One medication sometimes used to treat anxiety and trauma is prazosin (often known by the brand name Minipress). On this page, we’ve outlined some important information about the drug.

Without access to personalized care, anxiety can feel frustrating, and even overwhelming. For many people, taking medication is a significant step in allowing them to improve their mental health.

What is prazosin (Minipress)?

What is prazosin? How does it work?

Prazosin is an FDA-approved medication for treating high blood pressure. Additionally, it may sometimes be used off-label to treat post traumatic stress related nightmares, high blood pressure, congestive heart failure, benign prostatic hyperplasia (BPH), adrenal gland tumor, or Raynaud’s disease.

Prazosin belongs to a class of medications called alpha adrenergic blockers. Medications within this class help relax the blood vessels to improve blood flow in the body. As a result, a physically calming effect is experienced. This can potentially help with one’s mental wellbeing.

How is prazosin typically used?

Prazosin is available in 1 mg, 2 mg, and 5 mg oral tablets. Doctors often start their patients off on a low dose (typically 1 mg once at bedtime) and then may gradually increase the dosage over time, depending on the patients’ needs. This helps the patient’s body adjust to the medication, thus preventing negative reactions associated with taking too much medication too quickly.

It may take some time to begin seeing the full effects of taking prazosin. Thus, to ensure that you are getting the full benefits, take your medicine on a consistent basis, per your doctor’s instructions.

Do not stop taking prazosin without talking to your doctor, because stopping the medication too quickly can lead to a negative reaction.  When your doctor sees that you are ready to stop taking this medication, they will gradually lower your dose over several weeks. This is a process often called “tapering”.

What are some possible side effects?

Some common side effects of prazosin include:

• Tiredness 
• Sleepiness
• Weakness
• Dizziness 
• Fainting
• Headache
• Nausea, vomiting, diarrhea, constipation

Some serious (but uncommon) side effects include:

• Rash
• Chest pain
• Itching
• Hives
• Irregular heartbeat
• Changes in mood
• Painful erection of the penis that lasts for hours 

Call 911 or seek emergency care if you notice any severe side effects. 

Why do these side effects occur? 

Any medication can potentially lead to side effects, and a person’s likelihood of having side effects depends on many factors, including age, lifestyle, and the type of medication itself. Side effects may occur because drugs often have broad or poorly targeted effects, or the drug target itself may have many downstream effects on the body. 

Prazosin relaxes the blood vessels, increasing blood flow throughout the body. As a result, this increased blood flow can have impacts on other parts of the body, manifesting into what we know as side effects. 

Many non-serious side effects of mental health medications like prazosin go away after a few weeks as your body adjusts to the medication. However, if a side effect persists, is intolerable, or severely hinders your ability to go about your daily life, talk to your doctor. This may indicate that the medication is not a good fit. 

How do your genes relate to prazosin? 

Genetics can affect your body’s response to medication. Your liver is primarily responsible for breaking down Prazosin. Sometimes, a person’s genetics can have an impact on their liver function which leads them to metabolize the medication differently than others. 

Some people might be slow metabolizers for prazosin. Being a slow metabolizer means your body will break down the medication more slowly than others, which means the drug sticks around in your body for longer than average and may lead to side effects. For slow metabolizers, a doctor might opt to prescribe a different medication or prescribe a lower dosage. Also, prazosin can also affect the way your body breaks down some other medications.

One way to predict whether you’ll have a positive outcome while taking prazosin is by taking a genetic test to determine what genetic variations you have and how they may affect medication metabolization. Your DNA can help your doctor rule out less suitable medications and make more informed decisions so that you can get better, faster.

Special Precautions

• Prazosin can make you feel lightheaded and dizzy. You should not drive or handle any heavy machinery while taking the medication especially if your dose was recently increased.
• Inform your doctor before taking any other medication or supplements alongside prazosin to prevent any unwanted drug interactions. 
• Inform your doctor that you are taking prazosin before eye surgery
• Prazosin can cause prolonged or painful erection (priapism). If you experience this, it is important to seek medication attention immediately. 
• While taking prazosin, it is important to control the amount of alcohol you drink. 
• Pregnant and breastfeeding mothers should talk with their doctors, so that they can confirm that the benefits of taking prazosin outweighs the risks associated with the medication. 
• If you are visiting a new doctor, it is important to inform them that you are taking prazosin before undergoing any treatment or taking any new medication. 

If you show signs of an allergic reaction to prazosin (hives, difficulty breathing, rash, swelling), call 911 or go to the nearest emergency department.

Some medications, vitamins, and herbs may interfere with how prazosin works. Make sure to tell your doctor about all other medications you are taking before starting prazosin to avoid negative interactions. For full details, see the FDA’s full list of precautions. 

Looking to find the right medication for your mental health? Join Prairie today to connect to expert providers and affordable medication options.