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Drug vs. Drug

Cialis vs. Viagra: Differences, similarities, and which is better for you

Gerardo Sison medical writer headshot By | December 18, 2019

Drug overview & main differences | Conditions treated | Efficacy | Insurance coverage and cost comparison | Side effects | Drug interactions | Warnings | FAQ

If you are experiencing erectile dysfunction (ED), there are many options available to help you. Treatment options for ED include psychological, lifestyle, and medication therapies. Two of the most commonly prescribed medications include Cialis (tadalafil) and Viagra (sildenafil).

Cialis and Viagra are two brand name prescription drugs that can treat ED. They are grouped into a class of medications called phosphodiesterase-5 (PDE5) inhibitors and work by increasing blood flow to the penis. These drugs help a man get and maintain an erection. Other similar drugs include Levitra (vardenafil) and Stendra (avanafil).

What are the main differences between Cialis and Viagra?

Cialis is the brand-name drug for tadalafil. It was FDA-approved in 2003 and is used to treat erectile dysfunction and benign prostatic hyperplasia (BPH). Cialis can be taken as needed before sexual activity or once daily with effects lasting up to 36 hours. Cialis reaches maximum levels in the body between 30 minutes and 6 hours after taking it. It can be taken with food or on an empty stomach.

Viagra, also known by its generic name sildenafil, was approved by the FDA in 1998 and is a popular drug made by Pfizer to treat ED. Brand name Viagra is only indicated for erectile dysfunction. It is taken as needed before sexual activity with maximum levels of the drug reached within 30 minutes to 2 hours after taking it. Eating a high-fat meal with Viagra may reduce the absorption of the drug.

Main differences between Cialis and Viagra
Cialis Viagra
Drug class Phosphodiesterase type 5 (PDE5) inhibitor Phosphodiesterase type 5 (PDE5) inhibitor
Brand/generic status Generic version available Generic version available
What is the generic name?
What is the brand name?
Tadalafil
Cialis
Sildenafil
Viagra
What form(s) does the drug come in? Oral tablet Oral tablet
What is the standard dosage? Erectile dysfunction: 10 mg oral tablet before sexual activity
Once-daily use for ED: 2.5 mg oral tablet by mouth daily
BPH or BPH with ED: 5 mg oral tablet daily at the same time every day
Erectile dysfunction: 50 mg oral tablet before sexual activity
How long is the typical treatment? As needed As needed
Who typically uses the medication? Adult men aged 18 years and older Adult men aged 18 years and older

Conditions treated by Cialis vs. Viagra

Cialis is primarily used to treat ED. However, it is also approved to treat signs and symptoms from an enlarged prostate also called benign prostatic hyperplasia (BPH). Tadalafil, the active ingredient in Cialis, is available as Adcirca, which is used to treat pulmonary arterial hypertension (PAH), or high blood pressure in the lungs. Cialis can also be used off-label for Raynaud’s phenomenon, a rare blood vessel disorder.

Viagra is only FDA-approved to treat ED. Sildenafil citrate, the active ingredient in Viagra, is also manufactured as Revatio to treat pulmonary arterial hypertension (PAH). Viagra is sometimes used off-label to treat Raynaud’s phenomenon and female sexual arousal disorder.

Both Cialis and Viagra have also been prescribed to treat the different problems surrounding ED. For instance, Viagra may also help men who experience early ejaculation so they can have better control. Cialis has been shown to help men experiencing other sexual dysfunctions involving ejaculatory and orgasmic functions.

Condition Cialis Viagra
Erectile dysfunction (ED) Yes Yes
Benign prostatic hyperplasia (BPH) Yes No
Raynaud’s phenomenon Off-label Off-label
Female sexual arousal disorder No Off-label

Is Cialis or Viagra more effective?

Compared to placebo or using no medication, both Cialis and Viagra are effective at treating erectile dysfunction. Most of the differences between the two drugs have to do with how long the drug lasts, how it is taken, and the medical history of the person taking it.

Although they are both effective, Cialis may be preferred for its once-daily dosing and it’s used for treating BPH. Viagra may be preferred for its shorter half-life for those who only use it sparingly as needed.

In a meta-analysis pooling 16 different trials and analyzing over 5000 patients, Cialis and Viagra showed similar effectiveness and safety. These results were based on the International Index of Erectile Function (IIEF)-EF scale which is widely used to assess erectile function. Both drugs had similar incidences of side effects. However, those taking Cialis experienced improved sexual confidence and preferred it over Viagra due to feeling less pressure about planning with its longer-acting effects.

Another trial showed that the active ingredients in Cialis and Viagra were comparable in effectiveness. There were no significant differences between the two drugs. Cialis, however,  was suggested to offer more flexibility with its longer half-life.

If you have ED, it’s important to consult a doctor to determine which treatment option may be best for you. One medication may be more effective or preferred over the other depending on your situation.

Coverage and cost comparison of Cialis vs. Viagra

Brand name Cialis is not typically covered by Medicare and most insurance plans. Some plans may cover generic tadalafil. The average retail cost of generic tadalafil is $275 for thirty 2.5 mg tablets. With a SingleCare coupon, you can receive a discount and pay around $90-180 depending on the pharmacy.

Brand name Viagra is not usually covered by Medicare and most insurance plans. Check your insurance plan as some plans may cover generic sildenafil. The average retail cost of generic sildenafil range from $140 or nearly $400. SingleCare can help you lower this cost to about $75-140 for generic sildenafil.

  Cialis Viagra
Typically covered by insurance? No No
Typically covered by Medicare? No No
Standard dosage 2.5 mg tablets (supply of 30) 25 mg tablets (supply of 30)
Typical Medicare copay $275 $140-400
SingleCare cost $90-180 $75-140

Common side effects of Cialis and Viagra

Cialis and Viagra share several common side effects such as headache, indigestion, muscle pain, back pain, and nasal congestion. Both ED medications can also cause some degree of flushing, which is a warm feeling with a blushed skin tone, especially on the face. These side effects are due to the vasodilator effects of these drugs which relax smooth muscles in the blood vessels to increase blood flow.

In addition to these side effects, Cialis may also cause some pain in the limbs. Other side effects of Viagra include abnormal changes in vision, nausea, dizziness, and rash. Serious side effects of Cialis and Viagra can include cardiovascular, or heart, complications such as heart attack, stroke, cerebrovascular hemorrhage, palpitations, and arrhythmias especially if taken with certain other drugs (see Drug Interactions).

  Cialis
*10 mg tablet
Viagra
*50 mg tablet
Side Effect Applicable? Frequency Applicable? Frequency
Headache Yes 11% Yes 21%
Indigestion Yes 8% Yes 9%
Muscle pain Yes 4% Yes 2%
Back pain Yes 5% Yes 4%
Nasal congestion Yes 3% Yes 4%
Flushing Yes 3% Yes 19%
Pain in the arms or legs Yes 3% No
Abnormal vision Yes <0.1% Yes 2%
Nausea Yes <1% Yes 3%
Dizziness Yes <2% Yes 4%
Rash Yes <2% Yes 2%

*Consult a doctor or pharmacist for all possible side effects.

Source: DailyMed (Cialis), DailyMed (Viagra)

Drug interactions of Cialis vs. Viagra

PDE5 inhibitors like Cialis and Viagra have similar drug interactions. Cialis and Viagra should not be used with any medication that can decrease blood pressure. These medications include nitrates, alpha blockers, antihypertensives (blood pressure lowering drugs), and riociguat. Taking these medications together can cause dangerously low blood pressure.

Cialis and Viagra are both processed in the liver. Therefore, they should not be used with medications that alter the function of certain enzymes. CYP3A4 inhibitors, such as certain antibiotics, antifungals, and HIV protease inhibitor drugs, can increase the level of Cialis and Viagra in the body. CYP3A4 inducers, such as certain anticonvulsants like phenytoin or carbamazepine as well as an antibiotic called rifampin can decrease the effectiveness of Cialis and Viagra.

Cialis and Viagra should also be avoided with alcohol and grapefruit juice. Consuming alcohol or grapefruit juice may increase the side effects of ED medications.

Drug Drug Class Cialis Viagra
Nitroglycerin
Isosorbide dinitrate
Isosorbide mononitrate
Amyl nitrate
Amyl nitrite
Butyl nitrate
Nitrate Yes Yes
Riociguat Guanylate cyclase stimulator Yes Yes
Doxazosin
Tamsulosin
Terazosin
Prazosin
Alfuzosin
Alpha blocker Yes Yes
Amlodipine
Enalapril
Lisinopril
Metoprolol
Losartan
Valsartan
Antihypertensive Yes Yes
Erythromycin
Clarithromycin
Telithromycin
Rifampin
Antibiotic Yes Yes
Ketoconazole
Itraconazole
Antifungal agent Yes Yes
Ritonavir
Atazanavir
Darunavir
Indinavir
Lopinavir
Saquinavir
Protease inhibitor Yes Yes
Phenytoin
Carbamazepine
Anticonvulsant Yes Yes

*This may not be a complete list of all possible drug interactions. Consult a doctor with all medications you may be taking.

Warnings of Cialis and Viagra

ED drugs like Cialis and Viagra may cause heart complications such as heart attack, stroke, and arrhythmias, especially in those with heart health conditions. Cialis and Viagra can also cause changes in blood pressure when used with other blood pressure medications.

Prolonged erections lasting longer than 4 hours are possible with ED medications. Erections that are painful and last longer than 6 hours indicate a condition called priapism. If you experience these adverse effects, seek medical attention immediately.

Although rare, Cialis and Viagra can cause abnormal changes in vision or hearing. In more serious cases, these drugs can cause sudden hearing or vision loss.

Cialis and Viagra are not FDA approved for women or children younger than 18 years old.

Cialis and Viagra do not protect against sexually transmitted diseases (STDs). Consider other protective measures to prevent STDs.

Serious adverse effects may be more common in counterfeit ED drugs. Counterfeit Viagra may contain other ingredients or incorrect amounts of the active ingredient. Counterfeit drugs are not approved by the FDA. Make sure you are getting safe and effective drugs from a reliable source.

Frequently asked questions about Cialis vs. Viagra

What is Cialis?

Cialis, also known by its generic name tadalafil, is a prescription drug used for erectile dysfunction (ED). It can also treat men with an enlarged prostate, or benign prostatic hyperplasia (BPH). Cialis can be taken as needed or once daily with effects lasting up to 36 hours.

What is Viagra?

Viagra is also known by its generic name sildenafil. It is prescribed for erectile dysfunction (ED). Viagra is usually taken as a 50 mg tablet 30 minutes to 4 hours before sexual activity. It should be avoided with a high-fat meal which can reduce its absorption.

Are Cialis and Viagra the same?

Cialis and Viagra are in the same class of drugs called phosphodiesterase 5 (PDE5) inhibitors. However, they are not the same. Cialis contains tadalafil and Viagra contains sildenafil. They also have some different side effects and uses.

Is Cialis or Viagra better?

Cialis and Viagra are both effective for ED. Cialis may be preferred for its once-daily dosing and longer-lasting effects. If you experience erectile dysfunction and are looking for treatment, there are many doctors and specialists who can assess your ED and help you find the best option for your sex life.

Can I use Cialis or Viagra while pregnant?

No. Cialis and Viagra are not indicated for pregnant women. While some off-label uses have been reported for female sexual arousal disorder, women who are pregnant should not be taking ED medications.

Can I use Cialis or Viagra with alcohol?

It is not recommended to use Cialis or Viagra with alcohol. Alcohol can increase side effects such as dizziness and headache. Drinking alcohol with these drugs may result in low blood pressure.

How long does it take for Cialis to peak?

According to the FDA label, maximum levels of Cialis in the body are reached within 30 minutes and 6 hours after taking a single dose. Taking Cialis with or without food does not affect its absorption.

Does Cialis make you last longer?

Cialis does not affect your ability to last longer. It is used to help get and maintain an erection for sexual activity. Sexual stimulation or arousal is required for an erection with Cialis.

Can Viagra and Cialis be taken together?

Viagra and Cialis should not be taken together. Because they act in similar ways, taking them together can increase the risk of adverse side effects.