Cardura 8mg 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 (BPH)
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) in men. 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, it's essential to use it 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're feeling well.
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 the bathroom. 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 instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to explore local drug take-back programs for safe and responsible disposal.
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. Avoid taking two doses at the same time or taking extra doses. If you've missed 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, it's essential to use it 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're feeling well.
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 the bathroom. 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 instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to explore local drug take-back programs for safe and responsible disposal.
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. Avoid taking two doses at the same time or taking extra doses. If you've missed taking your medication for several days in a row, contact your doctor before restarting your medication regimen.
Lifestyle & Tips
- Take the first dose and any new increased doses at bedtime to minimize the risk of dizziness or fainting.
- Avoid sudden changes in position (e.g., standing up quickly from a sitting or lying position) to prevent dizziness or lightheadedness.
- Avoid activities requiring mental alertness, such as driving or operating machinery, for at least 12 hours after the first dose or any dose increase.
- Limit alcohol intake, as it can increase the risk of dizziness and low blood pressure.
- Maintain adequate hydration, especially during hot weather or exercise.
- For BPH, regular exercise and a healthy diet can complement treatment.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
For Hypertension: Initial 1 mg once daily; maintenance 1-16 mg once daily. For BPH: Initial 1 mg once daily; maintenance 1-8 mg once daily.
Dose Range:
1 - 16 mg
Condition-Specific Dosing:
Hypertension:
Initial 1 mg once daily, titrate up to 16 mg once daily based on response and tolerability.
Benign Prostatic Hyperplasia (BPH):
Initial 1 mg once daily, titrate up to 8 mg once daily based on response and tolerability. Doses above 4 mg generally do not provide additional benefit for BPH.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
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 for dialysis patients, but monitor for exaggerated hypotensive response.
Hepatic Impairment:
Mild:
Use with caution; no specific adjustment recommended.
Moderate:
Use with caution; consider lower initial doses and slower titration. Monitor for adverse effects.
Severe:
Use with caution; consider lower initial doses and slower titration. Monitor for adverse effects. Doxazosin is extensively metabolized by the liver.
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:
62-69%
Tmax:
2-3 hours
FoodEffect:
Food does not significantly affect the absorption of doxazosin.
Distribution:
Vd:
1.6 L/kg
ProteinBinding:
>98%
CnssPenetration:
Limited
Elimination:
HalfLife:
22 hours
Clearance:
Not available (systemic clearance approx. 2 L/min)
ExcretionRoute:
Primarily fecal (63%), minor renal (9%)
Unchanged:
<5%
Pharmacodynamics
OnsetOfAction:
1-2 hours (for blood pressure lowering)
PeakEffect:
2-6 hours (for blood pressure lowering)
DurationOfAction:
24 hours
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while 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. While many people may not experience any side effects or only minor ones, it's 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 persist, contact your doctor:
Dizziness
Drowsiness
Fatigue
Weakness
* Headache
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, 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. Your doctor can provide medical advice on managing side effects.
Although rare, some people may experience severe and potentially life-threatening side effects while 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. While many people may not experience any side effects or only minor ones, it's 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 persist, contact your doctor:
Dizziness
Drowsiness
Fatigue
Weakness
* Headache
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, 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. Your doctor can provide medical advice on managing side effects.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or lightheadedness, especially when standing up (orthostatic hypotension)
- Fainting (syncope)
- Persistent headache
- Unusual fatigue or weakness
- Swelling in the ankles or feet
- Chest pain or palpitations
- Priapism (prolonged, painful erection lasting more 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 allergic reaction you experienced, including any symptoms that occurred.
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 medications
+ Over-the-counter (OTC) medications
+ Natural products
+ Vitamins
Any existing health problems, as these may impact the safety and effectiveness of this medication.
Remember to consult with your doctor before making any changes to your medication regimen, including starting, stopping, or adjusting the dose of any medication. Your doctor and pharmacist will help determine if it is safe to take this medication with your other medications and health conditions.
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 the use of this 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
Any existing health problems, as these may impact the safety and effectiveness of this medication.
Remember to consult with your doctor before making any changes to your medication regimen, including starting, stopping, or adjusting the dose of any medication. Your doctor and pharmacist will help determine if it is safe to take this medication with your other medications and health conditions.
Precautions & Cautions
Important Warnings and Cautions
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
For 24 hours after your first dose, and also after any increase in dose or when restarting the medication after stopping it, avoid driving or engaging in activities that require alertness. Before resuming these activities, make sure you understand how this medication affects you.
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, 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
For 24 hours after your first dose, and also after any increase in dose or when restarting the medication after stopping it, avoid driving or engaging in activities that require alertness. Before resuming these activities, make sure you understand how this medication affects you.
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, 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:
In case of overdose, immediately contact a poison control center or emergency medical services. Call 1-800-222-1222 for the Poison Control Center. Management typically involves placing the patient in a supine position with legs elevated to restore blood pressure. If this is insufficient, vasopressors may be administered. Volume expanders may also be used. Dialysis is not effective due to high protein binding.
Drug Interactions
Major Interactions
- PDE5 inhibitors (e.g., sildenafil, tadalafil, vardenafil, avanafil): Concomitant use can lead to symptomatic hypotension (e.g., dizziness, lightheadedness, syncope). Patients should be stable on alpha-blocker therapy before initiating a PDE5 inhibitor, and PDE5 inhibitors should be started at the lowest dose.
Moderate Interactions
- Other antihypertensive agents: Additive hypotensive effects.
- Beta-blockers: Increased risk of first-dose phenomenon and orthostatic hypotension.
- CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, ritonavir): May increase doxazosin exposure, though CYP3A4 is a minor metabolic pathway for doxazosin. Monitor for increased hypotensive effects.
Minor Interactions
- NSAIDs: May reduce the antihypertensive effect of doxazosin.
- Estrogens: May cause fluid retention, potentially counteracting antihypertensive effects.
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: Before initiation and before each dose titration.
Benign Prostatic Hyperplasia (BPH) symptom score (e.g., AUA Symptom Index)
Rationale: To establish baseline symptom severity and monitor treatment efficacy for BPH.
Timing: Before initiation.
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.
Benign Prostatic Hyperplasia (BPH) symptom score
Frequency: Periodically (e.g., every 3-6 months) after stable dosing.
Target: Reduction in AUA score.
Action Threshold: Lack of symptom improvement or worsening symptoms.
Liver Function Tests (LFTs)
Frequency: Periodically, especially in patients with pre-existing hepatic impairment or if symptoms of liver dysfunction develop.
Target: Within normal limits.
Action Threshold: Significant elevation of liver enzymes.
Symptom Monitoring
- Dizziness
- Lightheadedness
- Fainting (syncope)
- Palpitations
- Fatigue
- Headache
- Nasal congestion
- Peripheral edema
- Urinary symptoms (for BPH: frequency, urgency, nocturia, weak stream)
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:
Limited human data; animal studies show some fetal effects at high doses.
Second Trimester:
Limited human data; animal studies show some fetal effects at high doses.
Third Trimester:
Limited human data; animal studies show some fetal effects at high doses. Potential for neonatal hypotension if used close to delivery.
Lactation
Doxazosin is excreted in human milk. Caution should be exercised when doxazosin is administered to a nursing mother. The decision to discontinue nursing or discontinue the drug should take into account the importance of the drug to the mother.
Infant Risk:
L3 (Moderately safe). Potential for infant hypotension, lethargy, or other alpha-blocker effects. Monitor breastfed infant for adverse effects.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Doxazosin is not recommended for use in children.
Geriatric Use
Elderly patients may be more sensitive to the hypotensive effects of doxazosin, particularly orthostatic hypotension. Initiate therapy with the lowest dose (1 mg) and titrate slowly, monitoring blood pressure carefully. No overall differences in efficacy or safety were observed between older and younger patients in clinical trials, but greater sensitivity of some older individuals cannot be ruled out.
Clinical Information
Clinical Pearls
- The 'first-dose phenomenon' (marked postural hypotension, rarely syncope) can occur, especially with the initial dose or with dose increases. To minimize this, administer the first dose and any subsequent dose increases at bedtime.
- Advise patients to avoid situations where injury could result if syncope occurs (e.g., driving, operating machinery) for 12-24 hours after the initial dose or dose increase.
- Doxazosin is effective for both hypertension and BPH, offering a dual benefit for male patients with both conditions.
- For BPH, symptom improvement may take several weeks of consistent use.
- Patients should be advised to report any prolonged, painful erection (priapism) immediately, as it is a rare but serious side effect requiring urgent medical attention.
Alternative Therapies
- Other Alpha-1 Adrenergic Blockers (for BPH and/or Hypertension): Terazosin, Prazosin, Tamsulosin, Alfuzosin, Silodosin.
- For Hypertension: Thiazide diuretics, ACE inhibitors, ARBs, Calcium Channel Blockers, Beta-blockers.
- For BPH: 5-alpha reductase inhibitors (e.g., finasteride, dutasteride), PDE5 inhibitors (e.g., tadalafil), Anticholinergics (for overactive bladder symptoms), Surgical options.
Cost & Coverage
Average Cost:
Varies widely, typically $10-$50 per 30 tablets (generic 8mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (for generic)
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 medication, including the amount taken and the time it happened, to facilitate prompt and effective treatment.