Drug interactions
Linagliptin-metformin + Promethazine
Severity: Minor
Linagliptin-metformin and Promethazine: 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
Promethazine, a phenothiazine, can raise blood glucose in some patients and may weaken the glucose-lowering effect of metformin. The effect is usually modest. Glycemic control may drift when it is started and hypoglycemia may occur when it is stopped.
What this interaction means in plain words
Linagliptin-metformin and Promethazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Linagliptin-metformin belongs to Endocrine; Promethazine belongs to Respiratory.
Why it happens
Phenothiazines may impair insulin secretion and glucose tolerance, which opposes the effect of antidiabetic agents (pharmacodynamic antagonism).
What to do
Check blood glucose more often when promethazine is started or stopped, especially with prolonged use. Adjust the antidiabetic regimen only if control changes.
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 Linagliptin-metformin
Other interactions of Promethazine
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Frequently asked questions
Can I take Linagliptin-metformin with Promethazine?
MediHelp rates the interaction as minor. Linagliptin-metformin and Promethazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Promethazine, a phenothiazine, can raise blood glucose in some patients and may weaken the glucose-lowering effect of metformin. The effect is usually modest. Glycemic control may drift when it is started and hypoglycemia may occur when it is stopped.
How serious is the interaction between Linagliptin-metformin and Promethazine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check blood glucose more often when promethazine is started or stopped, especially with prolonged use. Adjust the antidiabetic regimen only if control changes.
What other medicines interact with Linagliptin-metformin?
MediHelp also lists interactions of Linagliptin-metformin with, for example, Apalutamide, Carbamazepine, Contrast media. The full list is on the Linagliptin-metformin page.
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