Viagra, also known by its generic name Sildenafil, is a medication primarily used to treat erectile dysfunction (ED). It falls under a class of drugs known as phosphodiesterase type 5 (PDE5) inhibitors¹. Here's a summary of its uses and important details:

Uses

1. Erectile Dysfunction (ED): Viagra helps by increasing blood flow to the penis during sexual stimulation, which assists in achieving and maintaining an erection¹. It generally takes about 30 to 60 minutes to start working and can be taken up to four hours before sexual activity².
2. Pulmonary Arterial Hypertension (PAH): Sildenafil, under different brand names like Revatio, is also used to treat PAH, which involves high blood pressure in the vessels that supply the lungs. It works by relaxing blood vessels in the chest, thereby reducing blood pressure and improving the ability to exercise².

Dosage

• For Erectile Dysfunction: The typical starting dose is 50 mg, taken as needed about one hour before sexual activity. Based on effectiveness and tolerance, the dose may be adjusted to 100 mg or reduced to 25 mg³.
• For Pulmonary Arterial Hypertension: Generally taken three times a day, the dosage and specific instructions should follow a healthcare provider’s direction⁴.

Important Details

• Side Effects: Common side effects include headaches, feeling sick, indigestion, and dizziness⁵.
• Interactions: It is crucial not to take Viagra with nitrates (often prescribed for chest pain) as this can lead to a dangerous drop in blood pressure. Additionally, grapefruit juice should be avoided as it can affect how the medication works².
• Sexual Excitation Needed: Sildenafil alone won’t cause an erection; sexual stimulation is required for the drug to be effective³.

Safety and Precautions

• Existing health conditions and concurrent medications should be discussed with a healthcare provider before using Viagra to avoid potential interactions and side effects⁴.
• Viagra does not offer protection against sexually transmitted infections (STIs) and does not increase sexual desire¹.

For more comprehensive information, you can visit NHS's Sildenafil (Viagra) page or MedlinePlus.

Footnotes

1. NHS, "Sildenafil (Viagra): medicine for erection problems," April 2024, NHS. ↩ ↩² ↩³

2. NHS, "About sildenafil (Viagra)," March 2022, NHS. ↩ ↩² ↩³

3. NHS, "How and when to take sildenafil," March 2022, NHS. ↩ ↩²

4. MedlinePlus, "Sildenafil: MedlinePlus Drug Information," MedlinePlus. ↩ ↩²

5. Mayo Clinic, "What to know about oral meds for erectile dysfunction," June 2023, Mayo Clinic. ↩