PH1.10 | PH1.10 | Individualized Pharmacotherapy in Special Populations — SDL Guide — Summary & Reflection

KEY TAKEAWAYS

Special populations require individualised pharmacotherapy because standard doses were derived from studies in healthy adults — a definition that excludes neonates, elderly patients, pregnant women, and those with organ impairment.

Paediatrics: immature CYP450 (CYP3A4 matures by 6–12m) and UGT (glucuronidation mature by 6–18m) and immature renal function necessitate weight-based dosing and age-specific formulations. Grey baby syndrome (chloramphenicol) = immature glucuronidation. Tetracyclines and aspirin (Reye's syndrome) contraindicated in children.

Geriatrics: reduced renal GFR (estimate with Cockcroft-Gault — never trust creatinine alone in the elderly), reduced hepatic clearance, increased fat/decreased lean mass and TBW, reduced albumin, enhanced CNS/cardiovascular sensitivity. Polypharmacy drives interaction risk. Normal creatinine in an 80-year-old may mask GFR of 30–40 mL/min.

Pregnancy: organogenesis 3–8 weeks — highest teratogenesis risk. Warfarin contraindicated (crosses placenta — use heparin). Tetracyclines, retinoids, methotrexate, ACE inhibitors (2nd/3rd), NSAIDs (3rd) contraindicated. Paracetamol = safest analgesic. Penicillins/cephalosporins generally safe (Category B).

Lactation: milk:plasma ratio determines infant exposure. Paracetamol, ibuprofen, most beta-lactams safe; chloramphenicol, cytotoxics, lithium — avoid.

Renal impairment: use Cockcroft-Gault; metformin contraindicated eGFR < 30; aminoglycosides require TDM; NSAIDs worsen GFR — avoid. Hepatic impairment: Child-Pugh score; opioids and benzodiazepines accumulate; use LOT benzodiazepines; paracetamol dose-reduce in Child-Pugh C.

REFLECT

Think about a patient you know (or have read about in a case study) who belongs to a special population — a child, an elderly patient, or a pregnant woman. Was their drug therapy adjusted for their special pharmacokinetic characteristics? What are one or two drugs that would need specific reconsideration or dose adjustment for that patient? Write two or three sentences applying the principles from this SDL to that specific patient.