Alpha-adrenoceptor Blockers


 

Alfuzosin, Doxazosin, Indoramin, Prazosin, Tamsulosin, Terazosin


  Issues for Surgery


For treatment of hypertension – loss of blood pressure (BP) control if omitted.

For benign prostatic hyperplasia – risk of acute urinary retention if omitted.

Risk of hypotension when continued, particularly with alfuzosin (see Interaction(s) with Common Anaesthetic Agents)

Risk of Intraoperative Floppy Iris Syndrome (IFIS) in patients undergoing cataract surgery when continued (see Further Information).


  Advice in the Perioperative period


Elective and Emergency Surgery 

Continue, including combination product – monitor BP.

Combination product:

  • Tamsulosin with dutasteride (also see 5-α Reductase Inhibitors monograph)

Patients undergoing Cataract Surgery 
Ensure the Ophthalmologist / Cataract Surgeon is aware the patient is taking an alpha-adrenoceptor blocker (see Further Information).

Post-operative Advice

Patients undergoing Transurethral Resection of Prostate (TURP)
If indicated for the treatment of Benign Prostatic Hyperplasia (BPH), alpha-adrenoceptor blockers may be stopped following an effectual TURP, subject to a successful Trial Without Catheter (TWOC).


  Interaction(s) with Common Anaesthetic Agents

 

Hypotension

Alpha-adrenoceptor blockers can increase the risk of hypotension when used concomitantly with inhalational or intravenous anaesthetics1.

The manufacturer of alfuzosin advises withhold 24 hours prior to surgery2, 3.  However, in practice alfuzosin is continued – monitor BP.


  Interaction(s) with other Common Medicines used in the Perioperative Period

 

Hypotension

Alpha-adrenoceptor blockers can increase the risk of hypotension when used concomitantly with droperidol or prochlorperazine1.


  Further Information


Intraoperative Floppy Iris Syndrome (IFIS)

IFIS has been observed during cataract surgery in some patients on or previously treated with tamsulosin. Isolated reports have also been received with other alpha-adrenoceptor blockers and the possibility of a class effect cannot be excluded.  As IFIS may lead to increased procedural complications during the cataract operation current or past use of alpha-adrenoceptor blockers should be made known to the Ophthalmic Surgeon in advance of surgery1, 3, 4, 5, 6, 7, 8.

 

  References


  1. Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 18th March 2019]
  2. Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 18th March 2019]
  3. Summary of Product Characteristics – Alfuzosin Hydrochloride 2.5mg Tablets. Zentiva. Accessed via www.medicines.org.uk 18/03/2019 [date of revision of the text August 2018]
  4. Summary of Product Characteristics - Cardura® (doxazosin) Tablets 2mg. Pfizer Limited. Accessed via www.medicines.org.uk 18/03/2019 [date of revision of the text February 2019]
  5. Summary of Product Characteristics - Hypovase® (prazosin) 1mg Tablets. Bayer plc. Accessed via www.medicines.org.uk 18/03/2019 [date of revision of the text August 2018]
  6. Summary of Product Characteristics – Contiflo® XL (tamsulosin) 400 micrograms prolonged release capsules. Ranbaxy (UK) Limited a Sun Pharmaceutical Company. Accessed via www.medicines.org.uk 18/03/2019 [date of revision of the text April 2017]
  7. Summary of Product Characteristics – Hytrin® (terazosin) Tablets 10mg. ADVANZ Pharma. Accessed via www.medicines.org.uk 18/03/2019 [date of revision of the text October 2018]
  8. Summary of Product Characteristics – Doralese® (indoramin) Tiltab Tablets 20mg. Chemidex Pharma Ltd. Accessed via www.medicines.org.uk 09/04/2019 [date of revision of the text December 2015]