What is the recommended starting dose of sildenafil (Viagra) for male erectile dysfunction?

Best Starting Dosage of Sildenafil for Male Erectile Dysfunction

The recommended starting dose of sildenafil for erectile dysfunction is 50 mg, taken approximately 1 hour before sexual activity, with subsequent titration to 100 mg if inadequate or reduction to 25 mg based on tolerability. 1

Standard Dosing Protocol

• Start with 50 mg as the initial dose for most men with erectile dysfunction 1
• Take approximately 1 hour before anticipated sexual activity, but not more than once daily 1, 2
• Sexual stimulation is mandatory for the medication to work—this is a critical point that must be emphasized to patients 1, 3

Dose Titration Strategy

• If 50 mg is inadequate after proper use, increase to 100 mg (the maximum recommended dose) 1
• If side effects are problematic at 50 mg, reduce to 25 mg 1, 2
• The dose-response relationship shows that 50 mg is superior to 25 mg, though the incremental benefit from 50 mg to 100 mg is less pronounced 3
• Before declaring treatment failure, ensure at least 5 separate attempts at the maximum dose (100 mg) 1

Special Populations Requiring Lower Starting Dose (25 mg)

The following patients should start at 25 mg rather than 50 mg 1:

• Severe hepatic impairment (though severe hepatic disease is generally a contraindication)
• Renal impairment
• Concurrent use of CYP3A4 inhibitors, including:
  • Ritonavir or saquinavir
  • Ketoconazole
  • Erythromycin
  • Cimetidine
• Elderly patients may also benefit from starting at 25 mg 2

Critical Safety Contraindications

• Absolute contraindication: concurrent nitrate use (organic nitrates, glyceryl trinitrate, isosorbide dinitrate) due to severe hypotension risk 1
• Wait at least 24 hours after sildenafil before administering nitrates in emergency situations 1, 3
• High-risk cardiovascular conditions requiring cardiac stabilization before treatment include 1:
  • Unstable or refractory angina
  • Uncontrolled hypertension
  • Recent MI or stroke (within 2 weeks)
  • Severe heart failure (NYHA class II or higher)

Common Pitfalls Leading to "Treatment Failure"

Many apparent treatment failures result from incorrect usage rather than true medication ineffectiveness 1:

• Lack of adequate sexual stimulation (the drug requires sexual arousal to work)
• Taking with large meals, which delays absorption 1
• Improper timing of the dose relative to sexual activity
• Heavy alcohol use, which impairs erectile function 1
• Inadequate trial: fewer than 5 attempts at maximum dose 1

Expected Efficacy

• Success rates: 69% of men achieve successful sexual intercourse attempts with sildenafil vs 35.5% with placebo 1
• 73-88% report improvement in erections vs 26-32% with placebo 1, 3
• Efficacy is maintained across various etiologies including diabetes, cardiovascular disease, depression, spinal cord injury, and post-prostatectomy, though men with diabetes and post-prostatectomy patients may respond less robustly 1, 4

Common Adverse Effects

The most frequent side effects are transient and mild-to-moderate 1, 3:

• Headache
• Flushing
• Dyspepsia
• Nasal congestion
• Abnormal vision

Follow-Up and Ongoing Management

• Periodic follow-up should assess efficacy, side effects, and changes in cardiovascular health or new medications 1
• Before switching to a different PDE5 inhibitor, verify that the trial was adequate by addressing modifiable factors 1
• Re-educate patients on proper use if initial attempts are unsuccessful 1