What is the difference between Flomax (tamsulosin) and Flomax CR (controlled-release tamsulosin) for treating benign prostatic hyperplasia (BPH)?

Flomax vs. Flomax CR for Benign Prostatic Hyperplasia

Flomax CR (controlled-release tamsulosin) offers no significant clinical advantage over standard Flomax (tamsulosin) for BPH treatment, as both formulations contain the same active ingredient and provide similar efficacy in reducing lower urinary tract symptoms. 1, 2

Similarities Between Formulations

• Both formulations contain tamsulosin, an alpha1A and alpha1D-adrenoceptor antagonist that relaxes prostate and bladder smooth muscles to improve urinary flow 3
• Both are indicated for treatment of signs and symptoms of benign prostatic hyperplasia (BPH) 2
• Neither formulation is indicated for the treatment of hypertension 2
• Both work by the same mechanism - selectively blocking alpha1A receptors that predominate in the prostate gland, prostatic capsule, prostatic urethra and bladder 3

Efficacy Profile

• Tamsulosin in either formulation provides similar clinical benefits:
  • Improves International Prostate Symptom Score (IPSS) by approximately 35% after 4 weeks and 55% after 12 weeks 4
  • Increases maximum urinary flow rate (Qmax) by approximately 1.1 mL/sec compared to placebo 5
  • Improves quality of life scores by about 45% after 4 weeks and 69% after 12 weeks 4

Administration Considerations

• Standard Flomax: 0.4 mg once daily, taken approximately 30 minutes after the same meal each day 2
• Both formulations should not be crushed, chewed, or opened 2
• Neither formulation requires dose titration at initiation of therapy, unlike non-selective alpha blockers 6

Safety Profile

• Both formulations have similar side effect profiles:
  • Most common adverse effects include dizziness, rhinitis, and abnormal ejaculation 5
  • Ejaculatory dysfunction occurs in approximately 8-18% of patients 1
  • Low potential for orthostatic hypotension compared to non-selective alpha blockers 1, 6
  • Risk of intraoperative floppy iris syndrome during cataract surgery 1, 2

Clinical Considerations and Pitfalls

• Important precautions for both formulations:

  • Patients undergoing cataract surgery should inform their ophthalmologist about tamsulosin use due to risk of intraoperative floppy iris syndrome 1
  • Neither formulation should be combined with other alpha blockers due to increased risk of adverse effects 1
  • Both formulations have minimal impact on blood pressure when used at recommended doses 3, 6

• Common pitfalls to avoid:

  • Failing to counsel patients about potential ejaculatory dysfunction, which can affect up to 18% of users 1
  • Missing the need to take with food consistently (approximately 30 minutes after the same meal each day) 2
  • Overlooking potential drug interactions with other antihypertensive medications 2

Conclusion

When choosing between Flomax and Flomax CR for BPH management, either formulation provides similar efficacy and safety profiles. The decision should be based on medication availability, cost considerations, and insurance coverage rather than expected differences in clinical outcomes.