contraindication-checker

# Veterinary Contraindication Checker ## Overview Systematic contraindication checking for veterinary drug therapy. Goes beyond drug-drug interactions (see `drug-interaction-checker`) to evaluate patient-specific factors that may make a drug unsafe: species, breed genetics, organ dysfunction, pregnancy, age extremes, and concurrent disease states. ## When to Use - Before recommending any drug therapy in a veterinary patient - When a patient has known organ dysfunction (renal, hepatic, cardiac) - When a patient is pregnant, lactating, or neonatal - When breed-specific drug sensitivities may apply - Keywords: contraindication, safe to use, can I give, renal dose, hepatic dose, pregnant, breeding, puppy, kitten, geriatric ## Contraindication Categories ### Species Contraindications See `lethal-variance-detection` skill. Some drugs are absolutely contraindicated in certain species regardless of patient status. ### Breed/Genetic Contraindications - **MDR1 mutation (ABCB1):** Ivermectin (high dose), loperamide, acepromazine (use lower dose), vincristine, doxorubicin -- affected breeds: Collie, Australian Shepherd, Shetland Sheepdog, Old English Sheepdog, and crosses - **Greyhounds/Sighthounds:** Prolonged thiopental recovery, different propofol pharmacokinetics, lower normal reference ranges for some lab values - **Brachycephalic breeds:** Higher anesthesia risk, avoid heavy sedation protocols, caution with opioid-induced respiratory depression ### Organ Function Contraindications - **Renal insufficiency:** Adjust or avoid nephrotoxic drugs (aminoglycosides, cisplatin, NSAIDs). Reduce doses of renally excreted drugs. - **Hepatic insufficiency:** Avoid hepatotoxic drugs (ketoconazole, azathioprine at standard doses). Reduce doses of hepatically metabolized drugs. - **Cardiac disease:** Avoid negative inotropes in heart failure patients. Caution with fluid-loading drugs. - **GI disease:** Consider route of administration; oral drugs may have unpredictable absorption. ### Life Stage Contraindications - **Neonatal/Pediatric:** Many drugs lack pediatric dosing data. Immature hepatic and renal function affects clearance. Fluoroquinolones avoid in growing animals (cartilage damage). - **Geriatric:** Reduced organ reserve. Start low, go slow. More susceptible to adverse effects. - **Pregnant/Lactating:** Many drugs are teratogenic or excreted in milk. Griseofulvin is teratogenic in cats. Methotrexate, retinoids are contraindicated. ### Disease State Contraindications - **Seizure history:** Avoid drugs that lower seizure threshold (fluoroquinolones, tramadol in some patients) - **Bleeding disorders:** Avoid NSAIDs and drugs affecting platelet function - **GDV/GI obstruction:** Oral medications may not be absorbed; avoid prokinetics if mechanical obstruction ## Workflow 1. List all patient parameters: species, breed, age, weight, reproductive status, known organ dysfunction, concurrent diseases, current medications. 2. For each proposed drug, check against all applicable contraindication categories. 3. If a contraindication is found, classify severity: - **Absolute:** Do not use under any circumstances - **Relative:** Use only if benefit clearly outweighs risk, with monitoring - **Dose adjustment:** Drug may be used at modified dose or frequency 4. Suggest alternatives when a drug is contraindicated. ## Limitations - Contraindication data is most complete for dogs and cats. Exotic species data is limited. - Clinical judgment may override relative contraindications when no suitable alternative exists. - New contraindications are discovered through post-market surveillance and case reports.