The Blood Flow Protocol uses prescription PDE-5 inhibitors—such as tadalafil, sildenafil, or vardenafil—to support healthy blood flow and sexual performance. These medications are well-established, but like all treatments, they may cause side effects for some individuals. Your clinician will determine whether this protocol is appropriate and safe for you based on your health history, symptoms, and medications.
Common Side Effects
Many side effects are related to how PDE-5 inhibitors affect blood vessels and smooth muscle. Common effects can include:
Mild headache
Facial flushing
Nasal congestion
Indigestion or stomach discomfort
Back or muscle aches (more common with tadalafil)
These effects are typically mild and often improve as your body adjusts.
Less Common Effects
Less common side effects may include:
Lightheadedness
Mild changes in vision (e.g., color tint or sensitivity)
Temporary dizziness
Slight increase in heart rate
These usually resolve on their own. If anything feels persistent or concerning, message your clinician for guidance.
Serious or Concerning Symptoms
Although uncommon, certain symptoms require immediate medical attention. Seek urgent care if you experience:
Chest pain
Severe dizziness or fainting
Sudden vision or hearing loss
Erection lasting more than four hours
Shortness of breath
Any symptom that feels severe or rapidly worsening
These are not typical treatment effects and require prompt evaluation.
Medication Interactions
Certain medications and health conditions may make PDE-5 inhibitors unsafe. These include:
Nitrates (often prescribed for chest pain)
Some blood pressure medications
Specific cardiovascular conditions
Certain eye or retinal conditions
Your clinician will review your medications and medical history to determine whether PDE-5 inhibitors are appropriate.
Lifestyle Factors That Influence Response
Some factors may impact how well the protocol works or how the medication feels, including:
Alcohol intake
Sleep quality
Stress levels
Hydration
Recent meals
Variability in response is normal. If you’re unsure what’s influencing your experience, your clinician can help review patterns.
Safety Monitoring
Your clinician will monitor:
Your symptoms
Your overall health status
Any side effects you report
How you respond to the prescribed medication
This helps ensure the treatment remains safe and effective over time.
When to Reach Out
Use your patient portal to message your clinician if you experience:
New or unexpected side effects
Gradual changes in how the medication works
Uncertainty about how lifestyle factors may be affecting your response
Questions about switching medications or adjusting your plan
Urgent issues should always be handled through emergency medical care.