we’ll first dive into the physiology behind an erection.

The most important step in an erection is relaxation of smooth muscle in the penis, which allows for blood to enter. Arousal and sexual stimulation causes nerves in the penis to release nitric oxide. Nitric oxide works to relax smooth muscle in the penis, allowing blood to flow in. This blood flow creates an erection, and also maintains it. 

An erection is ended by an enzyme called phosphodiesterase (PDE). When PDE in the penis breaks down cGMP, penile smooth muscle contracts, which results in blood leaving the penis.

How does Cialis work?

Cialis works by blocking the actions of the enzyme phosphodiesterase-5 (PDE-5). PDE-5 is found in smooth muscle cells in blood vessels. PDE-5 causes smooth muscle in the penis to tighten, pushing blood out. Blocking the PDE5 enzyme keeps blood vessels open and smooth muscle relaxed.

How long does Cialis take to work?

Cialis begins working shortly after you take a dose. Some people can have sex about 30 minutes after a dose, but it may take a bit longer in others. It takes 30 minutes to 6 hours for tadalafil to reach its peak, with an average of about 2 hours to peak in the typical adult. The effects of Cialis last for up to 36 hours after a dose, when used as-needed.

Taking Cialis once daily means you’re always ready for sex and don’t need to time your dose around sex. There are different dosages for as-needed versus once-daily Cialis use, so you shouldn’t switch how or when you take Cialis without talking to your healthcare provider first.

Cialis effectiveness for ED

Cialis effectiveness for ED was determined in over 22 clinical trials involving over 4,000 participants. These studies lasted from 12 to 24 weeks. In one study, 64% of people treated with Cialis reported achieving and maintaining an erection for suitable sex, compared to only 23% of people who took placebo (pill with no active drug). Across studies, Cialis worked for the majority of people who used it, and the effect of Cialis did not go away over time.

These studies found several different Cialis dosages effective for erectile dysfunction. Getting the maximum effect from Cialis may require trying more than one dose to see what works for you. Your healthcare provider may also suggest using Cialis once-daily instead of as-needed.

Guidelines from the American Urological Association (AUA) recommend tadalafil and other PDE5 inhibitors as first-choice treatments for ED. These guidelines are made using clinical trials, real-world evidence, and expert opinion of healthcare providers specializing in urology and men’s sexual health.

Cialis safety

If you’re prescribed Cialis, it’s important to understand how to take it safely. This includes knowing about its side effects and knowing what to avoid after taking Cialis.

Common side effects of tadalafil

The most common side effects reported in clinical trials of tadalafil include:

• Headache
• Indigestion
• Back pain
• Muscle pain
• Nasal congestion
• Flushing
• Pain in your arms or legs

In most cases, these side effects go away within a few hours or days. If you’re taking tadalafil daily, mild side effects may go away as your body adjusts to the medication. Let your healthcare provider know if you have lingering side effects or if side effects interrupt your daily activities.

Less common but serious side effects

In addition to common side effects of tadalafil discussed above, there are less common but serious side effects to be aware of. These include:

• Priapism (a painful, prolonged erection requiring immediate medical treatment)
• Sudden vision loss or decrease in vision in one or both eyes
• Sudden decrease or loss in hearing
• High or low blood pressure
• Allergic reaction

Serious heart-related side effects, including heart attack and stroke, have also rarely occurred - mostly in people with pre-existing heart problems. If you have chest pain after taking Cialis, immediately call 911 or seek emergency medication care.

Things to avoid after taking Cialis

This is not an all-inclusive list of everything you should not do after taking Cialis. Your healthcare provider can give more instructions based on your health. These are just a few of the most important tips.

Avoid nitrates, including “poppers”. You should not use a nitrate such as nitroglycerin (NTG) or isosorbide mononitrate after taking Cialis. And never take recreational “poppers” such as butyl nitrite or amyl nitrite after taking Cialis. Combining Cialis and nitrates can cause a dangerous, sudden drop in blood pressure. 

Do not take another dose of Cialis or another PDE5 inhibitor. Do not take more than one dose of Cialis per day. You also shouldn’t mix Cialis with another PDE5 inhibitor such as Viagra® (sildenafil). Doing so can cause a sudden, dangerous drop in blood pressure.

Avoid consuming alcohol in excess (binge drinking). Alcohol, like Cialis, is a vasodilator. Combining the two can cause an unsafe drop in blood pressure. The manufacturer of Cialis warns that consuming more than 5 units of alcohol after taking the medication can produce low blood pressure.

What to do if Cialis isn’t working anymore

For some people, Cialis continues working for a long time. You may be able to take it to treat ED for years without issue. But what should you do if Cialis isn’t working anymore?

Incorrect use

Studies in those who reported no response to a PDE5 inhibitor like Cialis found that incorrect use accounted for up to 81% of treatment failures. 

• “Incorrect use” frequently included a lack of sexual stimulation, making this a good place to reemphasize that 1) Cialis does not increase libido or sexual desire, and 2) Cialis requires sexual stimulation to work. It will not “force” an erection. 
• Speaking of incorrect use, make sure you’re taking Cialis as directed by your healthcare provider
• Ask your healthcare provider if drug interactions between Cialis and other medications you take could affect how well it works

Adjusting Cialis dosage

Let’s assume you’re using Cialis correctly and it still isn’t working. What next? Your healthcare provider may decide to increase your Cialis dose. But you should never change your Cialis dose on your own. Always take it exactly as prescribed by your healthcare provider. Your healthcare provider may also suggest switching from as-needed to once-daily use to see if this helps Cialis work better for you.

Switching to another PDE5 inhibitor

If increasing your dose doesn’t work, your doctor may try having you switch from Cialis to another PDE5 inhibitor, such as Viagra (sildenafil), Levitra (vardenafil), or Stendra (avanafil).

Talk with a mental health expert

If Cialis and other PDE5 inhibitors aren’t working, your ED may be psychological in origin. In this case, you may benefit from working with a mental health expert. Anxiety, depression, stress, and even conflict within a relationship are all possible causes of ED that Cialis can’t treat.