Can tadalafil (phosphodiesterase type 5 inhibitor) be taken every day at a 20 mg dose?

Tadalafil 20mg Daily Dosing Safety and Efficacy

Tadalafil should not be taken at the 20mg dose on a daily basis as this exceeds the FDA-approved dosing regimen for daily use, which is limited to 2.5-5mg daily.

Approved Dosing Regimens for Tadalafil

Tadalafil has two distinct dosing regimens that are FDA-approved:

1. As-needed dosing:

   • 10-20mg taken prior to anticipated sexual activity
   • Maximum recommended frequency: once per day
   • Effective for up to 36 hours after dosing 1

2. Once-daily dosing:

   • 2.5-5mg taken at approximately the same time every day
   • For erectile dysfunction: Start with 2.5mg, may increase to 5mg based on efficacy and tolerability
   • For BPH or combined ED/BPH: 5mg daily 1

Safety Concerns with 20mg Daily Dosing

Taking tadalafil 20mg daily would result in:

• Excessive drug accumulation due to tadalafil's long half-life (17.5 hours) 2
• Increased risk of adverse effects including:
  • Headache
  • Dyspepsia (indigestion)
  • Back pain
  • Myalgia (muscle pain)
  • Flushing
  • Nasal congestion 1

Evidence Supporting Approved Dosing

• Clinical trials specifically evaluated tadalafil at 2.5mg and 5mg for daily dosing, not 20mg 3
• Long-term safety studies for daily dosing were conducted using the 5mg dose, not higher doses 4
• The 20mg dose was only studied and approved for as-needed use 1

Erectile Dysfunction Treatment Options

For patients seeking daily treatment for ED:

1. First-line: Tadalafil 2.5-5mg daily, which has demonstrated:

   • Significant improvement in erectile function
   • Maintenance of efficacy for up to 2 years
   • Good tolerability profile 4
   • Elimination of the need to time medication with sexual activity

2. Alternative approach: As-needed tadalafil 10-20mg, which:

   • Can be effective within 16-30 minutes of dosing 5
   • Provides efficacy for up to 36 hours
   • Is appropriate for patients who prefer not to take daily medication

Special Considerations

For patients who have not achieved normal erectile function with as-needed PDE5 inhibitors:

• Switching to daily tadalafil 5mg may help restore normal erectile function in approximately 40% of cases 6

Bottom Line

The 20mg dose of tadalafil is only approved for as-needed use, not daily administration. Patients requiring daily treatment should use the approved 2.5-5mg daily doses, which provide effective treatment with a better safety profile.