Can I take 90 and Nac together?
Drug interaction guide
Originally published 14 Mar 2026
Meets Patient’s editorial guidelines
- DownloadDownload
- Share
- Language
- Discussion
- Audio Version
There are no known significant interactions between N-acetylcysteine (NAC) and paracetamol (often referred to as '90' in certain contexts or misreadings of '500'mg tablets). In fact, NAC is the specific medical treatment used in hospitals to treat paracetamol overdose. When taken at normal, recommended doses, they do not interfere with each other.
In this article:
Continue reading below
Why this happens
NAC works by increasing the levels of glutathione in the liver. Glutathione is a substance that helps neutralise a toxic byproduct produced when the liver breaks down paracetamol. Because they work on the same pathway in a helpful way, there is no negative interaction.
What you should do
Back to contentsIt is safe to take these together at recommended doses. However, you must strictly limit or avoid alcohol when taking paracetamol, as the combination increases the risk of liver damage. Always follow the dosage instructions on the packaging.
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 Allerwel am and Calpol together?
There are no known harmful interactions between Allerwel AM and Calpol. It is generally safe to take these two medicines together as long as you follow the recommended doses for each.
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.