From the Guidelines
I strongly advise against prescribing Viagra 20mg every 3 days without a proper medical evaluation by a qualified healthcare provider. Viagra typically comes in 25mg, 50mg, and 100mg tablets for erectile dysfunction, not 20mg (though sildenafil for pulmonary hypertension does come in 20mg) 1. Medication prescriptions require proper medical evaluation by a qualified healthcare provider who can assess your medical history, current medications, and potential contraindications. According to the American Urological Association guideline, men with ED should be informed regarding the treatment option of an FDA-approved oral phosphodiesterase type 5 inhibitor (PDE5i), including discussion of benefits and risks/burdens, unless contraindicated 1.
Key Considerations
- The dose of PDE5i should be titrated to provide optimal efficacy, and instructions should be provided to maximize benefit/efficacy 1.
- The most frequently reported adverse events (AEs) in men using PDE5i are dyspepsia, headache, flushing, back pain, nasal congestion, myalgia, visual disturbance, and dizziness 1.
- Viagra can interact dangerously with nitrates and certain other medications, potentially causing severe drops in blood pressure.
Recommendations
- Please consult with a physician or other licensed healthcare provider who can properly evaluate your needs, prescribe an appropriate medication regimen, and monitor for side effects or complications.
- The choice of a specific PDE-5 inhibitor should be based on the individual preferences of men with erectile dysfunction, including ease of use, cost of medication, and adverse effects profile 1.
From the Research
Dosage and Administration of Viagra
- The recommended single-dose range for Viagra is 25-100 mg 2.
- There is no specific mention of a 20 mg dose in the provided studies.
- The frequency of administration is not explicitly stated in the studies, but it is mentioned that Viagra is taken one hour prior to sexual activity 3.
Safety and Contraindications
- Viagra is contraindicated in patients on organic nitrates, as this combination can lead to severe drops in blood pressure 3, 2.
- Patients with heart disease, suspected heart disease, and risk factors for heart disease should discuss with their physicians the safety of resuming sexual activity 3.
- The use of Viagra necessitates caution in cardiac failure and when used within six months of acute myocardial infarction and stroke 2.
Efficacy and Comparison with Other PDE5 Inhibitors
- Sildenafil (Viagra) is effective in improving erectile function in men with erectile dysfunction, including those with diabetes and prostate cancer 4.
- Tadalafil may be preferred over sildenafil due to its longer duration of action 4.
- A network meta-analysis found that tadalafil was associated with the highest efficacy in treating erectile dysfunction in men with spinal cord injury, followed by vardenafil and sildenafil 5.