Drug interactions
Cimetidine + Dabrafenib
Severity: Moderate
Cimetidine and Dabrafenib: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Dabrafenib solubility falls as gastric pH rises, so acid-reducing drugs such as H2 blockers may reduce its absorption. Lower exposure could reduce antitumor efficacy.
What this interaction means in plain words
Cimetidine and Dabrafenib can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Cimetidine belongs to Gastrointestinal Tract; Dabrafenib belongs to Oncology.
Why it happens
Cimetidine increases gastric pH, reducing dissolution and absorption of oral dabrafenib.
What to do
Avoid unnecessary acid suppression, or monitor for loss of tumor response. If acid suppression is needed, discuss alternatives with the oncology team.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Other interactions of Dabrafenib
Frequently asked questions
Can I take Cimetidine with Dabrafenib?
MediHelp rates the interaction as moderate. Cimetidine and Dabrafenib can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Dabrafenib solubility falls as gastric pH rises, so acid-reducing drugs such as H2 blockers may reduce its absorption. Lower exposure could reduce antitumor efficacy.
How serious is the interaction between Cimetidine and Dabrafenib?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid unnecessary acid suppression, or monitor for loss of tumor response. If acid suppression is needed, discuss alternatives with the oncology team.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine page.
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