Medicines & Supplements A to Z > Doxazosin


Last updated on 12/07/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  



BRAND NAME(S) IN HONG KONG: Cardura 確得迅®, Cardura XL 確得迅®

DRUG CLASS: Antihypertensives, Vasodilators

SUB CLASS: Alpha blockers

USED FOR: High blood pressure, benign prostatic hyperplasia

– 1 mg, 2 mg, 4 mg (tablets)
– 4 mg, 8 mg (controlled-release tablets)

What is Doxazosin for?

Doxazosin belongs to a class of medications called alpha blockers. It is used to treat high blood pressure and benign prostatic hyperplasia.

How to use it?

Doxazosin can be taken by mouth, with or without food.

High blood pressure, Benign prostatic hyperplasia
Immediate-release tablets: Initially 1 mg once daily for 1-2 weeks, then increase to 2 mg once daily, then increase if necessary to 4 mg once daily. Maximum dosage is 16 mg per day.
Modified-release tablets: Initially 4 mg once daily, dose can be adjusted after 4 weeks, then increase if necessary to 8 mg once daily.

What are the side effects of Doxazosin?

Common side effects of Doxazosin include dizziness and drowsiness, dry mouth, dyspnoea, gastrointestinal discomfort, headache, nausea, vertigo, oedema, and pain.

Who should not take Doxazosin?

– People allergic to Doxazosin or any component of the formulation.
– Patients with urinary tract obstruction, urinary tract infection or bladder stones.
– Patients with a history of postural hypotension.

Pharmacist Tips:

This medication can make you dizzy. Avoid driving or operating machinery until you know how you respond to Doxazosin.

Common dosing schedule:
Doxazosin is usually taken once daily. For the initial dose of a modified-release tablet, take with breakfast.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Doxazosin may interact with:
– Phosphodiesterase inhibitors, e.g. Sildenafil, Tadalafil, Vardenafil
– Diuretics, e.g. Furosemide, Hydrochlorothiazide
– Sympathomimetics, e.g. Epinephrine, Norepinephrine, Pseudoephedrine
– Other antihypertensive medications

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Doxazosin in Hong Kong?

In Hong Kong, Doxazosin is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Doxazosin in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.