drug-interaction-checker

name	drug-interaction-checker
description	Check for drug-drug interactions in veterinary patients with species-specific pharmacokinetic considerations. Use when a patient is on multiple medications or a new drug is being added.

Veterinary Drug Interaction Checker

Overview

Evaluate potential drug-drug interactions in veterinary patients. Drug interactions in animals differ from humans due to species-specific differences in hepatic metabolism (cytochrome P450 enzyme profiles), protein binding, renal clearance, and GI physiology. This skill checks for known interactions and flags combinations requiring dose adjustment or monitoring.

When to Use

• User asks whether two or more drugs can be given together to an animal
• User is adding a new medication to an existing regimen
• User asks about drug interactions in a specific species
• Keywords: interaction, combine, together, concurrent, polypharmacy, concomitant, contraindicated combination

Workflow

1. Identify all drugs in the patient's regimen (including supplements, nutraceuticals).
2. Confirm species (MANDATORY - metabolism pathways differ).
3. Check each drug pair for known interactions:
   • Pharmacokinetic interactions: Enzyme induction/inhibition, protein binding displacement, altered absorption
   • Pharmacodynamic interactions: Additive effects, synergism, antagonism
4. Classify severity:
   • Contraindicated: Must not be used together (e.g., MAOIs + serotonergic drugs)
   • Major: Significant risk requiring alternative therapy or intensive monitoring
   • Moderate: May require dose adjustment or monitoring
   • Minor: Minimal clinical significance but document
5. Provide management recommendation for each interaction found.

Common Veterinary Drug Interactions

• NSAIDs + corticosteroids: Increased GI ulceration risk (especially in dogs)
• ACE inhibitors + potassium-sparing diuretics: Hyperkalemia risk
• Phenobarbital + many drugs: CYP450 enzyme inducer; decreases levels of concurrent drugs
• Ketoconazole/itraconazole + many drugs: CYP450 inhibitor; increases levels of concurrent drugs
• Metoclopramide + opioids: Antagonistic effects on GI motility
• Fluoroquinolones + divalent cations (sucralfate, antacids): Chelation reduces absorption
• Cisapride + azole antifungals: QT prolongation risk
• Selegiline (Anipryl) + serotonergic drugs (tramadol, SSRIs, TCAs): Serotonin syndrome risk. Selegiline is an MAO-B inhibitor used for canine cognitive dysfunction. Do not combine with tramadol, fluoxetine, clomipramine, or amitriptyline. Allow 2-week washout between discontinuation and starting a serotonergic drug.
• Metronidazole + phenobarbital: Phenobarbital induces metronidazole metabolism; may require dose adjustment
• Cyclosporine + ketoconazole: Ketoconazole intentionally used to reduce cyclosporine dose (cost-saving strategy in vet practice, but requires monitoring)

Output Format

## Drug Interaction Check: [Species]

**Medications:** [List all drugs]

**Interactions found:**

1. [Drug A] + [Drug B]
   - **Severity:** [Contraindicated/Major/Moderate/Minor]
   - **Mechanism:** [How they interact]
   - **Clinical effect:** [What could happen]
   - **Management:** [What to do about it]

**No interactions found between:** [List non-interacting pairs]

Limitations

• Veterinary drug interaction databases are less comprehensive than human databases. Many interactions are extrapolated from human data.
• Individual patient factors (hepatic/renal disease, age) affect interaction risk.
• Nutraceuticals and supplements may have undocumented interactions.
• This skill identifies known interactions; absence of a listed interaction does not guarantee safety.