Can I take 50 and Lidocaine grunenthal together?
Drug interaction guide
Originally published 14 Mar 2026
Meets Patient’s editorial guidelines
- DownloadDownload
- Share
- Language
- Discussion
- Audio Version
There is no known interaction between 5-HTP (often referred to as '50' in supplement contexts) and Lidocaine Grunenthal (a medicated plaster or local anaesthetic).
In this article:
Continue reading below
Why this happens
5-HTP is a precursor to serotonin and primarily affects the central nervous system. Lidocaine Grunenthal works locally to numb pain by blocking sodium channels in the nerves. These two substances work through different pathways in the body and do not interfere with each other's metabolism or effects.
What you should do
Back to contentsYou can use these two products together. However, if you are using Lidocaine Grunenthal (the plaster) for post-herpetic neuralgia (nerve pain after shingles), ensure you follow the specific application instructions provided by your doctor. If you experience any unusual side effects, such as extreme drowsiness or skin irritation, contact your healthcare provider.
Continue reading below
Using other medicines
Back to contentsTaking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.
Disclaimer
This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.
Patient picks for Drug interactions

Treatment and medication
Can I take Codeine and Magnesium together?
Taking magnesium and codeine together can lead to increased drowsiness and may cause constipation. Magnesium can also slightly interfere with how your body absorbs codeine if taken at the exact same time.

Treatment and medication
Can I take Ashwagandha and Vitamin d2 together?
There are no known significant interactions between ashwagandha and vitamin D2 (ergocalciferol). It is generally considered safe to take these two supplements together.
Article history
The information on this page is written and peer reviewed by qualified clinicians.
14 Mar 2026 | Originally published

Ask, share, connect.
Browse discussions, ask questions, and share experiences across hundreds of health topics.

Feeling unwell?
Assess your symptoms online for free
Sign up to the Patient newsletter
Your weekly dose of clear, trustworthy health advice - written to help you feel informed, confident and in control.
By subscribing you accept our Privacy Policy. You can unsubscribe at any time. We never sell your data.