Tadalafil Side Effects Guide: Onset & Duration
Key Takeaways
- Most common: Headache (10% of users) - starts within 30 mins–2 hours
- Duration: Mild effects (e.g., flushing) last 4–12 hours; back pain up to 48 hours
- Serious reactions: Priapism (>4 hours), vision/hearing loss (seek help immediately)
- Risk factors: Heart disease, nitrate use, age >75
- Alcohol warning: Worsens dizziness (avoid excessive drinking)
While Tadalafil (Cialis®) is effective for erectile dysfunction and BPH, 1 in 10 users experience side effects. This guide explains their typical onset, duration, and when to seek emergency care—especially for high-dose (10mg/20mg) or daily-use (2.5mg/5mg) regimens.
Common Tadalafil Side Effects
Frequent (≥1 in 10 users)
- Headache Common
- Back pain Common
- Muscle aches Common
- Facial flushing Common
Less Common (1 in 100–1,000 users)
- Dizziness Uncommon
- Blurred vision Uncommon
- Prolonged erection (priapism)* Emergency
*Requires immediate treatment to prevent permanent damage.
When Do Tadalafil Side Effects Start?
| Side Effect | Typical Onset | Peak Intensity |
|---|---|---|
| Headache/Flushing | 30 mins–2 hours | 1–4 hours |
| Back pain | 2–8 hours | 12–24 hours |
| Priapism | Within 4 hours | Medical emergency |
| Vision loss | Immediate–48 hours | Requires urgent care |
How Long Do Tadalafil Side Effects Last?
| Side Effect | Duration | Management |
|---|---|---|
| Headache/Flushing | 4–12 hours | Hydration, rest |
| Back pain | 12–48 hours | OTC pain relievers |
| Priapism | >4 hours (emergency) | Seek ER immediately |
| Vision loss | Hours–permanent | Stop Tadalafil, call doctor |
Factors Affecting Duration
- Dosage: 20mg lasts longer than 10mg.
- Age: Elderly patients may metabolize slower.
- Health conditions: Liver/kidney disease prolongs effects.
Serious Side Effects Requiring Immediate Action
- Priapism: Erection lasting >4 hours
- Vision loss: Sudden decrease or blurred vision
- Allergic reaction: Swelling (face/throat), difficulty breathing
- Chest pain: Especially with nitrate use
Risk Factors for Serious Reactions
- Heart disease: Recent heart attack/stroke
- Nitrate use: Causes dangerous blood pressure drops
- NAION history: "Eye stroke" risk
Managing Tadalafil Side Effects
For Common Reactions
- Headache: Drink water, avoid caffeine.
- Back pain: Gentle stretching, warm compress.
- Flushing: Cool environment, hydrate.
Prevention Strategies
- Avoid alcohol: Worsens dizziness.
- Start low: Begin with 10mg (not 20mg).
- Daily dosing: 2.5mg/5mg reduces fluctuation.
FAQs
Can Tadalafil cause permanent vision loss?
While rare, NAION ("eye stroke") has been reported. Risk factors include:
- Pre-existing optic nerve issues
- Heart disease or diabetes
- Age >50
Stop Tadalafil and seek immediate help if vision changes occur.
Why does Tadalafil cause back pain?
Back pain (often lumbar) results from:
- Muscle relaxation: PDE5 inhibitors affect smooth muscle.
- Dose-dependent: More common with 20mg vs. 5mg.
Typically resolves within 48 hours. Contact your doctor if severe.
 | Authored by Nabeel |
Medical Content Manager
Nabeel is a co-founder, and medical content manager of Chemist Doctor. He works closely with our medical team to ensure the information is accurate and up-to-date.
 | Reviewed by Dr. Waqas (GMC:7928708) |
Medical Doctor
Dr. Waqas is a GMC-registered doctor at Chemist Doctor, specialising in general health. He balances clinical precision with cultural sensitivity.
 | Approved by Usman |
Medical Director
Usman is a co-founder, and medical director of Chemist Doctor. He leads the organisation's strategic vision, bridging clinical and operational priorities.
Review Date: 12 August 2025
Next Review: 14 February 2026
Published on: 11 August 2025
Last Updated: 12 August 2025
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