Cardura 2mg 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, Benign Prostatic Hyperplasia (BPH) agent
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 improve urine flow.
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
To maintain the quality and safety of your medication, store it at room temperature in a dry location, avoiding bathrooms. Keep all medications in a secure place, out of the reach of children and pets. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless specifically instructed to do so. Instead, consult with your pharmacist for guidance on the proper disposal method. You may also want to inquire about drug take-back programs available 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 is 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
To maintain the quality and safety of your medication, store it at room temperature in a dry location, avoiding bathrooms. Keep all medications in a secure place, out of the reach of children and pets. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless specifically instructed to do so. Instead, consult with your pharmacist for guidance on the proper disposal method. You may also want to inquire about drug take-back programs available 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 is 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 increase.
- Limit alcohol intake, as it can increase the risk of dizziness and low blood pressure.
- Maintain adequate hydration.
- For BPH, continue regular prostate check-ups as advised by your doctor.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
Hypertension: Initially 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. Benign Prostatic Hyperplasia (BPH): Initially 1 mg once daily. May be increased to 2 mg, 4 mg, and 8 mg once daily at 1- to 2-week intervals.
Dose Range:
1 - 16 mg
Condition-Specific Dosing:
hypertension:
Max 16 mg/day
bph:
Max 8 mg/day
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established (Safety and efficacy not established for hypertension or BPH in pediatric patients.)
Dose Adjustments
Renal Impairment:
Mild:
No dosage adjustment necessary
Moderate:
No dosage adjustment necessary
Severe:
No dosage adjustment necessary
Dialysis:
Doxazosin is highly protein bound and not dialyzable. No specific adjustment recommended, but monitor patient response.
Hepatic Impairment:
Mild:
Use with caution; monitor blood pressure closely.
Moderate:
Use with caution; consider lower initial dose and slower titration. Monitor blood pressure closely.
Severe:
Use with caution; not studied in severe hepatic impairment. Avoid if possible or use with extreme caution and close monitoring.
Pharmacology
Mechanism of Action
Doxazosin is a selective alpha-1 adrenergic receptor antagonist. It blocks alpha-1 receptors in vascular smooth muscle, leading to vasodilation and a reduction in peripheral vascular resistance, thus lowering blood pressure. In BPH, it blocks alpha-1 receptors in the stromal and capsular tissues of the prostate and in the bladder neck, leading to relaxation of smooth muscle and improved urine flow.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 62-69%
Tmax:
2-3 hours
FoodEffect:
Food does not significantly affect the extent of absorption.
Distribution:
Vd:
Approximately 1.6 L/kg
ProteinBinding:
Approximately 98%
CnssPenetration:
Limited
Elimination:
HalfLife:
Approximately 22 hours
Clearance:
Approximately 81 mL/min
ExcretionRoute:
Primarily fecal (63%), with a small amount excreted in urine (9%)
Unchanged:
Less than 5% (urine)
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 experience any of the following symptoms, contact your doctor or seek medical attention immediately:
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 do not experience any side effects or only have mild ones, it is essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
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 experience any of the following symptoms, contact your doctor or seek medical attention immediately:
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 do not experience any side effects or only have mild ones, it is essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
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 (syncope)
- Persistent headache
- Unusual fatigue or weakness
- Swelling in ankles or feet
- Chest pain or palpitations
- Priapism (erection lasting longer than 4 hours) - seek immediate medical attention.
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 symptoms you experienced.
If you have liver disease, as this may affect the use of this medication.
* Potential interactions with other medications or health conditions. To ensure safe use, disclose all of your:
+ Prescription and over-the-counter (OTC) medications
+ Natural products
+ Vitamins
+ Health problems
Your doctor and pharmacist need this information to assess the safety of taking this medication with your other medications and health conditions. Never 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 symptoms you experienced.
If you have liver disease, as this may affect the use of this medication.
* Potential interactions with other medications or health conditions. To ensure safe use, disclose all of your:
+ Prescription and over-the-counter (OTC) medications
+ Natural products
+ Vitamins
+ Health problems
Your doctor and pharmacist need this information to assess the safety of taking this medication with your other medications and health conditions. Never 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 rising from a seated or lying position. Exercise caution 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 another eye procedure, consult with your doctor. For individuals taking this medication for an enlarged prostate, follow your doctor's instructions for regular rectal exams (to assess the prostate gland) and blood tests (PSA tests).
Interactions with Other Medications
If you have high blood pressure and are taking this medication, discuss 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 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 rising from a seated or lying position. Exercise caution 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 another eye procedure, consult with your doctor. For individuals taking this medication for an enlarged prostate, follow your doctor's instructions for regular rectal exams (to assess the prostate gland) and blood tests (PSA tests).
Interactions with Other Medications
If you have high blood pressure and are taking this medication, discuss 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 to you and your baby.
Overdose Information
Overdose Symptoms:
- Profound hypotension (extremely low blood pressure)
- Dizziness
- Fainting
- Tachycardia (rapid heart rate)
What to Do:
Supportive care. 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. Call 911 or Poison Control at 1-800-222-1222 immediately.
Drug Interactions
Major Interactions
- PDE5 inhibitors (e.g., sildenafil, tadalafil, vardenafil): Concomitant use can lead to symptomatic hypotension. Initiate PDE5 inhibitors at the lowest dose and only after the patient is stable on doxazosin. Separate dosing by at least 6 hours if possible.
- Other alpha-1 blockers (e.g., prazosin, terazosin): Increased risk of hypotension.
Moderate Interactions
- Antihypertensive agents (e.g., beta-blockers, diuretics, ACE inhibitors): Additive hypotensive effects.
- CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, ritonavir): May increase doxazosin plasma concentrations, potentially increasing hypotensive effects. Monitor for increased adverse effects.
- CYP2D6 inhibitors (e.g., quinidine, fluoxetine): May increase doxazosin plasma concentrations.
- NSAIDs (e.g., ibuprofen, naproxen): May reduce the antihypertensive effect of doxazosin.
- Epinephrine: May reverse the pressor effect of epinephrine, leading to increased hypotension and tachycardia.
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Blood Pressure (BP)
Rationale: To establish baseline and assess the need for treatment.
Timing: Prior to initiation of therapy.
Orthostatic BP (standing and sitting/supine)
Rationale: To assess risk of first-dose phenomenon and orthostatic hypotension.
Timing: Prior to initiation and with dose titrations.
International Prostate Symptom Score (IPSS) or AUA Symptom Score
Rationale: To quantify baseline BPH symptoms and track improvement.
Timing: Prior to initiation for BPH.
Routine Monitoring
Blood Pressure (BP)
Frequency: Regularly, especially during dose titration and periodically thereafter.
Target: Individualized, typically <130/80 mmHg for hypertension.
Action Threshold: Persistent hypotension, or inadequate BP control requiring dose adjustment.
Orthostatic BP (standing and sitting/supine)
Frequency: With each dose titration and if symptoms of dizziness or lightheadedness occur.
Target: No significant orthostatic drop (e.g., <20 mmHg systolic, <10 mmHg diastolic).
Action Threshold: Symptomatic orthostasis or significant asymptomatic drop (e.g., >20/10 mmHg).
BPH Symptom Score (IPSS/AUA)
Frequency: Periodically (e.g., every 3-6 months) for BPH.
Target: Improvement in symptom score.
Action Threshold: Lack of improvement or worsening symptoms.
Symptom Monitoring
- Dizziness
- Lightheadedness
- Fainting (syncope)
- Palpitations
- Headache
- Fatigue
- Nasal congestion
- Peripheral edema
- Priapism (prolonged erection)
Special Patient Groups
Pregnancy
Category C. Doxazosin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Animal studies have shown adverse effects at high doses.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm based on animal data, but human data are limited.
Second Trimester:
Potential for fetal harm based on animal data, but human data are limited.
Third Trimester:
Potential for fetal harm based on animal data, but human data are limited. Risk of neonatal hypotension if used close to delivery.
Lactation
L3 (Moderately Safe). Doxazosin is excreted in human milk in small amounts. The clinical significance of this is unknown. Use with caution; monitor breastfed infant for adverse effects (e.g., lethargy, poor feeding, hypotension).
Infant Risk:
Low to moderate risk of adverse effects in breastfed infants. Monitor for drowsiness, poor feeding, and hypotension.
Pediatric Use
Safety and effectiveness have not been established in pediatric patients for either hypertension or BPH. Not recommended for use in this population.
Geriatric Use
Elderly patients may be more sensitive to the hypotensive effects of doxazosin, particularly orthostatic hypotension. Initiate therapy at the lowest dose (1 mg) and titrate slowly. Monitor blood pressure closely.
Clinical Information
Clinical Pearls
- The 'first-dose phenomenon' (marked postural hypotension) can occur within 2-6 hours of the initial dose or a dose increase. To minimize this, administer the first dose and any subsequent dose increases at bedtime.
- Advise patients to avoid situations where injury could result from syncope (e.g., driving, operating machinery) for 12-24 hours after the initial dose or dose increase.
- Doxazosin is effective for both hypertension and BPH, making it a good choice for patients with both conditions.
- For BPH, symptomatic improvement may take several weeks.
- 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: Other alpha-1 blockers (e.g., prazosin, terazosin), ACE inhibitors, ARBs, beta-blockers, calcium channel blockers, diuretics.
- For 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:
Varies, typically $10-$50 per 30 tablets (generic 2mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (generic), Tier 3 or higher (brand)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the overdose, including the medication taken, the amount, and the time it occurred.