Terazosin 2mg 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 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 and the muscles in the prostate and bladder, which helps to lower blood pressure and improve urine flow.
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 it even if you feel well, unless your doctor or healthcare provider tells you to stop.
Storing and Disposing of Your Medication
Store this medication at room temperature, away from light and moisture. Keep it in a dry place, avoiding storage in a bathroom. Ensure all medications are kept in a safe location, out of 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 disposal, consult your pharmacist. You may also want to check if there are drug take-back programs available in your area.
Missing 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. Avoid taking two doses at the same time or taking 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 it even if you feel well, unless your doctor or healthcare provider tells you to stop.
Storing and Disposing of Your Medication
Store this medication at room temperature, away from light and moisture. Keep it in a dry place, avoiding storage in a bathroom. Ensure all medications are kept in a safe location, out of 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 disposal, consult your pharmacist. You may also want to check if there are drug take-back programs available in your area.
Missing 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. Avoid taking two doses at the same time or taking 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 (first-dose phenomenon).
- 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 worsen dizziness and low blood pressure.
- Stay hydrated, especially in hot weather or during exercise, to help prevent dehydration and low blood pressure.
- For BPH, continue regular follow-up with your doctor to monitor symptoms and prostate health.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial 1 mg orally once daily at bedtime; titrate slowly based on response and tolerability. Common maintenance doses are 2 mg, 5 mg, or 10 mg once daily. Max 20 mg/day.
Dose Range:
1 - 20 mg
Condition-Specific Dosing:
Benign Prostatic Hyperplasia (BPH):
Initial 1 mg orally once daily at bedtime. May increase to 2 mg, 5 mg, or 10 mg once daily at 4-7 day intervals to achieve desired response. Max 20 mg/day.
Hypertension:
Initial 1 mg orally once daily at bedtime. May increase to 2 mg, 5 mg, or 10 mg once daily at 4-7 day intervals to achieve desired blood pressure control. 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.
Dialysis:
Not significantly removed by dialysis; no specific supplemental dose needed.
Hepatic Impairment:
Mild:
Use with caution; consider lower initial doses and slower titration.
Moderate:
Use with caution; consider lower initial doses and slower titration. Monitor closely for adverse effects.
Severe:
Use with caution; consider lower initial doses and slower titration. Monitor closely for adverse effects. Not recommended in severe impairment due to lack of data.
Pharmacology
Mechanism of Action
Terazosin is a selective alpha-1 adrenergic receptor antagonist. It blocks alpha-1 receptors in the smooth muscle of the prostate, bladder neck, and prostatic capsule, leading to relaxation of these muscles and improved urine flow in BPH. In hypertension, it causes vasodilation by blocking alpha-1 receptors in peripheral arterioles and venules, leading to a reduction in peripheral vascular resistance and blood pressure.
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:
Approximately 60% via feces and 40% via urine.
Unchanged:
Approximately 10% (urine)
Pharmacodynamics
OnsetOfAction:
Within 1 hour (for blood pressure lowering)
PeakEffect:
2-3 hours (for blood pressure lowering)
DurationOfAction:
Up to 24 hours
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Attention Immediately
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 medical help right away:
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 (priapism) or an erection that lasts longer than 4 hours, which can occur even when not engaging in sexual activity. If left untreated, this condition may lead to permanent sexual dysfunction.
Other Possible Side Effects
As with any medication, you may experience side effects. While many people do not have any side effects or only minor 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 resolve, contact your doctor or seek medical help:
Dizziness
Drowsiness
Fatigue
Weakness
Nasal congestion
Headache
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 medical help right away:
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 (priapism) or an erection that lasts longer than 4 hours, which can occur even when not engaging in sexual activity. If left untreated, this condition may lead to permanent sexual dysfunction.
Other Possible Side Effects
As with any medication, you may experience side effects. While many people do not have any side effects or only minor 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 resolve, contact your doctor or seek medical help:
Dizziness
Drowsiness
Fatigue
Weakness
Nasal congestion
Headache
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 lightheadedness
- Fainting (syncope)
- Rapid or pounding heartbeat
- Chest pain
- Swelling in the ankles or feet
- Persistent headache
- Blurred vision
- 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, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This information will help your doctor and pharmacist assess potential interactions between this medication and other substances you are taking.
* Any existing health problems, as this medication may interact with certain conditions.
To ensure your safety, it is crucial to verify that it is safe to take this medication with all your other medications and health conditions. Do not initiate, discontinue, or modify 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.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This information will help your doctor and pharmacist assess potential interactions between this medication and other substances you are taking.
* Any existing health problems, as this medication may interact with certain conditions.
To ensure your safety, it is crucial to verify that it is safe to take this medication with all your other medications and health conditions. Do not initiate, discontinue, or modify 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.
When starting this medication, or after any increase in dose, or if you restart it after stopping, do not operate a vehicle or engage in activities that require alertness for 12 hours. Before driving or performing other tasks, make sure you understand how this medication affects you.
To minimize the risk of dizziness or fainting, stand up slowly after sitting or lying down, and exercise caution 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, 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, and certain natural products or aids.
Discuss alcohol consumption with your doctor before drinking 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, consult with your doctor to discuss the potential benefits and risks to you and your baby.
When starting this medication, or after any increase in dose, or if you restart it after stopping, do not operate a vehicle or engage in activities that require alertness for 12 hours. Before driving or performing other tasks, make sure you understand how this medication affects you.
To minimize the risk of dizziness or fainting, stand up slowly after sitting or lying down, and exercise caution 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, 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, and certain natural products or aids.
Discuss alcohol consumption with your doctor before drinking 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, consult with your doctor to discuss the potential benefits and risks to you and your baby.
Overdose Information
Overdose Symptoms:
- Profound hypotension (extremely low blood pressure)
- Dizziness
- Fainting (syncope)
- Tachycardia (rapid heart rate)
- Shock
What to Do:
In case of overdose, immediately contact a poison control center or emergency medical services. Call 1-800-222-1222 for poison control. Management typically involves supporting cardiovascular function, elevating the patient's legs, and administering vasopressors if necessary. Volume expansion may also be considered.
Drug Interactions
Major Interactions
- PDE5 inhibitors (e.g., sildenafil, tadalafil, vardenafil, avanafil): Concomitant use can lead to additive hypotensive effects, potentially causing symptomatic hypotension.
- Other alpha-blockers (e.g., prazosin, doxazosin, tamsulosin): Increased risk of hypotension.
Moderate Interactions
- Antihypertensive agents (e.g., beta-blockers, diuretics, ACE inhibitors, calcium channel blockers): May have additive hypotensive effects, requiring dose adjustment of either agent.
- Nitrates: Increased risk of hypotension.
Monitoring
Baseline Monitoring
Blood Pressure (BP)
Rationale: To establish baseline and assess for orthostatic hypotension before initiating therapy.
Timing: Prior to first dose and before any dose increase.
International Prostate Symptom Score (IPSS) or AUA Symptom Score
Rationale: To quantify baseline BPH symptoms and track treatment efficacy.
Timing: Prior to initiation of therapy for BPH.
Routine Monitoring
Blood Pressure (BP)
Frequency: Regularly, especially during initial titration and after dose increases. At least weekly during titration, then periodically (e.g., monthly, quarterly) once stable.
Target: Individualized, typically <130/80 mmHg for hypertension; monitor for symptomatic hypotension.
Action Threshold: Symptomatic hypotension (dizziness, lightheadedness, syncope); sustained systolic BP <90 mmHg or significant orthostatic drop (>20 mmHg systolic or >10 mmHg diastolic).
Orthostatic Blood Pressure
Frequency: During initial titration and after dose increases, especially if patient reports dizziness or lightheadedness. Periodically thereafter.
Target: No significant orthostatic drop.
Action Threshold: Significant orthostatic drop (e.g., >20 mmHg systolic or >10 mmHg diastolic) with symptoms.
BPH Symptoms (IPSS/AUA Score)
Frequency: Periodically (e.g., every 3-6 months) to assess treatment efficacy.
Target: Reduction in symptom score.
Action Threshold: Lack of symptomatic improvement or worsening of symptoms.
Symptom Monitoring
- Dizziness
- Lightheadedness
- Syncope (fainting), especially with first dose or dose increases
- Palpitations
- Headache
- Nasal congestion
- Fatigue
- Edema
Special Patient Groups
Pregnancy
Terazosin is classified as Pregnancy Category C. It 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, but there are no adequate and well-controlled studies in pregnant women.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm based on animal data; human data lacking.
Second Trimester:
Potential for fetal harm based on animal data; human data lacking.
Third Trimester:
Potential for fetal harm based on animal data; human data lacking. Risk of hypotension in mother which could affect placental perfusion.
Lactation
It is not known whether terazosin is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from terazosin, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Infant Risk:
Risk unknown; potential for hypotension or other adverse effects in the infant. Caution advised.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Terazosin is not indicated for use in children.
Geriatric Use
Geriatric patients may be more sensitive to the hypotensive effects of terazosin, particularly the first-dose phenomenon. Start with the lowest dose (1 mg) and titrate slowly. Monitor blood pressure and orthostatic changes closely.
Clinical Information
Clinical Pearls
- The 'first-dose phenomenon' (marked 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 some patients.
- Patients should be advised to avoid activities requiring mental alertness for at least 12 hours after the first dose or any dose increase.
- Orthostatic hypotension is a common side effect; educate patients on slow position changes.
- Unlike some other alpha-1 blockers, terazosin does not significantly affect PSA levels, which is beneficial for prostate cancer screening.
Alternative Therapies
- Other alpha-1 adrenergic blockers (e.g., doxazosin, prazosin, tamsulosin, alfuzosin, silodosin)
- 5-alpha reductase inhibitors (e.g., finasteride, dutasteride) for BPH
- PDE5 inhibitors (e.g., tadalafil) for BPH
- Antihypertensive agents from other classes (e.g., ACE inhibitors, ARBs, beta-blockers, calcium channel blockers, diuretics) for hypertension
- Surgical interventions for BPH (e.g., TURP)
Cost & Coverage
Average Cost:
Varies widely, typically $10-$50 per 30 capsules (2mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 (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 your 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 taken, the amount, and the time it happened.