4.9 Alpha-1 Antagonists

Open Resources for Nursing (Open RN)

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: Tamsulosin is used to treat BPH.

Nursing Considerations: 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 patients to change positions slowly because the drug may cause orthostatic blood pressure changes.  Additionally, the patient should take the medication at the same time each day.  The patient 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 4.9.[2]

Table 4.9 Tamsulosin Medication Grid

Administration Considerations
Therapeutic Effects
Side/Adverse Effects
Alpha-1 antagonist tamsulosin Avoid using with other alpha- blockers

Assess and monitor blood pressure, especially after first dose

Relaxes smooth muscle in bladder/prostate to improve urine flow Hypotension, especially after first dose. Advise patient to change positions slowly


  1. uCentral from Unbound Medicine. https://www.unboundmedicine.com/ucentral
  2. This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain.


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