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Sildenafil oral tablet vs. Cialis: A detailed guide

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Sildenafil oral tablet and Cialis (tadalafil) are prescription drugs used to treat erectile dysfunction. Both medications have other uses. They both come as tablets you’ll take by mouth.
Medically reviewed by Michael Rio, PharmD
Updated on

This article explains how sildenafil oral tablet and Cialis are similar and different. You can view detailed articles about sildenafil oral tablet and Cialis if you’d like more information about these drugs.

Cost of sildenafil and Cialis

As with the cost of other medications, the cost of sildenafil oral tablet and Cialis can vary. Their price may be affected by:

  • whether they’re covered by health insurance, if you have coverage
  • the pharmacy they’re purchased from

Coupons and cost savings

To view drug prices when Optum Perks coupons are applied, see this page for sildenafil oral tablet and this one for Cialis. You can also check with your doctor, pharmacist, or insurance provider.

The options described in this article may also help you save on your prescription.

Download the free Optum Perks Discount Card to save up to 80% on some prescription medications.

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Note: Optum Perks coupons cannot be used with insurance copays or benefits.

Questions about sildenafil and Cialis

Below, you’ll find answers to some common questions about sildenafil oral tablet and Cialis.

Is it safe to take sildenafil and Cialis together?

No, it’s likely not. Doctors usually avoid prescribing these medications together.

Sildenafil and Cialis work in the same way and can cause similar side effects. These include serious side effects such as low blood pressure and priapism (erections lasting longer than 4 hours). You may have an increased risk of these side effects if you take these medications together.

If you have more questions about this, talk with your doctor or pharmacist. For more details about these drugs’ side effects, see the “Side effects of sildenafil and Cialis” section below.

How do sildenafil and Cialis compare with Levitra?

Sildenafil, Cialis (tadalafil), and Levitra (vardenafil) are all medications used to treat erectile dysfunction (ED). Sildenafil and Cialis are also prescribed for other uses. (For more details, see the “Uses of sildenafil and Cialis” section below.) These medications all belong to the same group of drugs. They have some similarities and some differences.

Note that Levitra is no longer available in the United States. But generic versions of the drug (vardenafil) are available.

To learn more about how sildenafil, Cialis, and vardenafil compare, talk with your doctor.

Between sildenafil and Cialis, is one a better treatment for ED?

Doctors may prescribe either sildenafil oral tablet or Cialis to treat ED. In studies, sildenafil oral tablet and Cialis were both effective for this purpose.

That said, these medications differ in some ways. For instance:

  • Cialis lasts longer in your body than sildenafil (up to 36 hours for Cialis compared with up to 4 hours for sildenafil).
  • Both drugs can be taken as needed for sexual activity, but Cialis can also be taken on a regular daily basis to allow for a more spontaneous sex life.

Keep in mind that your results from taking sildenafil oral tablet or Cialis may differ from those seen in studies.

Your doctor can help determine whether one option is better for your condition. They’ll recommend this based on your specific needs and health factors.

Talk with your doctor if you’d like to learn more about which drug is right for you.

Side effects of sildenafil and Cialis

Sildenafil oral tablet and Cialis may cause mild or serious side effects. Some of the more common mild side effects of each drug are listed below. Serious side effects of sildenafil oral tablet and Cialis are also listed.

Keep in mind that your side effects may differ from those listed below. They can vary based on your overall health, any other medications you take, and your age.

This article doesn’t include all possible side effects of these medications. To find more information, you can view the prescribing information for sildenafil oral tablet and Cialis. You can also check out these articles about sildenafil oral tablet side effects and Cialis side effects.

Mild side effects

Below are some of the mild side effects reported with sildenafil oral tablet and Cialis:

 sildenafil oral tabletCialis
headache
flushing (temporary warmth, redness, or deepening of skin color)✓ 
indigestion (upset stomach)
stuffy nose✓ 
mild allergic reaction*

* An allergic reaction is possible with sildenafil oral tablet and Cialis. But it’s unclear whether it occurred in studies for sildenafil oral tablet and Cialis.

Serious side effects

Below are serious side effects reported with sildenafil oral tablet and Cialis:

 sildenafil oral tabletCialis
priapism (erection lasting more than 4 hours)
low blood pressure✓ 
vision or hearing problems✓ 
serious allergic reaction*

* An allergic reaction is possible with sildenafil oral tablet and Cialis. But it’s unclear whether it occurred in studies for sildenafil oral tablet and Cialis.

With many drugs, serious side effects are possible, but they’re not common. If you have serious side effects from sildenafil oral tablet or Cialis, call your doctor right away. If your symptoms are severe or you’re having a medical emergency, call 911 or a local emergency number.

Generic versions

Below is information about whether sildenafil oral tablet or Cialis is available in a generic version.

A generic medication is an identical copy of the active ingredient in a brand-name medication. (An active ingredient is what makes a medication work.) Generics usually cost less than brand-name drugs. And they’re thought to be as safe and effective as the brand-name versions.

Sildenafil oral tablet is a generic version of the brand name drugs Viagra and Revatio. Cialis is a brand-name drug. It’s also available in a generic version called tadalafil.

If your doctor prescribed sildenafil oral tablet, but you’d like to know about taking a brand-name version, let your doctor or pharmacist know. They can help determine whether the brand-name version is right for you.

If your doctor prescribed Cialis, but you’d like to know about taking its generic version, let your doctor or pharmacist know. They can help determine whether the generic version is right for you.

Uses of sildenafil and Cialis

Here’s a summary of sildenafil oral tablet’s and Cialis’s approved uses:

 sildenafil oral tabletCialis
Approved uses(ED)*
pulmonary arterial hypertension (PAH) (high blood pressure in the artery that carries blood from your heart to lungs)
• ED
benign prostatic hyperplasia (BPH), also known as enlarged prostate gland
• ED and BPH together
Prescribed toadultsadults

* With ED, you have trouble getting or keeping an erection.

Doctors may not prescribe Cialis in certain situations, such as 26 weeks after taking Cialis with finasteride (Proscar). This combination may be used to start BPH treatment, but your doctor may recommend that you do not take the combination for more than 26 weeks.

If you’d like to know more about taking either medication for your condition, ask your doctor. They can recommend whether sildenafil oral tablet or Cialis is an option to consider.

Dosage of sildenafil and Cialis

Below is dosage information for the condition that both sildenafil oral tablet and Cialis are prescribed to treat. To find detailed dosage information for all conditions that sildenafil oral tablet and Cialis treat, see these articles for sildenafil oral tablet dosage and Cialis dosage.

The following dosages are provided by the makers of sildenafil oral tablet and Cialis. If your doctor prescribes either medication, you should follow the dosage they prescribe. They’ll advise the dosage that’s best for your condition. Do not adjust your dosage without first talking with your doctor.

Sildenafil’s dosage

Below is a summary of sildenafil oral tablet’s recommended dosage in adults. Strength is measured in milligrams (mg).

Condition How it’s takenRecommended doseFrequency
(ED) in adults oral tablet50 mgtaken about 1 hour before sexual activity (no more than once per day)
PAH in adults oral tablet20 mgtaken three times per day

Cialis’s dosage

Below is a summary of Cialis’s recommended dosages in adults. Strength is measured in mg.

ConditionHow it’s takenRecommended doseFrequency
ED in adults (as needed use) oral tablet10 mgtaken at least 30 minutes before sexual activity (no more than once per day)
ED in adults (daily use) oral tablet2.5 mgtaken once per day, at the same time each day
benign prostatic hyperplasia in adultsoral tablet5 mgtaken once per day, at the same time each day

Warnings for sildenafil and Cialis

Some medications may not be recommended for you if you have certain factors affecting your health. These are referred to as a drug’s warnings.

Some people should not take sildenafil oral tablet or Cialis, and others should take either medication with caution.

Warnings for sildenafil oral tablet and Cialis are summarized below. Before taking either medication, talk with your doctor about your health conditions, past surgeries, and any medications you take. Your doctor can recommend whether either drug is safe for you.

Warnings for sildenafil oral tablet and Cialis are summarized in the table below:

 sildenafil oral tabletCialis
taking nitrate drugs or riociguat (Adempas)
taking certain other drugs✓ 
high or low blood pressure
heart conditions
past stroke
liver or kidney conditions
blood cell conditions
penis shape conditions, such as Peyronie’s disease
certain vision conditions
stomach ulcers
allergic reaction to either drug or any of their ingredients✓ ✓ 
currently pregnant or planning to become pregnant
currently breastfeeding or planning to breastfeed

You can view more detailed articles about sildenafil oral tablet and Cialis if you’d like to know more about warnings for these drugs. You can also view the prescribing information for sildenafil oral tablet and Cialis.

What to ask a doctor

If you’re trying to decide whether sildenafil oral tablet or Cialis is better for you, talk with your doctor. They can recommend the best option.

Here’s a list of questions you may want to ask your doctor:

  • Are sildenafil oral tablet and Cialis affected by food or drink?
  • Do either of these drugs have any long-term side effects?
  • Do these drugs have similar interactions with other medications?

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

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