Doxazosin
Brand name Cardura
Used in the following combined preparations None
General Information
Doxazosin is an antihypertensive vasodilator drug that relieves hypertension (high blood pressure) by relaxing the muscles in the blood vessel walls, which dilates them and thereby eases the flow of blood. As doxazosin is eliminated slowly from the body, it is usually given only once daily. It may be administered together with other antihypertensive drugs, including beta blockers, since its effects on blood pressure are increased when it is combined with most other antihypertensives.
Given in low doses, doxazosin is also used to relieve symptoms caused by an enlarged prostate gland.
Dizziness and fainting may occur at the onset of treatment with doxazosin, because the first dose may cause a marked fall in blood pressure. For this reason, the initial dose is usually low.
Quick Reference
Drug group A vasodilator and antihypertensive drug
Overdose danger rating Medium
Dependence rating Low
Prescription needed Yes
Available as generic No
Information for Users
Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.
How taken
Tablets.
Frequency and timing of doses
Once daily.
Adult dosage range
Hypertension 1mg (starting dose), increased gradually as necessary up to 20mg. Enlarged prostate 1mg (starting dose), increased gradually at 1-2-week intervals up to 8mg.
Onset of effect
Within 2 hours.
Duration of action
24 hours.
Diet advice
None.
Storage
Keep in a closed container in a cool, dry place out of the reach of children.
Missed dose
Take as soon as you remember. If your next dose is due within 6 hours, take a single dose now and skip the next.
Stopping the drug
Do not stop taking the drug without consulting your doctor; stopping the drug may lead to a rise in blood pressure.
Exceeding the dose
An occasional unintentional extra dose is unlikely to be a cause for concern. Larger overdoses may cause dizziness or fainting. Notify your doctor.
POSSIBLE ADVERSE EFFECTS
Nausea, headache, and weakness are common with doxazosin, but the main
problem is that it may cause dizziness or fainting when you stand up.
INTERACTIONS
None.
Special Precautions
Be sure to tell your doctor if:
You have long-term liver problems.
You are taking other medications.
Pregnancy
Safety in pregnancy not established. Discuss with your doctor.
Breast-feeding
The drug passes into the breast milk. Discuss with your doctor.
Infants and children
Not recommended.
Over 60
Reduced dose may be necessary. Take extra care when standing up until you have learned how the drug affects you.
Driving and hazardous work
Avoid such activities until you have learned how doxazosin affects you because the drug can cause drowsiness, dizziness, and fainting.
Alcohol
Avoid excessive amounts. Alcohol may increase some of the adverse effects of this drug, such as dizziness, drowsiness, and faintness.
Prolonged Use
No known problems.
