Tamsulosin (Flomax) Dosage Information
No, Flomax (tamsulosin) does not come in a 0.2 mg tablet in the United States. Tamsulosin is typically available in 0.4 mg capsules or tablets in the U.S. market as the standard dosage form.
Available Dosage Forms
- Standard U.S. formulation: 0.4 mg modified-release capsules/tablets
- International variations: In some countries, particularly in Asia, a lower 0.2 mg dose is available 1
- Formulation types:
- Modified-release (MR) formulation
- Oral controlled absorption system (OCAS) formulation (available in some countries) 2
Clinical Dosing Information
Standard Dosing
- The recommended starting and maintenance dose for tamsulosin in the U.S. is 0.4 mg once daily 1, 3
- Tamsulosin should be taken approximately 30 minutes after the same meal each day
- Unlike other alpha-blockers, tamsulosin does not require dose titration when initiating treatment 3
International Dosing Variations
- In Japan and some Asian countries, daily doses of 0.1-0.4 mg have been studied and are available 3
- Korean studies have evaluated tamsulosin at the 0.2 mg dose 4
Pharmacological Considerations
- Tamsulosin is a selective alpha-1A and alpha-1D adrenoceptor antagonist that targets receptors in the prostate gland, prostatic capsule, prostatic urethra, and bladder 1
- The oral bioavailability of the modified-release formulation is close to 100% in the fasted state 2
- Food affects absorption of the MR formulation but not the OCAS formulation 2
Clinical Efficacy
- Tamsulosin 0.4 mg once daily significantly improves urinary symptoms and flow rates compared to placebo 5
- Efficacy is dose-related up to a ceiling dose of 0.4 mg 3
- Tamsulosin provides similar efficacy to other alpha-blockers but with fewer cardiovascular side effects 1, 6
Common Pitfalls and Considerations
- Medication splitting: Do not split, crush, or chew tamsulosin capsules as this will affect the modified-release properties
- Cardiovascular effects: Unlike non-selective alpha-blockers, tamsulosin has minimal effects on blood pressure at therapeutic doses 3
- Surgical considerations: Patients taking tamsulosin who undergo cataract surgery are at increased risk for intraoperative floppy iris syndrome 4
- Sexual side effects: Ejaculatory dysfunction is more common with tamsulosin than with other alpha-blockers 4
If a lower dose than 0.4 mg is needed, patients should consult with their healthcare provider about alternative medications or treatment approaches, as pill-splitting is not recommended for modified-release formulations of tamsulosin.