Which is better for an elderly male patient with a pacemaker, hypertension, BPH, and erectile dysfunction, finasteride and tadalafil combination or dutasteride and tadalafil combination?

Dutasteride Plus Tadalafil Combination is Superior to Finasteride Plus Tadalafil

For an elderly male patient with a pacemaker, hypertension, BPH, and erectile dysfunction, the combination of dutasteride 0.5 mg and tadalafil 5 mg daily is the preferred regimen over finasteride plus tadalafil, based on dutasteride's more potent DHT suppression (95% vs 70%) and equivalent safety profile, with both combinations providing dual benefits for BPH symptoms and erectile function. 1, 2

Mechanism and Efficacy Comparison

Dutasteride's Superior Pharmacologic Profile

• Dutasteride inhibits both type I and type II 5-alpha-reductase isoenzymes, reducing serum DHT by approximately 95%, compared to finasteride's 70% reduction through type II inhibition alone 1
• This translates to a 15-25% reduction in prostate volume after 6 months with both agents, but dutasteride achieves more complete DHT suppression 3, 1
• Both agents provide 3-4 point improvements in symptom scores maintained for 6-10 years 3, 1

Clinical Outcomes with 5-ARI Plus Tadalafil Combinations

• The combination of tadalafil 5 mg with finasteride significantly improves both LUTS (measured by IPSS) and erectile function (measured by IIEF-EF domain scores) compared to finasteride plus placebo 2
• In sexually active men with baseline ED, tadalafil/finasteride achieved minimal clinically important differences (≥4-point IIEF-EF improvement) at significantly higher rates than placebo/finasteride at 4,12, and 26 weeks (P < 0.001) 2
• The AUA guidelines state that dutasteride has similar efficacy to finasteride in terms of symptom improvement and disease progression prevention, with comparable safety profiles 3

Specific Advantages for This Patient Population

Cardiovascular Safety Considerations

• Tadalafil 5 mg is contraindicated in patients with poorly controlled blood pressure, but can be used cautiously in patients with controlled hypertension 4
• The patient's pacemaker is not a contraindication to tadalafil, but the medication is contraindicated in those using nitrates or guanylate cyclase stimulators 4
• Tadalafil frequently causes flushing, gastro-oesophageal reflux, headache, dyspepsia, back pain, and nasal congestion 4
• Neither dutasteride nor finasteride has direct cardiovascular effects and does not interfere with antihypertensive medications 3

Dual Benefit for BPH and ED

• Tadalafil 5 mg is the only PDE5 inhibitor licensed for treatment of male LUTS, providing modest IPSS reduction (-1.74 points vs placebo) and improvements in erectile function 4
• The combination addresses both conditions simultaneously, which is particularly relevant for elderly patients with multiple comorbidities 2, 5
• Sexual dysfunction adverse events were low with tadalafil/finasteride: only 5 patients on combination therapy vs 7 on placebo/finasteride reported sexual AEs 2

Treatment Protocol

Recommended Regimen

1. Initiate dutasteride 0.5 mg once daily plus tadalafil 5 mg once daily 1
2. Counsel that 5-ARI effects take 3-6 months to become apparent, with maximum benefit at 6-12 months 3
3. Tadalafil provides more immediate symptom relief for both LUTS and ED 5, 6

Monitoring Requirements

• PSA levels decrease by approximately 50% after 1 year of 5-ARI therapy; double the measured PSA value after 1 year for accurate prostate cancer screening interpretation 3, 1
• Reassess IPSS and erectile function at 4-6 weeks and 3 months 4
• Monitor blood pressure given tadalafil use in context of hypertension 4

Critical Safety Considerations

Sexual Side Effects

• Decreased libido occurs in 6.4% of patients in the first year with 5-ARIs (decreases to 2.6% in years 2-4) 3
• Ejaculatory dysfunction occurs in 3.7% in the first year (decreases to 1.5% in years 2-4) 3
• These side effects are typically reversible and become less common after the first year 3, 7

Tadalafil-Specific Warnings

• Patients must seek emergency medical attention for erections lasting >4 hours 8
• Stop tadalafil immediately and seek medical attention for sudden vision loss (NAION risk) or sudden hearing loss 8
• Avoid substantial alcohol consumption (≥5 units) with tadalafil due to additive vasodilatory effects causing orthostatic symptoms 8

Why Not Finasteride Plus Tadalafil?

While finasteride plus tadalafil is effective 2, 9, dutasteride offers:

• More complete DHT suppression (95% vs 70%) 1
• Equivalent clinical efficacy with similar safety profile per AUA guidelines 3
• The AUA specifically states dutasteride and finasteride have comparable efficacy and safety, making dutasteride's superior pharmacologic profile the deciding factor 3

Common Pitfalls to Avoid

• Do not use this combination in patients without prostatic enlargement (prostate volume <30cc), as 5-ARIs are ineffective 3, 1
• Do not combine tadalafil with alpha-blockers, as the AUA states this offers no advantages in symptom improvement over either agent alone 4
• Do not fail to adjust PSA interpretation (doubling after 1 year) which can lead to delayed cancer diagnosis 3, 1
• Do not prescribe tadalafil to patients on nitrates or with recent stroke (<6 months) 4
• Do not expect immediate 5-ARI effects; counsel patients that symptom improvement takes 3-6 months 3