CBD and Ranitidine (e.g. Zantac, Sostril, Ranitic)

Taking CBD and ranitidine (Zantac, Sostril, Ranitic) together raises two main issues: ranitidine has been withdrawn in many countries because of NDMA contamination, and a clear clinical interaction between CBD and ranitidine has not been demonstrated so far. In practice, the focus is more on potentially additive side effects, liver and kidney health, and on possible alternatives such as famotidine.

Note: Ranitidine has been recalled or suspended in many countries due to NDMA contamination. Discuss with a doctor whether you should continue taking ranitidine and whether alternatives such as famotidine (H2 blocker) or proton pump inhibitors (PPIs) might be suitable.

CBD and ranitidine: what is important to know now?

The current situation on CBD and ranitidine is that a specific clinical interaction has not been established. As ranitidine is mainly excreted unchanged via the kidneys, a strong CYP‑mediated interaction with CBD is considered unlikely based on current knowledge. More relevant are additive effects such as tiredness and dizziness, as well as liver and kidney aspects – especially in older people and those taking multiple prescription medicines.

Mechanisms of action in brief

How does CBD work?

CBD interacts with the endocannabinoid system and other signalling pathways. It is being researched in relation to areas such as sleep, anxiety and pain; the strength of evidence varies by topic. Pharmacologically, CBD can inhibit liver enzymes such as CYP3A4 and CYP2C19 – a factor that should generally be considered when combining CBD with prescription medications that depend on these enzymes for metabolism.

H2 blockers (ranitidine, famotidine) and PPIs

Ranitidine and famotidine are H2 blockers that reduce stomach acid production. Ranitidine is largely excreted unchanged via the kidneys; extensive CYP‑mediated metabolism plays a lesser role. Famotidine shows a similar profile with very limited CYP involvement. Proton pump inhibitors (for example omeprazole, esomeprazole) are more extensively metabolised via CYP2C19/CYP3A4 – here, a theoretical interaction with CBD is more plausible than with H2 blockers.

Because of the ranitidine recall (NDMA), H2‑blocker alternatives (such as famotidine) or PPIs are now more commonly used in many countries. The choice between ranitidine, famotidine and PPIs – and any combination with CBD – should always be clarified with a doctor.

Possible interactions between CBD and H2 blockers

CYP enzymes, CBD metabolism and H2 blockers

There are no robust clinical data on a specific interaction between CBD and ranitidine. CBD can inhibit CYP3A4 and CYP2C19, which are important for the metabolism of many prescription medicines. However, as ranitidine is mainly excreted unchanged via the kidneys, a pronounced CYP‑mediated interaction between CBD and ranitidine or famotidine appears unlikely based on current knowledge.

For PPIs (which depend more strongly on CYP2C19/CYP3A4), the theoretical risk of a CBD drug interaction is higher than for H2 blockers, although clinical data on CBD with PPIs remain limited.

Additive side effects (tiredness, dizziness)

CBD may be associated with side effects such as tiredness, dizziness, dry mouth and occasional gastrointestinal symptoms. H2 blockers may cause headaches, dizziness or gastrointestinal symptoms. In combination, tiredness and dizziness may be more noticeable, particularly in older adults or those sensitive to these effects.

If unexplained symptoms occur when taking CBD with ranitidine, famotidine or PPIs, consider pausing or reducing the CBD dose and seek medical advice.

Liver and kidney function: particular caution

CBD has been associated with increased liver enzymes in some contexts, especially at higher doses or when taken together with other substances that may affect the liver. Ranitidine has only rarely been linked with liver reactions. As ranitidine is eliminated via the kidneys, kidney function is relevant for dosing and safety.

Older adults, people with liver or kidney conditions and those taking several medicines should be monitored closely by a doctor when combining CBD with ranitidine, famotidine or PPIs, as overall strain on the liver and kidneys may be higher.

“CBD × H2 blockers” – short overview

• CYP interaction with CBD: considered low/unclear for ranitidine/famotidine
• Additive tiredness/dizziness from CBD plus H2 blockers/PPIs: possible
• Liver: CBD may increase liver enzymes → blood tests may be useful in some cases
• Kidneys: relevant for ranitidine dose → medical review in kidney impairment

In practice: combining CBD with acid‑suppressing medicines

Timing, dosage and monitoring when using CBD and ranitidine

When combining CBD with ranitidine, famotidine or PPIs, many people use a careful “low & slow” approach:

• Start with a low CBD dose and increase gradually (for example weekly). Guidance: CBD dosage.
• Leave a gap of about 2–3 hours between CBD and H2 blockers/PPIs.
• Keep a simple record for 1–2 weeks (dose, timing, symptoms, side effects).
• If higher CBD doses are used or there is a history of liver issues, ask a doctor whether liver enzyme checks are appropriate.
• Watch for warning signs such as marked tiredness, strong dizziness, yellowing of the skin/eyes, severe nausea or persistent diarrhoea and seek medical assessment if these occur.

Ranitidine and alternatives (famotidine, PPIs): relevance for CBD

Is ranitidine still used? In many countries it is no longer routinely used because of the ranitidine recall due to NDMA. Alternatives include famotidine (H2 blocker) or PPIs.

For use together with CBD:

• Ranitidine: limited CYP metabolism; strong CBD CYP interactions are considered unlikely, but its NDMA‑related recall limits routine use.
• Famotidine: similar to ranitidine in that CYP involvement is low; the CBD interaction potential is also thought to be relatively low.
• PPIs (for example omeprazole): more strongly dependent on CYP2C19/CYP3A4; theoretical CBD interactions via these liver enzymes are more plausible.

The individual choice of acid‑suppressing medicine – including any switch from ranitidine to famotidine or a PPI – should be discussed with a doctor, especially in the context of reflux or heartburn and any planned CBD use.

In brief: side effects in combination

• CBD: often associated with mild effects (tiredness, dry mouth, dizziness, gastrointestinal symptoms); may be dose‑dependent; may affect liver values.
• H2 blockers/PPIs: headaches, dizziness, gastrointestinal complaints; H2 blockers are only rarely linked with liver‑related effects.
• Combination (CBD with ranitidine, famotidine or PPIs): tiredness and dizziness may be more pronounced, especially in sensitive individuals. If new or severe symptoms occur, consider pausing or reducing the CBD dose and seek medical advice.

Conclusion

• Ranitidine has been recalled due to NDMA contamination – discuss alternatives such as famotidine or PPIs with a doctor, especially if you are also using CBD.
• For CBD with H2 blockers (ranitidine/famotidine), strong CYP effects appear unlikely; additive side effects and liver and kidney function are the main considerations. For PPIs, theoretical CBD CYP interactions are more relevant, but evidence remains limited.
• In practice, a cautious approach is advisable: use “low & slow” CBD dosing, leave a 2–3 hour gap between CBD and acid‑suppressing medicines, keep a record of symptoms, and seek medical advice if warning signs occur.

Disclaimer: This article is for information purposes only and does not replace medical advice. Do not change medicines or dosages without consulting your doctor. No claims are made regarding the treatment or cure of illnesses.