Cardura 1mg Tablets
It is used to treat the signs of an enlarged prostate.It is used to treat high blood pressure.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antihypertensive; Agent for Benign Prostatic Hyperplasia
Pharmacologic Class
Alpha-1 Adrenergic Blocker
Pregnancy Category
Category C
FDA Approved
Dec 1990
DEA Schedule
Not Controlled
Overview
What is this medicine?
Doxazosin is a medication used to treat high blood pressure (hypertension) and symptoms of an enlarged prostate (benign prostatic hyperplasia or BPH). It works by relaxing blood vessels, which lowers blood pressure, and by relaxing muscles in the prostate and bladder, which helps urine flow more easily.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, take it exactly as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely. Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a safe place, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless specifically instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to inquire about drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses. If you miss taking your medication for several days in a row, contact your doctor before restarting your medication regimen.
To get the most benefit from your medication, take it exactly as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely. Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a safe place, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless specifically instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to inquire about drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses. If you miss taking your medication for several days in a row, contact your doctor before restarting your medication regimen.
Lifestyle & Tips
- Take the first dose at bedtime to minimize the 'first-dose phenomenon' (sudden drop in blood pressure).
- Avoid sudden changes in position (e.g., standing up quickly from a sitting or lying position) to prevent dizziness or fainting.
- Avoid activities requiring mental alertness for the first few hours after the initial dose or dose increases.
- Limit alcohol intake, as it can increase the risk of dizziness and low blood pressure.
- Maintain adequate hydration to help prevent orthostatic hypotension.
- For BPH, continue regular follow-up with your doctor to monitor symptoms.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
Hypertension: 1 mg once daily; Benign Prostatic Hyperplasia (BPH): 1 mg once daily
Dose Range:
1 - 16 mg
Condition-Specific Dosing:
hypertension:
Initial 1 mg once daily, may be increased to 2 mg, 4 mg, 8 mg, and 16 mg once daily at 1- to 2-week intervals to achieve desired blood pressure reduction.
benignProstaticHyperplasia:
Initial 1 mg once daily, may be increased to 2 mg, 4 mg, and 8 mg once daily at 1- to 2-week intervals to achieve desired symptom improvement. Maximum recommended dose is 8 mg daily.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No dosage adjustment typically required.
Moderate:
No dosage adjustment typically required.
Severe:
No dosage adjustment typically required.
Dialysis:
Doxazosin is highly protein bound and not dialyzable. No specific adjustment for dialysis patients, but monitor for response.
Hepatic Impairment:
Mild:
Use with caution.
Moderate:
Use with caution; consider lower initial dose and slower titration. Monitor closely for adverse effects.
Severe:
Use with caution; consider lower initial dose and slower titration. Data are limited. Monitor closely for adverse effects.
Pharmacology
Mechanism of Action
Doxazosin is a selective alpha-1 adrenergic receptor antagonist. It competitively blocks postsynaptic alpha-1 adrenergic receptors, leading to vasodilation and a reduction in peripheral vascular resistance, thereby lowering blood pressure. In benign prostatic hyperplasia (BPH), it blocks alpha-1 receptors in the stromal smooth muscle of the prostate and bladder neck, leading to relaxation of smooth muscle and improved urine flow.
Pharmacokinetics
Absorption:
Bioavailability:
62-69%
Tmax:
2-3 hours
FoodEffect:
Minimal effect on absorption.
Distribution:
Vd:
1.6 L/kg
ProteinBinding:
>98%
CnssPenetration:
Limited
Elimination:
HalfLife:
22 hours
Clearance:
Not readily available (hepatic clearance)
ExcretionRoute:
Primarily fecal (63%), renal (9%)
Unchanged:
<5%
Pharmacodynamics
OnsetOfAction:
1-2 hours (for blood pressure lowering)
PeakEffect:
2-6 hours
DurationOfAction:
24 hours
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
New or worsening chest pain
Shortness of breath
Swelling in the arms or legs
A painful erection (priapism) or an erection that lasts longer than 4 hours, which can occur even when not having sex. If left untreated, this may lead to lasting sexual problems and impotence.
Other Possible Side Effects
Like all medications, this drug can cause side effects, although many people may not experience any or may only have mild symptoms. If you are bothered by any of the following side effects or if they persist, contact your doctor or seek medical help:
Dizziness
Drowsiness
Fatigue
Weakness
* Headache
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
New or worsening chest pain
Shortness of breath
Swelling in the arms or legs
A painful erection (priapism) or an erection that lasts longer than 4 hours, which can occur even when not having sex. If left untreated, this may lead to lasting sexual problems and impotence.
Other Possible Side Effects
Like all medications, this drug can cause side effects, although many people may not experience any or may only have mild symptoms. If you are bothered by any of the following side effects or if they persist, contact your doctor or seek medical help:
Dizziness
Drowsiness
Fatigue
Weakness
* Headache
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or lightheadedness, especially when standing up
- Fainting spells (syncope)
- Chest pain or palpitations
- Swelling in ankles or feet
- Persistent or painful erection (priapism)
- Signs of liver problems (e.g., yellowing of skin/eyes, dark urine, persistent nausea/vomiting)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have liver disease, as this may affect how your body processes the medication.
* Potential interactions with other medications or health conditions. To ensure safe use, disclose all of your:
+ Prescription medications
+ Over-the-counter (OTC) medications
+ Natural products
+ Vitamins
+ Health problems
Your doctor and pharmacist will help determine whether it is safe to take this medication with your other medications and health conditions. Do not start, stop, or change the dose of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have liver disease, as this may affect how your body processes the medication.
* Potential interactions with other medications or health conditions. To ensure safe use, disclose all of your:
+ Prescription medications
+ Over-the-counter (OTC) medications
+ Natural products
+ Vitamins
+ Health problems
Your doctor and pharmacist will help determine whether it is safe to take this medication with your other medications and health conditions. Do not start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
Important Warnings and Precautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Caution with Daily Activities
Do not operate a vehicle or engage in activities that require alertness for 24 hours after taking your first dose, after any dose increase, or if you restart the medication after stopping it. Ensure you understand how this medication affects you before driving or performing other tasks that require attention.
Preventing Dizziness and Falls
To minimize the risk of dizziness or fainting, stand up slowly when getting up from a sitting or lying down position. Be cautious when climbing stairs.
Monitoring Your Condition
Check your blood pressure as directed by your healthcare provider.
Special Considerations
If you are scheduled to undergo cataract surgery or any other eye procedure, consult with your doctor. If you are taking this medication for an enlarged prostate, follow your doctor's instructions for regular rectal exams (to check the prostate gland) and blood tests (PSA test).
Interactions with Other Medications
If you have high blood pressure and are taking this medication, consult with your doctor before using over-the-counter (OTC) products that may increase blood pressure, such as:
- Cough or cold medications
- Diet pills
- Stimulants
- Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen
- Certain natural products or aids
Age-Related Precautions
If you are 70 years or older, use this medication with caution, as you may be more susceptible to side effects.
Pregnancy and Breastfeeding
Inform your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. You and your doctor will need to discuss the potential benefits and risks of this medication to you and your baby.
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Caution with Daily Activities
Do not operate a vehicle or engage in activities that require alertness for 24 hours after taking your first dose, after any dose increase, or if you restart the medication after stopping it. Ensure you understand how this medication affects you before driving or performing other tasks that require attention.
Preventing Dizziness and Falls
To minimize the risk of dizziness or fainting, stand up slowly when getting up from a sitting or lying down position. Be cautious when climbing stairs.
Monitoring Your Condition
Check your blood pressure as directed by your healthcare provider.
Special Considerations
If you are scheduled to undergo cataract surgery or any other eye procedure, consult with your doctor. If you are taking this medication for an enlarged prostate, follow your doctor's instructions for regular rectal exams (to check the prostate gland) and blood tests (PSA test).
Interactions with Other Medications
If you have high blood pressure and are taking this medication, consult with your doctor before using over-the-counter (OTC) products that may increase blood pressure, such as:
- Cough or cold medications
- Diet pills
- Stimulants
- Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen
- Certain natural products or aids
Age-Related Precautions
If you are 70 years or older, use this medication with caution, as you may be more susceptible to side effects.
Pregnancy and Breastfeeding
Inform your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. You and your doctor will need to discuss the potential benefits and risks of this medication to you and your baby.
Overdose Information
Overdose Symptoms:
- Profound hypotension (extremely low blood pressure)
- Dizziness
- Fainting
- Tachycardia (rapid heart rate)
What to Do:
Call 1-800-222-1222 (Poison Control). Support cardiovascular system. Place patient in supine position with legs elevated. If severe, administer vasopressors and volume expanders as needed. Doxazosin is highly protein bound and not dialyzable.
Drug Interactions
Major Interactions
- PDE5 inhibitors (e.g., sildenafil, tadalafil, vardenafil, avanafil): Concomitant use can lead to symptomatic hypotension, especially in BPH patients. If co-administration is necessary, patients should be stable on alpha-blocker therapy before initiating a PDE5 inhibitor at the lowest dose.
- Other alpha-blockers (e.g., prazosin, terazosin, tamsulosin): Increased risk of hypotension.
Moderate Interactions
- Antihypertensive agents (e.g., beta-blockers, diuretics, ACE inhibitors, ARBs, calcium channel blockers): Additive hypotensive effects.
- CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, ritonavir): May increase doxazosin plasma concentrations, potentially increasing hypotensive effects. Monitor for increased adverse effects.
- Ergot alkaloids (e.g., ergotamine): Theoretical risk of increased peripheral vasoconstriction.
Minor Interactions
- NSAIDs (e.g., ibuprofen, naproxen): May reduce the antihypertensive effect of doxazosin.
Monitoring
Baseline Monitoring
Blood Pressure (sitting and standing)
Rationale: To establish baseline and assess for orthostatic hypotension, especially before first dose and dose titrations.
Timing: Prior to initiation of therapy and before each dose increase.
Liver Function Tests (LFTs)
Rationale: Doxazosin is extensively metabolized by the liver; baseline assessment is prudent, especially in patients with suspected hepatic impairment.
Timing: Prior to initiation in patients with pre-existing liver disease or risk factors.
Routine Monitoring
Blood Pressure (sitting and standing)
Frequency: Regularly, especially during dose titration and periodically thereafter.
Target: Individualized based on treatment goals (e.g., <130/80 mmHg for hypertension).
Action Threshold: Significant orthostatic drop (>20 mmHg systolic or >10 mmHg diastolic) or symptomatic hypotension warrants dose adjustment or discontinuation.
Benign Prostatic Hyperplasia (BPH) symptoms (e.g., AUA symptom score)
Frequency: Periodically, to assess treatment efficacy.
Target: Improvement in symptom score.
Action Threshold: Lack of symptom improvement or worsening symptoms may indicate need for dose adjustment or alternative therapy.
Symptom Monitoring
- Dizziness
- Lightheadedness
- Syncope (fainting)
- Palpitations
- Fatigue
- Headache
- Nasal congestion
- Priapism (prolonged erection, rare but serious)
Special Patient Groups
Pregnancy
Category C. Animal studies have shown adverse effects on the fetus, but there are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Potential for developmental abnormalities based on animal data; human data lacking.
Second Trimester:
Potential for developmental abnormalities based on animal data; human data lacking.
Third Trimester:
Potential for developmental abnormalities based on animal data; human data lacking. Risk of neonatal hypotension if used close to delivery.
Lactation
No human data are available on the presence of doxazosin in human milk, the effects on the breastfed infant, or the effects on milk production. Doxazosin is highly protein bound, suggesting low excretion into breast milk. Use with caution; monitor infant for drowsiness and lethargy.
Infant Risk:
Risk cannot be ruled out; monitor for adverse effects.
Pediatric Use
Safety and effectiveness have not been established in pediatric patients.
Geriatric Use
Increased risk of orthostatic hypotension and associated adverse events (e.g., falls) due to age-related changes in blood pressure regulation. Initiate therapy with the lowest dose (1 mg) and titrate slowly. Monitor blood pressure closely, especially standing blood pressure.
Clinical Information
Clinical Pearls
- Doxazosin is effective for both hypertension and BPH, making it a good choice for patients with both conditions.
- The 'first-dose phenomenon' (marked orthostatic hypotension) is a known risk, especially with the initial dose or dose increases. Advise patients to take the first dose at bedtime.
- Extended-release (XL) formulation (Cardura XL) is available, which may reduce the risk of orthostatic hypotension and allows for once-daily dosing without the need for bedtime administration.
- Patients undergoing cataract surgery should inform their ophthalmologist about doxazosin use due to the risk of Intraoperative Floppy Iris Syndrome (IFIS).
Alternative Therapies
- For Hypertension: ACE inhibitors (e.g., lisinopril), Angiotensin Receptor Blockers (ARBs) (e.g., losartan), Calcium Channel Blockers (e.g., amlodipine), Thiazide Diuretics (e.g., hydrochlorothiazide), Beta-blockers (e.g., metoprolol).
- For Benign Prostatic Hyperplasia (BPH): Other alpha-1 blockers (e.g., tamsulosin, alfuzosin, silodosin), 5-alpha reductase inhibitors (e.g., finasteride, dutasteride), PDE5 inhibitors (e.g., tadalafil), surgical options.
Cost & Coverage
Average Cost:
$10 - $50 per 30 tablets (generic 1mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (generic)
General Drug Facts
If your symptoms or health condition do not improve or worsen over time, it is essential to contact your doctor for further evaluation and guidance.
To ensure safe and effective treatment, never share your medication with others or take medication prescribed to someone else.
Some medications may come with an additional patient information leaflet, so it is a good idea to check with your pharmacist for more information.
If you have any questions or concerns about your medication, do not hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider for guidance and support.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide detailed information about the overdose, including the name of the medication taken, the amount, and the time it occurred.
To ensure safe and effective treatment, never share your medication with others or take medication prescribed to someone else.
Some medications may come with an additional patient information leaflet, so it is a good idea to check with your pharmacist for more information.
If you have any questions or concerns about your medication, do not hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider for guidance and support.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide detailed information about the overdose, including the name of the medication taken, the amount, and the time it occurred.