Viagra ( Sildenafil )

Cialis (tadalafil) vs. Viagra (sildenafil)

Cialis (tadalafil) and Viagra (sildenafil) are oral drugs that are used for treating impotence (the inability to attain or maintain a penile erection) and benign prostatic hyperplasia (BPH). They are in a class of drugs called phosphodiesterase-5 (PDE5) inhibitors that also includes vardenafil (Levitra, Staxyn ODT), and avanafil (Stendra).

Penile erection is caused by the engorgement of the penis with blood. Under normal conditions, sexual stimulation leads to the production and release of nitric oxide in the penis. Nitric oxide then activates the enzyme, guanylate cyclase, which causes the production of cyclic guanosine monophosphate (cGMP). It is the cGMP that is primarily responsible for the erection by affecting the amount of blood that the blood vessels deliver and remove from the penis. Cialis and Viagra inhibit an enzyme called phosphodiesterase-5 (PDE5) which destroys the cGMP. Thus, Cialis and Viagra prevent the destruction of cGMP and allows cGMP to accumulate and persist longer. The longer cGMP persists, the more prolonged the engorgement of the penis.

SLIDESHOW

What are the side effects of Cialis and Viagra?

Cialis

WARNING

If you are taking Cialis and you have nausea, chest pain or dizziness during sex, seek medical help immediately as you may have a life-threatening condition.

The most common side effects of tadalafil are:

  • facial flushing (reddening), ,
  • stomach upset, , symptoms, and .

Tadalafil also may cause:

    , ,
  • changes in color vision, and
  • abnormal ejaculation. , or an erection that lasts more than four hours that can damage the penis

Viagra

WARNING

If you are taking Viagra and you have nausea, chest pain or dizziness during sex, seek medical help immediately as you may have a life-threatening condition.

Approximately 15% of persons taking Viagra experience side effects. The most common side effects are:

  • facial flushing (1 in 10), (1 in 6),
  • stomach pain, ,
  • nausea, , , (UTIs) , and
  • an inability to differentiate between the colors green and blue. , or an erection that lasts more than four hours that can damage the penis

Latest Men’s Health News

Daily Health News

Trending on MedicineNet

What is the dosage of Cialis vs. Viagra?

Cialis

For most individuals, the recommended starting dose of tadalafil is 10 mg per day taken before sexual activity (tadalafil for use as needed).

Depending on the adequacy of the response or side effects, the dose may be increased to 20 mg or decreased to 5 mg a day. The effect of tadalafil may last up to 36 hours. Individuals who are taking medications that increase the blood levels of tadalafil should not exceed a total dose of 10 mg in 72 hours (See drug interactions). For once daily use without regard to sexual activity, the recommended dose is 2.5 to 5 mg daily. Tadalafil should not be taken more than once daily.

The recommended dose for BPH, or BPH and ED is 5 mg daily taken about the same time each day. Tadalafil may be taken with or without food since food does not affect its absorption from the intestine.

The dose of tadalafil may require adjustment for patients with reduced kidney or liver function.

Viagra

  • The usual recommended dose is 25 to 100 mg 1 hour before sexual activity.
  • The maximum dose is 100 mg daily.
  • The elderly (over 65 years of age) should start at 25 mg before sexual activity. is rapidly absorbed. Maximum observed plasma concentrations are reached within 30 to 120 minutes (median 60 minutes) of oral dosing in the fasted state. When sildenafil is taken with a high fat meal, the rate of absorption is reduced, with an average delay in the time to maximal concentration of 1 hour.

QUESTION

What drugs interact with Cialis and Viagra?

Cialis

The breakdown and elimination of tadalafil from the body may be decreased by erythromycin, ketoconazole (Nizoral), itraconazole (Sporanox), indinavir (Crixivan) and ritonavir (Norvir). Therefore, these drugs may increase the levels of tadalafil in the blood. If these drugs are being used at the same time as tadalafil, the dose of tadalafil should be reduced to 10 mg every 72 hours when used as needed or 2.5 mg when used daily in order to avoid side effects from high levels of tadalafil.

Rifampin, carbamazepine (Tegretol, Tegretol XR, Equerto, Carbatrol), phenytoin (Dilantin, Dilantin-125), and phenobarbital may decrease blood levels of tadalafil, possibly reducing the effect of tadalafil.

Tadalafil exaggerates the increases in heart rate and lowering of blood pressure caused by nitrates, for example, nitroglycerin, isosorbide dinitrate (Isordil), isosorbide mononitrate (Imdur, Ismo, Monoket), nitroglycerin (Nitro-Dur, Transderm-Nitro) that are used primarily for treating heart pain (angina). In patients who take nitrates for angina, tadalafil could cause heart pain or possibly even a heart attack by exaggerating the increase in heart rate and the lowering of blood pressure. Therefore, tadalafil should not be used with nitrates.

Tadalafil also exaggerates the blood pressure lowering effects of some alpha-blocking drugs for example, terazosin (Hytrin) that primarily are used for treating high blood pressure or enlargement of the prostate (BPH). Individuals who take these alpha-blockers should be on a stable dose of the alpha-blocker before tadalafil is started. In such situations, tadalafil should be started at the lowest dose. If the patient is already taking tadalafil, the alpha-blocker should be started at the lowest dose. Combining tadalafil with alpha-blockers for treatment of BPH is not recommended.

Tadalafil and alcohol both lower blood pressure. Therefore, combining tadalafil with alcohol may cause excessive drops in blood pressure and cause dizziness, headaches, and increased heart rate.

PDE5 inhibitors may affect platelet function and therefore prolong bleeding. Tadalafil should be used cautiously in patients with bleeding disorders or active ulcers. Tadalafil should not be combined with Adcirca (another form of tadalafil) or other PDE5 inhibitors, for example, vardenafil (Levitra) or sildenafil (Viagra, Revatio).

Viagra

Viagra increases the effects of the blood pressure lowering medications. It also increases the blood pressure lowering effects of nitrates, for example, isosorbide dinitrate (Isordil), isosorbide mononitrate (Imdur, Ismo, Monoket), nitroglycerin (Nitro-Dur, Transderm-Nitro) that are used primarily for treating angina. Patients taking nitrates should not receive Viagra.

Patients should not combine Viagra with other PDE5 inhibitors (for example, vardenafil [Levitra], tadalafil [Cialis]).

Cimetidine (Tagamet), erythromycin, ketoconazole (Nizoral), itraconazole (Sporanox), atazanavir (Reyataz), and mibefradil (Posicor) can cause marked increases in the amount of Viagra in the body. Patients taking these medications should be observed carefully if sildenafil is used.

It is expected that rifampin will decrease blood levels of Viagra and probably reduce its effectiveness.

Are Cialis and Viagra safe to use while pregnant and breastfeeding?

Cialis

Tadalafil is not approved for women and has not been evaluated in women who are breastfeeding.

Viagra

Although extensive testing in animals has demonstrated no negative effects on the fetus, Viagra has not been studied in pregnant women. There is no effect on sperm count or motility of sperm in men.

It is not known whether sildenafil is excreted into breast milk.

Subscribe to MedicineNet’s General Health Newsletter

By clicking Submit, I agree to the MedicineNet’s Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet’s subscriptions at any time.

Multimedia: Slideshows, Images & Quizzes

Erectile Dysfunction (ED) Causes and Treatment

Having erection problems? What is erectile dysfunction (ED)? Learn about erectile dysfunction causes and treatments such as drugs.

Enlarged Prostate (BPH) Symptoms, Diagnosis, Treatment

Benign Prostatic Hyperplasia (BPH) is a condition cause by an enlarged prostate. Get more information on how an enlarged prostate.

Healthy Aging: Better Sex After 50

It’s never too late to improve your sex life. Learn how older adults can overcome common health conditions affecting seniors over.

Sex-Drive Killers: The Causes of Low Libido

Noticing a lack of intimacy with your partner? Here we explore how stress, lack of sleep, weight gain, depression and low T can.

Sex Tips for Men: How to Have a Better Sex Life

Learn sex tips for men that lead to more sexual pleasure such as better communication, focusing on pleasurable sensations.

What Kind of Doctor Do I Need? Find a Specialist

Do I need my primary care doctor or should I see a specialist? Finding the right doctor is daunting. We make it easier.

Benign Prostatic Hyperplasia (Enlarged Prostate) Quiz

Take the Enlarge Prostate Quiz and challenge your knowledge of prostate problems. Learn causes, symptoms, treatments, and.

Erectile Dysfunction (Impotence) Quiz: Causes & Treatment

Did you know that certain medical condition may be responsible for ED? Some causes of impotence are medically treatable and.

Related Disease Conditions

Sexual Problems in Men

Male sexual dysfunction can be caused by physical or psychological problems. Common sexual problems in men include erectile dysfunction (impotence or ED), premature ejaculation, and loss of libido. Treatment for sexual dysfunction in men may involve medication, hormone therapy, psychological therapy, and the use of mechanical aids.

Erectile Dysfunction (ED, Impotence)

Erectile dysfunction (ED, impotence) is the failure to achieve or maintain an erection. There are many potential underlying causes of erectile dysfunction, including stress and emotional problems, brain dysfunction, problems with blood supply to the penis, and structural problems with the penis.

Prostatitis vs. BPH (Enlarged Prostate): What Is the Difference?

Prostatitis and BPH (benign prostatic hyperplasia, enlarged prostate gland) are both conditions of the prostate gland. There are four types of prostatitis that can be caused by infections (usually bacterial) or other health conditions or problems, acute bacterial prostatitis (type I), chronic bacterial prostatitis (type II), chronic prostatitis and chronic pelvic pain syndrome (type III), and asymptomatic inflammatory prostatitis (type IV). BPH is inflammation of the prostate gland, and most men have the condition by age 50. Doctor's don't know what causes this inflammation, but they theorize that it may be related to hormones. Both of these conditions can cause similar symptoms like low back pain, pain during urination, or difficulty or the inability to urinate. However, prostatitis has many more symptoms and signs than BPH, and they based on the type of prostatitis. Examples include low back pain and/or abdominal pain, painful urination, fever, chills, feeling tired, recurrent urinary tract infections (UTIs), painful urination intermittently, intermittent obstruction urinary tract symptoms (frequent, painful, or incomplete urination), pelvic pain and/or discomfort, pain with ejaculation, and erectile dysfunction (ED). If you think you have either of these conditions contact your doctor or other health care professional. Bacterial prostatitis can be cured with antibiotics; however, there is no cure for BPH.

Enlarged Prostate (BPH, Benign Prostatic Hyperplasia)

Benign prostatic hyperplasia (BPH or enlarged prostate) is very common in men over 50 years of age. Half of all men over the age of 50 develop symptoms of BPH, but few need medical treatment. This noncancerous enlargement of the prostate can impede urine flow, slow the flow of urine, create the urge to urinate frequently and cause other symptoms like complete blockage of urine and urinary tract infections. More serious symptoms are urinary tract infections (UTIs) and complete blockage of the urethra, which may be a medical emergency. BPH is not cancer. Not all men with the condition need treatment, and usually is closely monitored if no symptoms are present. Treatment measures usually are reserved for men with significant symptoms, and can include medications, surgery, microwave therapy, and laser procedures. Men can prevent prostate problems by having regular medical checkups that include a prostate exam.

Can You Take Viagra With Testosterone?

Sildenafil (Viagra) is a medication used to treat erectile dysfunction in men. Sildenafil increases the blood flow to the penis, causing an erection. Viagra as such doesn’t cure erectile dysfunction permanently and it doesn’t increase sexual desire/drive. The effects usually wear away in a few hours.

Sex, Urinary, and Bladder Problems of Diabetes

Having diabetes can mean early onset and increased severity of bladder symptoms (urinary incontinence and urinary tract infections) and changes in sexual function. Men may have erectile dysfunction; and women may have problems with sexual response and vaginal lubrication. Keep your diabetes under control, and you can lower your risk of sexual and urologic problems.

Sexual Health

Sexual health information including birth control, impotence, herpes, sexually transmitted diseases, staying healthy, women’s sexual health concerns, and men’s sexual health concerns. Learn about the most common sexual conditions affecting men and women.

Treatment & Diagnosis

Medications & Supplements

Prevention & Wellness

Healthy Resources
Featured Centers
Health Solutions From Our Sponsors
  • Shot-Free MS Treatment
  • Your Child and COVID-19

Health Solutions From Our Sponsors

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

©1996-2021 MedicineNet, Inc. All rights reserved. Terms of Use. MedicineNet does not provide medical advice, diagnosis or treatment. See additional information.