Serious Side Effects of Cialis: When to Seek Urgent Medical Help
Serious side effects from Cialis (tadalafil) are rare, but when they occur they require immediate action. This page explains which symptoms are emergencies, why they happen, and exactly what to do if they occur.
Priapism (Painful Erection Lasting Over 4 Hours)
What it is
Priapism is a prolonged, often painful erection that does not go away after sexual activity.
Why it’s dangerous
- Trapped blood can damage penile tissue
- Delayed treatment can lead to permanent erectile damage
What to do
- Seek emergency medical care immediately
- Do not wait for it to resolve on its own
- Do not take another dose or attempt self-treatment
This risk is higher with incorrect dosing or combining ED medicines.
Chest Pain, Fainting, or Severe Dizziness
What it may indicate
- Dangerous drop in blood pressure
- Heart-related stress during sexual activity
- Severe interaction with contraindicated medicines (especially nitrates)
What to do
- Stop sexual activity immediately
- Call emergency services
- Tell healthcare providers you have taken tadalafil
This is why Cialis is not suitable for some heart conditions.
Sudden Vision Loss (One or Both Eyes)
What it may be
Rare cases of non-arteritic anterior ischemic optic neuropathy (NAION) have been reported with PDE5 inhibitors.
Warning signs
- Sudden decrease or loss of vision
- Often painless
- Can affect one or both eyes
What to do
- Stop taking Cialis
- Seek urgent medical attention
- Do not restart the medicine unless a clinician confirms safety
Vision-related risks are especially relevant in those with pre-existing eye conditions.
Sudden Hearing Loss or Ringing in the Ears
What it may include
- Sudden hearing reduction or loss
- Ringing (tinnitus)
- Dizziness accompanying hearing changes
What to do
- Stop taking Cialis
- Seek urgent medical evaluation
Do not assume this will resolve without assessment.
Severe Allergic Reaction (Anaphylaxis)
Possible symptoms
- Swelling of face, lips, tongue, or throat
- Difficulty breathing or swallowing
- Severe rash or hives
- Rapid heartbeat or collapse
What to do
- Call emergency services immediately
- Do not take another dose
This is a medical emergency regardless of dose or timing.
Severe Low Blood Pressure (Hypotension)
How it can happen
- Combining Cialis with nitrates
- Combining with certain alpha-blockers
- Excessive alcohol use
- Dehydration
Warning signs
- Extreme dizziness
- Fainting
- Blurred vision
- Confusion
What to do
- Sit or lie down immediately
- Seek urgent medical advice if symptoms persist or worsen
After an Emergency: What to Tell the Doctor
Always inform healthcare providers:
- You took tadalafil (Cialis)
- The dose
- When you took it
- Any other medicines or substances used (including alcohol)
This information directly affects safe treatment decisions.
What Serious Side Effects Are NOT
To avoid unnecessary panic:
- Mild headache, flushing, or nasal congestion are not emergencies
- Temporary muscle or back pain is not usually dangerous
Key Takeaways
- Serious side effects are rare but urgent
- Priapism, chest pain, vision/hearing loss require immediate action
- Never ignore severe dizziness or fainting
- Always disclose Cialis use in emergencies
- Correct dosing and interaction avoidance reduce risk