From the Guidelines
The recommended starting dose of sildenafil (Viagra) for erectile dysfunction is 50 mg taken approximately one hour before sexual activity, with a maximum frequency of once daily. This dose may be adjusted based on effectiveness and tolerability, ranging from 25 mg to 100 mg, as supported by the American College of Physicians guideline 1. For older patients (over 65), those with hepatic or severe renal impairment, or patients taking certain medications like CYP3A4 inhibitors, a lower starting dose of 25 mg is recommended. Sildenafil works by inhibiting phosphodiesterase type 5 (PDE5), which increases blood flow to the penis during sexual stimulation. The medication should be taken with water on an empty stomach for optimal absorption, as high-fat meals can delay its onset of action. Patients should be aware that sildenafil requires sexual stimulation to work and typically remains effective for about 4-5 hours. Common side effects include headache, flushing, indigestion, and nasal congestion. Sildenafil should not be taken with nitrates or nitric oxide donors due to the risk of dangerous drops in blood pressure, as highlighted in the guideline 1.
Some key points to consider when prescribing sildenafil include:
- The dose may need to be adjusted based on individual patient response and tolerability, as noted in the study 1.
- Patients should be counseled on the potential side effects and interactions with other medications, such as nitrates and CYP3A4 inhibitors, as discussed in the guideline 1.
- Sildenafil is effective for improving erectile function and successful sexual intercourse, as demonstrated in the clinical practice guideline from the American College of Physicians 1.
It's also important to note that the American College of Physicians recommends that clinicians initiate therapy with a PDE-5 inhibitor, such as sildenafil, in men who seek treatment for erectile dysfunction and who do not have a contraindication to PDE-5 inhibitor use, as stated in the guideline 1. The choice of a specific PDE-5 inhibitor should be based on individual patient preferences, including ease of use, cost of medication, and adverse effects profile, as recommended in the guideline 1.
From the FDA Drug Label
Inform patients that sildenafil is also marketed as sildenafil citrate tablets, 25 mg, 50 mg and 100 mg for erectile dysfunction. The recommended strength and dose of sildenafil for erectile dysfunction is:
- 25 mg
- 50 mg
- 100 mg 2
From the Research
Sildenafil Dosage for Erectile Dysfunction
- The recommended starting dose of sildenafil for erectile dysfunction is 50 mg, taken 1 hour before sexual activity, with subsequent adjustment to 100 or 25 mg based on efficacy and safety 3.
- Most men are later titrated to sildenafil 100 mg for improved efficacy 4.
- Sildenafil 100 mg has been shown to be effective in men with erectile dysfunction, with improved erections reported by 84% of men taking this dose 5.
- The efficacy and safety of sildenafil have been assessed in various age subgroups, including men under 65-74, and 75 years or older, with statistically significant improvements in erectile function and overall satisfaction reported for all age subgroups 3.
Strength and Dose
- The strength and dose of sildenafil indicated for erectile dysfunction are 50 mg and 100 mg, with the 100 mg dose being more effective for some men 5, 4.
- The dose of sildenafil can be adjusted based on individual response and tolerability, with a maximum recommended dose of 100 mg per day 3.
- Sildenafil is available in various formulations, including tablets and oral suspensions, with the same recommended dosing regimen 6.
Efficacy and Safety
- Sildenafil has been shown to be an effective and well-tolerated treatment for erectile dysfunction, with a high success rate and minimal adverse effects 5, 4, 3, 7, 6.
- The most common adverse effects of sildenafil are headache, flushing, and dyspepsia, which are generally mild and transient 5, 3.
- Sildenafil is contraindicated in men taking nitrates or nitric oxide donors, and should be used with caution in men with certain medical conditions, such as coronary artery disease or benign prostatic hyperplasia 5, 7.