Minipress 2mg Capsules
It is used to treat high blood pressure.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antihypertensive
Pharmacologic Class
Alpha-1 Adrenergic Blocker
Pregnancy Category
Category C
FDA Approved
Jun 1976
DEA Schedule
Not Controlled
Overview
What is this medicine?
Prazosin is a medication used to lower high blood pressure. It works by relaxing blood vessels, allowing blood to flow more easily. It can also help with symptoms of an enlarged prostate and is sometimes used for nightmares related to PTSD.
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 your medication as directed, with or without food. 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 your medication at room temperature, away from light and moisture. Keep it in a dry place, such as a closet or drawer, and avoid storing it in the bathroom. Keep all medications 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 instructed to do so. Instead, check with your pharmacist for guidance on proper disposal. You may also want to explore local drug take-back programs.
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. Do not take two doses at the same time or take extra doses to make up for a missed one.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. 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 your medication at room temperature, away from light and moisture. Keep it in a dry place, such as a closet or drawer, and avoid storing it in the bathroom. Keep all medications 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 instructed to do so. Instead, check with your pharmacist for guidance on proper disposal. You may also want to explore local drug take-back programs.
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. Do not take two doses at the same time or take extra doses to make up for a missed one.
Lifestyle & Tips
- Take the first dose at bedtime to minimize the risk of dizziness or fainting (first-dose syncope).
- Avoid sudden changes in position (e.g., standing up quickly from sitting or lying down) to prevent dizziness or lightheadedness.
- Avoid or limit alcohol consumption, as it can worsen dizziness and lower blood pressure.
- Stay hydrated, especially in hot weather or during exercise.
- Inform your doctor or dentist that you are taking prazosin before any surgery or dental procedures.
- Do not stop taking this medication suddenly without consulting your doctor, as it can lead to a sudden increase in blood pressure.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 1 mg orally 2-3 times daily. Maintenance: 6-15 mg/day in divided doses.
Dose Range:
1 - 40 mg
Condition-Specific Dosing:
hypertension:
Initial: 1 mg orally 2-3 times daily. Titrate slowly based on response, typically to 6-15 mg/day in divided doses. Max: 20 mg/day (some sources up to 40 mg/day for severe cases).
bph_off_label:
Initial: 0.5 mg orally at bedtime. Titrate slowly to 2-5 mg orally once daily or in divided doses.
ptsd_nightmares_off_label:
Initial: 1 mg orally at bedtime. Titrate slowly to 2-10 mg orally at bedtime.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established (limited off-label use for hypertension or specific conditions, e.g., 0.05-0.1 mg/kg/day divided, max 0.5 mg/kg/day or 20 mg/day)
Adolescent:
Not established (limited off-label use, similar to child dosing or adult initial dosing)
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment, but monitor response closely.
Moderate:
Start with lower initial dose (e.g., 0.5 mg) and titrate slowly.
Severe:
Start with lower initial dose (e.g., 0.5 mg) and titrate slowly; monitor closely for exaggerated hypotensive response.
Dialysis:
Prazosin is not significantly dialyzable. No supplemental dose needed after dialysis, but monitor for hypotension.
Hepatic Impairment:
Mild:
No specific adjustment, but monitor response closely.
Moderate:
Start with lower initial dose (e.5 mg) and titrate slowly; monitor for increased effects due to reduced metabolism.
Severe:
Start with lower initial dose (e.g., 0.5 mg) and titrate slowly; monitor closely for exaggerated hypotensive response and adverse effects.
Pharmacology
Mechanism of Action
Prazosin is a selective alpha-1 adrenergic receptor antagonist. It competitively blocks postsynaptic alpha-1 adrenergic receptors, leading to vasodilation of both arterioles and venules. This reduces peripheral vascular resistance and venous return to the heart, resulting in a decrease in blood pressure. It also relaxes smooth muscle in the prostate and bladder neck, which can improve urine flow in benign prostatic hyperplasia (BPH).
Pharmacokinetics
Absorption:
Bioavailability:
50-70%
Tmax:
2-3 hours
FoodEffect:
Food may delay absorption but does not significantly affect the extent of absorption.
Distribution:
Vd:
0.5 L/kg
ProteinBinding:
Approximately 95%
CnssPenetration:
Limited
Elimination:
HalfLife:
2-4 hours
Clearance:
Not available (primarily hepatic)
ExcretionRoute:
Primarily biliary/fecal (6-10% unchanged drug), minor renal excretion (5-11% unchanged drug)
Unchanged:
Approximately 6-11% (renal)
Pharmacodynamics
OnsetOfAction:
Approximately 30-60 minutes
PeakEffect:
Approximately 2-4 hours
DurationOfAction:
Approximately 6-10 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, including:
+ 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
Fast or abnormal heartbeat
A painful erection (hard penis) or an erection that lasts longer than 4 hours, which may occur even when you are not having sex. If left untreated, this can 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 or seek medical help:
Feeling dizzy, sleepy, tired, or weak
Headache
* Upset stomach
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, contact your doctor for medical advice. 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, including:
+ 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
Fast or abnormal heartbeat
A painful erection (hard penis) or an erection that lasts longer than 4 hours, which may occur even when you are not having sex. If left untreated, this can 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 or seek medical help:
Feeling dizzy, sleepy, tired, or weak
Headache
* Upset stomach
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, contact your doctor for medical advice. 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 (especially after the first dose or dose increase)
- Persistent lightheadedness
- Rapid or irregular heartbeat
- Swelling of ankles or feet
- Difficulty breathing
- Priapism (prolonged erection, rare but serious)
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 current 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, 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 current medications and health conditions. Never start, stop, or change the dose 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 24 hours after taking your first dose, as well as after any dose increase or 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, and exercise caution when navigating stairs.
As directed by your healthcare provider, regularly monitor your blood pressure.
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 scheduled to undergo cataract surgery or any other eye procedure, consult with your doctor beforehand.
Before using any 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, or certain natural products or aids, discuss their use with your doctor.
Additionally, talk to your doctor before consuming alcohol. In hot weather or during physical activity, be cautious and drink plenty of fluids to prevent dehydration.
If you are pregnant, planning to become pregnant, or are breastfeeding, inform your doctor. It is crucial to discuss the potential benefits and risks of this medication to both you and your baby.
To ensure your safety, avoid driving or engaging in activities that require alertness for 24 hours after taking your first dose, as well as after any dose increase or 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, and exercise caution when navigating stairs.
As directed by your healthcare provider, regularly monitor your blood pressure.
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 scheduled to undergo cataract surgery or any other eye procedure, consult with your doctor beforehand.
Before using any 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, or certain natural products or aids, discuss their use with your doctor.
Additionally, talk to your doctor before consuming alcohol. In hot weather or during physical activity, be cautious and drink plenty of fluids to prevent dehydration.
If you are pregnant, planning to become pregnant, or are breastfeeding, inform your doctor. It is crucial to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Profound hypotension (low blood pressure)
- Dizziness
- Drowsiness
- Syncope (fainting)
- Tachycardia (rapid heart rate)
What to Do:
Seek immediate medical attention. Call 911 or your local emergency number. For poison control, call 1-800-222-1222. Management typically involves supporting blood pressure with intravenous fluids and vasopressors if needed. Keep the patient in a supine position.
Drug Interactions
Major Interactions
- PDE5 inhibitors (e.g., sildenafil, tadalafil, vardenafil): Risk of severe hypotension.
- Other alpha-blockers (e.g., tamsulosin, doxazosin): Additive hypotensive effects.
Moderate Interactions
Minor Interactions
- Antidepressants (tricyclic, MAOIs): May enhance hypotensive effect.
- Levodopa: May enhance hypotensive effect.
Monitoring
Baseline Monitoring
Blood Pressure (sitting and standing)
Rationale: To establish baseline and assess for orthostatic hypotension before initiating therapy.
Timing: Prior to first dose
Heart Rate
Rationale: To establish baseline.
Timing: Prior to first dose
Routine Monitoring
Blood Pressure (sitting and standing)
Frequency: Regularly, especially during dose titration (e.g., daily for first few days, then weekly, then monthly)
Target: Individualized, typically <130/80 mmHg for hypertension
Action Threshold: Symptomatic hypotension (dizziness, syncope) or sustained SBP <90 mmHg or DBP <60 mmHg (adjust dose or discontinue)
Heart Rate
Frequency: Regularly, especially during dose titration
Target: 60-100 bpm
Action Threshold: Symptomatic bradycardia or tachycardia
Symptom Monitoring
- Dizziness
- Lightheadedness
- Syncope (especially with first dose or dose increases)
- Palpitations
- Headache
- Nausea
- Fatigue
- Nasal congestion
Special Patient Groups
Pregnancy
Prazosin is 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, 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 limited.
Second Trimester:
Potential for fetal harm based on animal data; human data limited.
Third Trimester:
Potential for fetal harm based on animal data; human data limited. Risk of neonatal hypotension if used close to delivery.
Lactation
Prazosin is excreted in small amounts into breast milk. The amount is generally considered low, and adverse effects on breastfed infants are unlikely. However, monitor the infant for signs of hypotension (e.g., lethargy, poor feeding). Considered L3 (moderately safe).
Infant Risk:
Low risk; monitor for drowsiness, poor feeding, or hypotension.
Pediatric Use
Safety and efficacy have not been established in pediatric patients. Use is generally off-label and requires careful consideration and monitoring by a specialist. Dosing is typically weight-based and titrated slowly.
Geriatric Use
Elderly patients may be more sensitive to the hypotensive effects of prazosin, particularly orthostatic hypotension. Start with a lower initial dose (e.g., 0.5 mg) and titrate slowly with careful monitoring of blood pressure and heart rate.
Clinical Information
Clinical Pearls
- **First-Dose Syncope:** Warn patients about the possibility of sudden and severe drops in blood pressure, especially with the first dose or when increasing the dose. Advise them to take the first dose at bedtime and to avoid activities requiring alertness for the first few hours.
- **Orthostatic Hypotension:** Emphasize slow position changes to minimize dizziness and falls.
- **Tolerance:** Tolerance to the antihypertensive effect may develop over time, requiring dose adjustments.
- **Priapism:** Although rare, advise male patients to seek immediate medical attention if they experience a prolonged erection (>4 hours).
- **Cataract Surgery:** Inform ophthalmologists about prazosin use prior to cataract surgery due to the risk of Intraoperative Floppy Iris Syndrome (IFIS).
Alternative Therapies
- Other alpha-1 blockers (e.g., doxazosin, terazosin - longer half-lives, once-daily dosing)
- Thiazide diuretics (e.g., hydrochlorothiazide)
- ACE inhibitors (e.g., lisinopril)
- Angiotensin Receptor Blockers (ARBs) (e.g., losartan)
- Beta-blockers (e.g., metoprolol)
- Calcium Channel Blockers (e.g., amlodipine)
- Combined alpha-beta blockers (e.g., labetalol, carvedilol)
Cost & Coverage
Average Cost:
$10 - $30 per 30 capsules (2mg generic)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (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 occurred.