Who should not take Viagra and why? What happens if you take viagra?

Viagra is used to treat erectile dysfunction. It works by relaxing the blood vessels and increasing blood flow, helping you achieve an erection.

The  Erectile Dysfunction Calculator is an advanced and technical tool for assessing ED.

But does Viagra work the first time?

Usually, Viagra works the first time for most people, but that's not always the case. Here are some reasons why it might not work:

Wrong Dosage: Viagra comes in 25mg, 50mg, and 100mg doses. You might need a different dose than what was prescribed. Talk to your doctor to adjust the dose if you don't see results.

Stress or Anxiety: Feeling nervous or stressed about your sexual performance can affect Viagra's effectiveness.

Mental Health Issues: Conditions like depression, anxiety, or stress can also prevent Viagra from working.

Lack of Mood or Attraction: Viagra helps with erections but doesn’t affect your mood or attraction. If you're not in the mood or don’t feel attracted to your partner, it might not work.

If you’re stressed, try to manage it first and get in a comfortable state before retaking Viagra. If it still doesn’t work, consult your doctor for advice on adjusting the dose or changing the medication.

source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2699643/

             https://www.nhs.uk/medicines/sildenafil-viagra/how-and-when-to-take-sildenafil/