The Difference of Sildenafil Citrate (Viagra) and Tadalafil (Cialis)

Cialis and Viagra are both PDE5 inhibitors used for the treatment of erectile dysfunction (ED).

Cialis is the brand name for tadalafil and Viagra is the brand name for sildenafil.

Both only work when a man is sexually aroused. Cialis lasts for around 36 hours compared with only 4 to 5 hours for Viagra. Food does not affect the activity of Cialis, whereas food may decrease the effectiveness of Viagra. Cialis can be used once daily, at a smaller dosage, and is also effective at treating benign prostatic hyperplasia (BPH). Dosage of Cialis may need to be reduced in men with liver or kidney problems and the risk of interactions may be higher than with Viagra.

1 The difference in Work Time

Cialis generally works within 16 to 45 minutes, and its activity is not affected by food. Viagra generally works within 30 minutes, and its effect may be diminished if taken soon after a high-fat meal. For this reason, Viagra is best taken on an empty stomach.

Effectiveness of all PDE5 inhibitors is similar; although reported effectiveness of Viagra, at 84% is slightly higher than that of Cialis at 81%. However, more men prefer Cialis because of their longer duration of effect.

2 The difference in usual Dosage

Cialis can be taken on an as-needed basis, or daily. Generally, daily dosages are smaller than as needed doses. Typically, Cialis is taken as a 10mg starting dose, prior to sexual activity. The effects of Cialis will last around 36 hours. The dosage may be increased to 20mg if 10mg is ineffective or reduced to 5mg if side effects are intolerable.

When Cialis is taken for daily use, the recommended initial dosage is 2.5mg once daily, or 5mg for people who also have BPH. Timing of the daily dosage does not matter in people using it solely for ED; however, those with BPH are advised to take it at the same time each day. Do not take more than one dose a day but your doctor may consider an increase in dosage from 2.5 to 5mg if ineffective. Side effects of Cialis include headache and indigestion.

Viagra is taken on an as-needed basis, at a dose of 50mg, approximately 1 hour before sexual activity (although can be taken from 30 minutes to 4 hours before). The dose may be increased to 100mg if 50mg is ineffective or decreased to 25mg if side effects are intolerable. Viagra should only be taken once a day even though the effects wear off after approximately 4-5 hours. The main side effects are headache, flushing, and indigestion. Rarely, color perception may be altered with Viagra. This side effect does not happen with Cialis.

3 The difference in lasts time

On March 27 th, 1998, Viagra became the first oral pill, and the first PDE5 inhibitor, to be approved by the FDA to treat ED.4 A generic for Viagra was approved in March 2016 5 and released in December 2017.

Cialis was first approved for ED on November 21st, 2003.6 It was the third PDE5 inhibitor to come onto the market (after Levitra [vardenafil]).7 Cialis has an advantage over Viagra and Levitra in that it lasts for a lot longer – 36 hours, compared with 4-5 hours for Viagra and Levitra.1,2,7 A generic for Cialis was approved in May 2018 11 and released in September 2018.