Drug interactions
Morphine + Ritonavir
Severity: Minor
Morphine and Ritonavir: minor 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
Morphine is cleared mainly by glucuronidation and not significantly by CYP2D6, so CYP inhibition by ritonavir is not the key issue. Ritonavir may inhibit P-glycoprotein and can induce glucuronidation, which may alter morphine exposure in either direction, and the effect is unpredictable.
What this interaction means in plain words
Morphine and Ritonavir have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Morphine belongs to Musculoskeletal; Ritonavir belongs to Anti Virals.
Why it happens
Possible effects on P-glycoprotein transport and UGT induction by ritonavir; net effect on morphine is not well established.
What to do
Monitor analgesic response and signs of opioid toxicity or withdrawal, and adjust the morphine dose according to clinical effect.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Morphine
- Alvimopan + Morphine Contraindicated
- Isocarboxazid + Morphine Contraindicated
- Morphine + Olanzapine / samidorphan Contraindicated
- Morphine + Phenelzine Contraindicated
- Morphine + Tranylcypromine Contraindicated
- Alfentanil + Morphine Major
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Morphine with Ritonavir?
MediHelp rates the interaction as minor. Morphine and Ritonavir have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Morphine is cleared mainly by glucuronidation and not significantly by CYP2D6, so CYP inhibition by ritonavir is not the key issue. Ritonavir may inhibit P-glycoprotein and can induce glucuronidation, which may alter morphine exposure in either direction, and the effect is unpredictable.
How serious is the interaction between Morphine and Ritonavir?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor analgesic response and signs of opioid toxicity or withdrawal, and adjust the morphine dose according to clinical effect.
What other medicines interact with Morphine?
MediHelp also lists interactions of Morphine with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Morphine page.
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