4.10 Alpha-1 Antagonists

Tamsulosin is an Alpha-1 antagonist.

Mechanism of Action:  Tamsulosin selectively blocks alpha receptors in the prostate, leading to the relaxation of smooth muscles in the bladder, neck, and prostate, thus improving urine flow and reducing symptoms of benign prostatic hypertrophy (BPH).

Indications for Use: Tamsulosin is used to treat BPH.

Nursing Considerations Across the Lifespan: Alpha-1 antagonists are not recommended for children under the age of 2 years old.  They are safe to use in older adults, but dose adjustments need to be made based on kidney function.  There is limited information about whether alpha-1 antagonists, such as tamsulosin, can be used in pregnancy.

Avoid using with other alpha-blockers. Tamsulosin is contraindicated with strong CYP3A4 inhibitors such as ketoconazole. Assess and monitor blood pressure, especially after first dose because tamsulosin may cause orthostatic hypotension.

Patient Teaching & Education: Advise clients to change positions slowly because the drug may cause orthostatic blood pressure changes.  Additionally, the client should take the medication at the same time each day.  The client should follow up with their healthcare provider to assess the effectiveness of the medication.^[1]

Now let’s take a closer look at the medication grid on tamsulosin in Table 4.10.^[2][3] Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.

Table 4.10 Tamsulosin Medication Card