Onset Time of Lidocaine Spray
Lidocaine spray typically begins working within 2-5 minutes of application, with maximum effect achieved around 4-5 minutes after application. 1, 2
Onset Time by Application Site
Different mucosal surfaces show varying onset times for lidocaine spray:
- Oral mucosa: Maximum hypoalgesia reached after 4-5 minutes 2
- Genital mucosa: Analgesia achieved in an average of 2.7 minutes (range: 1-4 minutes) 3
- Skin (non-mucosal): Significant anesthetic effect in approximately 25-30 minutes, with optimal effects between 35-40 minutes 4
Duration of Action
The duration of lidocaine spray's effect also varies by application site:
- Oral mucosa: Hypoalgesic effect lasts approximately 14 minutes, with optimal procedure window between 3-8 minutes after application 2
- Genital mucosa: Effect lasts an average of 29.7 minutes (range: 12-45 minutes) 3
- Topical lidocaine preparations: Duration of approximately 30-60 minutes 1
Clinical Applications
The Difficult Airway Society guidelines recommend lidocaine spray for awake tracheal intubation, noting its rapid onset (2-5 minutes) and relatively short duration (30-60 minutes) 1.
For pediatric procedures, topical lidocaine preparations can be used for:
- Intravenous line placement
- Lumbar puncture
- Abscess drainage
- Joint aspiration 1
Important Considerations
- Complete analgesia is not always achieved with lidocaine spray alone 2
- Individual variation exists in response to lidocaine spray, with some patients experiencing shorter duration of effect 3
- Application technique matters: Occlusion can triple serum lidocaine levels, potentially increasing risk of toxicity 5
- Initial application may cause discomfort: The spray can produce a painful, smarting sensation that typically resolves within 15-30 seconds 3
Safety Considerations
- Maximum safe dose of lidocaine should not exceed 9 mg/kg lean body weight for topical applications 6
- Early signs of toxicity include circumoral numbness, facial tingling, light-headedness, and tinnitus 6
- Lidocaine spray should not be used concurrently with other local anesthetic interventions 6
Practical Recommendations
For optimal results when using lidocaine spray:
- Allow 4-5 minutes after application before performing painful procedures on oral mucosa 2
- Wait at least 4 minutes after application before performing procedures on genital mucosa 3
- For skin applications, allow 25-30 minutes for significant effect, with optimal anesthesia at 35-40 minutes 4
- Consider that 8% lidocaine spray produces cutaneous anesthesia faster than lidocaine patches 7
When timing is critical, remember that lidocaine spray works much faster on mucosal surfaces (2-5 minutes) than on intact skin (25-30 minutes).