Pharmacist

Clinical Decision Support

Drug Interaction Checker

Reviewer: S Chishti – Pharmacist UK
Powered by AI + pharmacist logic
Enter medicine + medicine
Generic or brand names accepted.

Enter two medicines to see
interaction guidance.

Clinical Reading Guide

What Drug Interactions Mean

Written for patients and professionals
Use with the checker above
Always confirm important results

What is a drug interaction?

A drug interaction happens when one medicine changes how another medicine works. This may increase side effects, reduce benefit, or make treatment less predictable.

Why interactions matter

Some combinations are harmless. Others can lead to bleeding, drowsiness, kidney strain, heart rhythm problems, serotonin toxicity, or reduced control of long-term conditions.

Not only medicine versus medicine

Interactions can also involve alcohol, herbal products, supplements, food, smoking, or existing medical conditions. The full picture matters, not just two drug names.

Main types of interaction

Pharmacodynamic
Both medicines push the body in the same or opposite direction, such as extra bleeding or extra sedation.
Pharmacokinetic
One medicine changes absorption, breakdown, transport, or removal of the other, raising or lowering drug levels.
Duplicate therapy
Two products contain the same ingredient or similar action, causing unintended overdose or unnecessary risk.
Disease-related
A medicine may be suitable generally but risky for someone with asthma, ulcers, kidney disease, epilepsy, or pregnancy.

Common high-risk groups

  • Blood thinners
  • Antidepressants
  • Opioids and sedatives
  • NSAIDs and steroids
  • Heart rhythm medicines
  • Epilepsy medicines
  • Methotrexate and lithium

When extra care is needed

  • Starting a new prescription
  • Buying over-the-counter treatment
  • Adding vitamins or herbal products
  • Changing dose or stopping suddenly
  • Older age or multiple medicines
  • Kidney or liver disease
  • Pregnancy or breastfeeding

How to read checker results

Severity: High
Often means avoid, urgent review, or use only with clear specialist advice.
Severity: Moderate
Usually means caution, monitoring, timing advice, or dose adjustment may be needed.
Severity: Low
Usually small clinical impact, but still consider symptoms and personal risk factors.

Important reminder

A checker is a guide, not the final decision. The safest judgement depends on dose, timing, age, kidney function, liver function, medical history, and the reason the medicines were prescribed.

If the result shows caution or high severity, or if the patient has symptoms, speak to a pharmacist or prescriber before continuing.