Viagra and Cialis are the most commonly prescribed erectile dysfunction medications. Healthcare providers order these prescription drugs to help patients achieve and maintain an erection firm enough for sex.

But which drug, Viagra or Cialis, is the best choice for you? This article examines the similarities and differences between these two brand-name drugs. We’ll also cover some precautions and side effects you should know about before taking either one.

What are Viagra and Cialis used to treat?

Healthcare professionals prescribe both Viagra and Cialis to treat erectile dysfunction (ED).

Erectile dysfunction affects over 18 million men in the United States. It's a common sexual dysfunction. It occurs when a man can't achieve or maintain an erection for sex.

Most men will have trouble getting an erection during sex at some point. Continued trouble is considered erectile dysfunction. Many providers will start treating erectile dysfunction with lifestyle changes. These may include a healthy diet and regular exercise. They may also offer mental health care. This can treat possible psychological causes of sexual dysfunction.

When these therapies fail, providers turn to ED medication for a more targeted approach.

Viagra is only indicated as a treatment option for erectile dysfunction. Cialis is approved to treat ED. It is also indicated as a treatment option for benign prostatic hyperplasia (BPH) or an enlarged prostate.

Viagra and Cialis are brand-name erectile dysfunction drugs. They are available in their brand name form. Generic versions are also available. Generic Viagra is called sildenafil, which is the active ingredient in Viagra. Generic Cialis is called tadalafil, the active ingredient in Cialis.

How do these drugs work?

Cialis and Viagra are both phosphodiesterase 5 (PDE5) inhibitors. When sexually stimulated, nerve signals release chemicals. These chemicals cause the production of nitric oxide. This leads to relaxation and widening of blood vessels in the penis, increasing blood flow and causing an erection.

PDE5 inhibitors like Viagra and Cialis block an enzyme called phosphodiesterase type 5 (PDE-5) in the smooth muscle cells of blood vessels. This enzyme usually breaks down a molecule called cGMP, crucial for maintaining blood vessel relaxation. By inhibiting PDE-5, these drugs prevent cGMP from being broken down. This accumulates cGMP in the blood vessel walls, leading to further relaxation of blood vessels. This leads to increased blood flow, which is crucial for achieving and maintaining a longer-lasting erection.

What’s the difference between Cialis and Viagra?

Cialis and Viagra work in a very similar way. They are also both FDA-approved to treat erectile dysfunction in men. When comparing these two drugs, there are a few differences to keep in mind:

How fast they work: Viagra starts to work within 30 minutes of taking the drug. It may take 45-60 minutes before you fully feel its effects.

Cialis starts to work within 30 minutes of taking the drug. It may take up to 2 hours before you fully feel its effects.

How long they work: The effects of Viagra last up to 8 hours. The effects of Cialis last up to 36 hours (about a day and a half).

How to take them: Viagra should be taken on an empty stomach an hour before sexual stimulation. Wait for at least an hour or two after a meal before taking Viagra. Note that high-fat meals and alcohol can slow the onset of this drug’s effects. Therefore, it’s best to stick to a light, low-fat meal with no alcohol before taking Viagra.

Cialis can be taken on an empty or full stomach. Food does not affect the onset of Cialis’ effects.

Typical dosage: You should take Viagra on an "on-demand" basis. This means that it is not taken every day. Instead, it is taken just before sexual activity. The initial dose is usually 50 mg, to be taken an hour before sexual activity. If side effects occur, the dosage may be lowered to 25 mg. If 50 mg is ineffective, a higher dose (up to 100 mg) may be prescribed.

Cialis can be taken every day or occasionally before sexual activity. The starting dose of Cialis is usually 2.5 mg. The daily dose may be increased or decreased depending on the patient’s needs. It may also change based on whether the medication causes any side effects.

What are the common side effects of Cialis and Viagra?

Cialis and Viagra cause similar side effects.

Common side effects of Cialis and Viagra include:

• Headache
  
• Heartburn
  
• Indigestion
  
• Nasal congestion
  
• Nausea
  
  

More severe common side effects include:

• Painful erections that last for more than 4 hours (priapism)
  
• Ringing in the ears
  
• Sudden loss of vision
  
• Sudden loss of hearing
  
• Chest pain
  
• Shortness of breath
  
• Pain during urination
  
• Dizziness
  
• Skin rash/ Hives
  
• Swelling
  
  

If you begin to notice any side effects while taking Cialis or Viagra, inform your healthcare provider right away. If they do not go away within a few days or become severe, seek medical attention immediately.

What are the unique side effects of Cialis?

Cialis and Viagra cause many similar side effects. In addition, each medication causes unique adverse effects.

Unique side effects of Cialis:

• Back pain
  
• Muscle pain
  
• Limb pain
  
• Low blood pressure
  
  

Tell your doctor as soon as you notice any side effects. They may order a lower dose of Cialis or may provide medical advice to help avoid these reactions. If the side effects do not go away or become severe, seek medical attention immediately.

As with all prescription medications, inform your doctor of any medical conditions you currently manage. Tell them about all medications, over-the-counter or prescription drugs, and supplements you are taking before starting treatment with Cialis.

Drug interactions may occur if you are taking other medications along with Cialis. Drug interactions are reactions between two or more drugs. These reactions often result in unexpected and harmful side effects. Informing your provider about the drugs you are taking will help you avoid potentially dangerous side effects.

You should mention if you are taking medications such as:

• Nitrates (like nitroglycerin)
  
• Alpha-blockers
  
• Anti-fungal medication
  
• HIV protease inhibitors
  
• St. John’s Wort
  
  

You should specifically mention health conditions like:

• High blood pressure (hypertension)
  
• Low blood pressure (hypotension)
  
• Heart disease
  
• Heart attack
  
• Angina (chronic chest pain)
  
• Stroke
  
• High cholesterol
  
• Diabetes
  
• Stomach ulcers
  
• Bleeding disorders
  
• Blood cell problems
  
• Kidney or liver disease
  
  

What are the unique side effects of Viagra?

Side effects unique to Viagra include:

• Vision changes
  
• Changes in color vision (seeing a blue tint or having a hard time distinguishing between blue and green)
  
• Sensitivity to light
  
  

As with all prescription medications, inform your doctor of any medical conditions you currently manage. Tell them about all medications, over-the-counter or prescription drugs, and supplements you are taking before starting treatment with Viagra.

You should mention if you are taking medications such as:

• Nitrates
  
• Cimetidine (Tagemet HB)
  
• St. John’s Wort
  
  

You should specifically mention health conditions like:

• Tobacco use
  
• Dehydration
  
• Heart disease
  
• Kidney disease
  
• Liver disease
  
• Irregular heartbeat
  
• Angina
  
• Stroke
  
• High or low blood pressure
  
• High cholesterol
  
• Bleeding problems
  
• Blood cell problems
  
• Conditions affecting the penis
  
• Diabetes
  
• Medical conditions affecting eyesight
  
  

Should I take Cialis or Viagra?

Talk to your healthcare provider about Cialis and Viagra. These medications are very similar, with a few key differences between them. The decision to prescribe one over the other will depend on your needs and health history.

Cialis can be taken every day. It lasts longer than Viagra and can be taken with or without food. However, Cialis takes longer before its full effects can be felt. Because it lasts longer, it also may cause longer-lasting side effects. These include limb pain, nausea, diarrhea, and low blood pressure.

Viagra is taken as needed. It should not be taken every day. The effects of Viagra come on quicker than Cialis, but Viagra does not last as long as Cialis. While this means that the effects of Viagra are shorter-lived, it also means that side effects may not last as long.

Discuss these options with your healthcare provider. Note that all prescriptions are at the discretion of your provider. Do not adjust or alter your dosage or try any new medications without consulting them first.

Are there alternatives to Cialis and Viagra?

Yes.

Alternative PDE5 inhibitors include:

• Levitra (vardenafil)
  
• Stendra (avanafil)
  
  

These drugs work similarly to Cialis and Viagra. Talk to your provider about all these treatment options to get the best prescription for you and your sex life.

Can I get ED treatment on Sesame?

Yep! Sesame offers convenient and discreet online ED treatment. These quick video appointments allow you to discuss your symptoms and potential treatment options with a licensed healthcare provider.

If appropriate, providers on Sesame can prescribe ED meds and other forms of therapy to help you get your sex life back on track.

Note that an online ED treatment appointment does not guarantee a prescription.

Sources:

• (2017). Symptoms & Causes of Erectile Dysfunction. NIDDKD.
  
• Coward, R. M., & Carson, C. C. (2008). Tadalafil in the treatment of erectile dysfunction. NIH.
  
• Hatzimouratidis K. (2006). Sildenafil in the treatment of erectile dysfunction: an overview of the clinical evidence. NIH.
  
• Lowy, M., & Ramanathan, V. (2022). Erectile dysfunction: causes, assessment and management options. NIH.