When starting sildenafil (Viagra) for erectile dysfunction, when should I schedule the follow‑up visit?

When to Schedule Follow-Up After Starting Sildenafil (Viagra)

Schedule the first follow-up visit 4–6 weeks after initiating sildenafil to assess efficacy, tolerability, and address any modifiable factors that may be limiting response. 1

Rationale for 4–6 Week Timing

• Sildenafil is a fast-onset PDE5 inhibitor (works within 1 hour), so unlike 5-alpha reductase inhibitors that require 3–6 months, response can be evaluated much earlier. 1
• The UK guidelines explicitly recommend follow-up between 4 weeks and 6 months for erectile dysfunction treatments, with earlier review appropriate for faster-acting agents like sildenafil. 1
• This timeframe allows the patient to complete an adequate trial (at least 5 separate attempts at the prescribed dose) before declaring treatment success or failure. 2

What to Assess at the 4–6 Week Follow-Up

Efficacy Evaluation

• Use the International Index of Erectile Function (IIEF) or similar validated questionnaire to objectively measure improvement. 1
• Ask about successful intercourse attempts: Clinical trials show 69% success with sildenafil versus 35.5% with placebo, so most responders will report improvement by this point. 2, 3
• Verify the patient has made at least 5 attempts at the current dose with proper technique before concluding the medication is ineffective. 2

Tolerability and Adverse Effects

• Screen for common side effects: headache (most frequent), flushing, dyspepsia, nasal congestion, and abnormal vision. 2, 3
• Most adverse events are mild-to-moderate and transient, but if intolerable, dose reduction or switching agents may be warranted. 2
• Discontinuation rates due to adverse events are low (≈2%), so most patients tolerate sildenafil well. 4

Modifiable Factors That Limit Response

Before escalating the dose or declaring treatment failure, systematically evaluate:

• Sexual stimulation: PDE5 inhibitors require arousal to work—this is the most common reason for apparent "failure." 2, 3
• Timing and food intake: Taking sildenafil with large or fatty meals significantly reduces efficacy. 2
• Alcohol use: Heavy alcohol consumption impairs erectile function independent of medication. 2
• Relationship issues: Psychological factors and partner conflict significantly impact response. 2
• Concomitant medications: Identify drugs that worsen ED (antihypertensives, antidepressants, opioids) or interact with sildenafil (CYP3A4 inhibitors). 2
• Hormonal status: Check testosterone levels if response is suboptimal—men with testosterone deficiency respond less robustly to PDE5 inhibitors alone. 2

Dose Titration Strategy at Follow-Up

• If 50 mg is inadequate but well-tolerated, increase to 100 mg (maximum dose) after confirming the patient has completed at least 5 attempts and addressed modifiable factors. 2, 3
• If 50 mg causes intolerable side effects, reduce to 25 mg. 2, 3
• The American Urological Association strongly recommends dose titration to optimize the balance between efficacy and tolerability. 2

When to Schedule Subsequent Follow-Up

• If treatment is successful and well-tolerated, arrange ongoing prescribing with periodic reassessment (every 6–12 months) to verify cardiovascular health stability, new medications, and continued efficacy. 1, 2
• If treatment fails at maximum dose (100 mg) after at least 5 attempts, consider switching to a different PDE5 inhibitor (tadalafil or vardenafil) or referring for second-line therapies. 2

Critical Safety Reminders at Every Visit

• Re-verify no nitrate use (organic nitrates, glyceryl trinitrate, isosorbide dinitrate)—this is an absolute contraindication due to potentially fatal hypotension. 2, 3
• Reassess cardiovascular risk: If the patient cannot perform moderate physical activity (walk 1 mile in 20 minutes or climb 2 flights of stairs), refer to cardiology before continuing treatment. 2
• Educate on emergency nitrate protocol: Wait at least 24 hours after sildenafil before administering nitrates under close medical supervision. 2

Common Pitfalls to Avoid

• Declaring treatment failure too early: Many "non-responders" are actually using the medication incorrectly (lack of sexual stimulation, improper timing, taking with food). 2
• Failing to address modifiable factors: Up to 30% of apparent non-responders become successful after re-education on proper use and correction of modifiable factors. 2
• Not completing an adequate trial: At least 5 separate attempts at the prescribed dose are required before concluding the medication is ineffective. 2