Terazosin 5mg Capsules
It is used to treat high blood pressure.It is used to treat the signs of an enlarged prostate.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
Aug 1987
DEA Schedule
Not Controlled
Overview
What is this medicine?
Terazosin is a medication that helps relax blood vessels, which lowers blood pressure. It also relaxes muscles in the prostate and bladder, making it easier to urinate for men with an enlarged prostate. It's often taken at bedtime to help reduce dizziness.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take this medication at bedtime as directed. Continue taking the medication as prescribed by your doctor or healthcare provider, even if you start feeling well.
Storing and Disposing of Your Medication
Store the medication at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of medications, consult your pharmacist. You may also want to check if there are 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 dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses. If you miss two or more days of this medication, contact your doctor for guidance on how to restart your treatment.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take this medication at bedtime as directed. Continue taking the medication as prescribed by your doctor or healthcare provider, even if you start feeling well.
Storing and Disposing of Your Medication
Store the medication at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of medications, consult your pharmacist. You may also want to check if there are 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 dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses. If you miss two or more days of this medication, contact your doctor for guidance on how to restart your treatment.
Lifestyle & Tips
- Take the first dose and any dose increases 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 12 hours after the first dose or any dose increase.
- Limit alcohol consumption, as it can increase the risk of dizziness and low blood pressure.
- Stay hydrated, especially in hot weather or during exercise, to prevent dehydration and low blood pressure.
- Inform your doctor or eye surgeon if you are taking terazosin before cataract surgery, as it can cause a condition called Intraoperative Floppy Iris Syndrome (IFIS).
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial 1 mg orally once daily at bedtime; titrate slowly based on response and tolerability. Usual maintenance dose for hypertension is 1-5 mg daily; for BPH, 5-10 mg daily.
Dose Range:
1 - 20 mg
Condition-Specific Dosing:
hypertension:
Initial 1 mg orally once daily at bedtime; may be slowly increased to 1 mg, 2 mg, 5 mg, and 10 mg at weekly intervals to achieve desired blood pressure reduction. Max 20 mg/day.
benignProstaticHyperplasia:
Initial 1 mg orally once daily at bedtime; may be slowly increased to 2 mg, 5 mg, and 10 mg at weekly or biweekly intervals to achieve desired symptom improvement. Max 20 mg/day.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment required.
Moderate:
No specific dose adjustment required.
Severe:
No specific dose adjustment required, but use with caution due to potential for increased sensitivity to hypotensive effects.
Dialysis:
Not significantly removed by dialysis; no specific adjustment needed, but monitor response.
Hepatic Impairment:
Mild:
Use with caution; consider lower initial doses and slower titration.
Moderate:
Use with caution; consider lower initial doses and slower titration.
Severe:
Use with caution; consider lower initial doses and slower titration. Limited data available.
Pharmacology
Mechanism of Action
Terazosin 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 smooth muscle of the prostate and bladder neck, leading to relaxation and improved urine flow.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 90%
Tmax:
1-2 hours
FoodEffect:
Food may delay the rate of absorption but does not significantly affect the extent of absorption (AUC).
Distribution:
Vd:
Approximately 25 L
ProteinBinding:
90-94%
CnssPenetration:
Limited
Elimination:
HalfLife:
9-12 hours
Clearance:
Approximately 80 mL/min
ExcretionRoute:
Biliary/fecal (approximately 60%) and renal/urinary (approximately 40%)
Unchanged:
Approximately 10% (urine), 20% (feces)
Pharmacodynamics
OnsetOfAction:
Within 1 hour
PeakEffect:
2-3 hours
DurationOfAction:
Up to 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
Changes in vision
Abnormal or rapid heartbeat
Swelling in the arms or legs
A painful erection (hard penis) or an erection that lasts longer than 4 hours, which may occur even when not having sex. If left untreated, this can lead to long-term sexual problems and impotence.
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although 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 or seek medical help:
Feeling dizzy, sleepy, tired, or weak
Stuffy nose
* Headache
Reporting Side Effects
This list is not exhaustive, and you may experience other 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
Changes in vision
Abnormal or rapid heartbeat
Swelling in the arms or legs
A painful erection (hard penis) or an erection that lasts longer than 4 hours, which may occur even when not having sex. If left untreated, this can lead to long-term sexual problems and impotence.
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although 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 or seek medical help:
Feeling dizzy, sleepy, tired, or weak
Stuffy nose
* Headache
Reporting Side Effects
This list is not exhaustive, and you may experience other 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 fainting (syncope)
- Persistent lightheadedness
- Rapid or irregular heartbeat
- Chest pain
- Swelling of ankles or feet
- Difficulty breathing
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, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
Potential interactions with other medications or health conditions. This medication may affect or be affected by other drugs or health problems, so it is crucial to disclose all relevant information.
To ensure safe treatment, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Natural products and vitamins you are using
* Any health problems you have
Carefully review your medications and health conditions with your doctor to confirm that it is safe to take this medication. Do not initiate, discontinue, or adjust the dosage 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, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
Potential interactions with other medications or health conditions. This medication may affect or be affected by other drugs or health problems, so it is crucial to disclose all relevant information.
To ensure safe treatment, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Natural products and vitamins you are using
* Any health problems you have
Carefully review your medications and health conditions with your doctor to confirm that it is safe to take this medication. Do not initiate, discontinue, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
To ensure your safety, avoid driving or engaging in activities that require alertness for 12 hours after taking the first dose, after any dose increase, and when restarting the medication after a period of stopping it. Before resuming these activities, make sure you understand how this medication affects you.
To minimize the risk of dizziness or fainting, get up slowly from a sitting or lying down position. Be cautious when climbing stairs.
If you are scheduled to undergo cataract surgery or any other eye procedure, consult with your doctor beforehand.
Monitor your blood pressure as directed by your healthcare provider.
For individuals taking this medication for an enlarged prostate, follow your doctor's recommendations for regular rectal exams to check the prostate gland and blood tests, including the Prostate-Specific Antigen (PSA) test.
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, and certain natural products or aids.
Consult with your doctor before consuming alcohol while taking this medication.
Be aware that this medication may interfere with certain laboratory tests. Inform all your healthcare providers and laboratory personnel that you are taking this medication.
If you are pregnant, plan to become pregnant, or are breastfeeding, discuss the benefits and risks of this medication with your doctor to make an informed decision about its use.
To ensure your safety, avoid driving or engaging in activities that require alertness for 12 hours after taking the first dose, after any dose increase, and when restarting the medication after a period of stopping it. Before resuming these activities, make sure you understand how this medication affects you.
To minimize the risk of dizziness or fainting, get up slowly from a sitting or lying down position. Be cautious when climbing stairs.
If you are scheduled to undergo cataract surgery or any other eye procedure, consult with your doctor beforehand.
Monitor your blood pressure as directed by your healthcare provider.
For individuals taking this medication for an enlarged prostate, follow your doctor's recommendations for regular rectal exams to check the prostate gland and blood tests, including the Prostate-Specific Antigen (PSA) test.
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, and certain natural products or aids.
Consult with your doctor before consuming alcohol while taking this medication.
Be aware that this medication may interfere with certain laboratory tests. Inform all your healthcare providers and laboratory personnel that you are taking this medication.
If you are pregnant, plan to become pregnant, or are breastfeeding, discuss the benefits and risks of this medication with your doctor to make an informed decision about its use.
Overdose Information
Overdose Symptoms:
- Profound hypotension (very low blood pressure)
- Dizziness
- Fainting
- Tachycardia (rapid heart rate)
What to Do:
Call 1-800-222-1222 (Poison Control). Management is primarily supportive, including placing the patient in a supine position with legs elevated, and if necessary, administering vasopressors and fluid expanders.
Drug Interactions
Major Interactions
- PDE5 inhibitors (e.g., sildenafil, tadalafil, vardenafil, avanafil): Concomitant use can lead to additive hypotensive effects and symptomatic hypotension. Should be used with caution, and patients should be stable on alpha-blocker therapy before initiating PDE5 inhibitors at the lowest dose.
Moderate Interactions
- Other antihypertensive agents (e.g., beta-blockers, calcium channel blockers, diuretics, ACE inhibitors): May cause additive hypotensive effects. Dose adjustment of either agent may be necessary.
- NSAIDs (Nonsteroidal Anti-inflammatory Drugs): May reduce the antihypertensive effect of terazosin.
- Alcohol: May enhance hypotensive effects.
Monitoring
Baseline Monitoring
Blood Pressure (sitting and standing)
Rationale: To establish baseline and assess for orthostatic hypotension, especially with the first dose.
Timing: Before initiation of therapy and before each dose increase.
BPH Symptom Score (e.g., AUA Symptom Score)
Rationale: To establish baseline severity of BPH symptoms and monitor treatment efficacy.
Timing: Before initiation of therapy.
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 requires dose adjustment or discontinuation.
BPH Symptom Score
Frequency: Periodically (e.g., every 3-6 months) to assess symptom improvement.
Target: Reduction in symptom score.
Action Threshold: Lack of improvement or worsening symptoms may indicate need for dose adjustment or alternative therapy.
Symptom Monitoring
- Dizziness
- Lightheadedness
- Syncope (fainting), especially with the first dose or dose increases
- Palpitations
- Headache
- Nasal congestion
- Fatigue
- Edema
Special Patient Groups
Pregnancy
Category C. Use only if the potential benefit justifies the potential risk to the fetus. Animal studies have shown adverse effects, but there are no adequate and well-controlled studies in pregnant women.
Trimester-Specific Risks:
First Trimester:
Potential risk based on animal data; human data lacking.
Second Trimester:
Potential risk based on animal data; human data lacking.
Third Trimester:
Potential risk based on animal data; human data lacking.
Lactation
It is not known whether terazosin is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when terazosin is administered to a nursing woman.
Infant Risk:
Risk unknown; potential for adverse effects on the infant.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Not recommended for use in children.
Geriatric Use
Geriatric patients may be more sensitive to the hypotensive effects of terazosin. Initiate therapy with the lowest dose (1 mg) and titrate slowly. Monitor blood pressure closely, especially for orthostatic changes.
Clinical Information
Clinical Pearls
- The 'first-dose phenomenon' (marked orthostatic hypotension, dizziness, syncope) is a significant concern, especially with the initial dose or dose increases. Advise patients to take the first dose at bedtime.
- Terazosin is effective for both hypertension and BPH, offering a dual benefit for men with both conditions.
- Patients should be warned about Intraoperative Floppy Iris Syndrome (IFIS) if they are scheduled for cataract surgery, as alpha-1 blockers can cause this complication. The ophthalmologist should be informed of terazosin use.
- Titration should be slow (weekly intervals) to minimize adverse effects and allow for adaptation.
- While food can delay absorption, it does not significantly affect the extent of absorption, so it can be taken with or without food, but consistency is key.
Alternative Therapies
- For Hypertension: Thiazide diuretics, ACE inhibitors, Angiotensin Receptor Blockers (ARBs), Calcium Channel Blockers (CCBs), Beta-blockers.
- 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 (e.g., TURP).
Cost & Coverage
Average Cost:
Typically low (generic) per 30 tablets
Generic Available:
Yes
Insurance Coverage:
Tier 1 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is 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 it's a good idea to check with your pharmacist. If you have any questions or concerns about this medication, don't hesitate to discuss them with 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 detailed information about the overdose, including the medication taken, the amount, and the time it occurred.