Introduction to Specialised Population PDF

Introduction to Specialised Population Adliah Mhd Ali (PhD, RPh) NFNF3932 Faculty of Pharmacy Universiti Kebangsaan Malaysia  What is Specialised Population? ◻ The definition of “special population” exists to provide enhanced...

Introduction to Specialised Population Adliah Mhd Ali (PhD, RPh) NFNF3932 Faculty of Pharmacy Universiti Kebangsaan Malaysia  What is Specialised Population? ◻ The definition of “special population” exists to provide enhanced awareness of the vulnerabilities. ◻ Special populations include women, children (pediatrics), the elderly (geriatrics), pregnancy (obstetrics) and patients with concurrent disease states.  Special Population Women ❑ Variability in drug response and disease progression between men and women. ❑ Disease progression: Manifest differently between men and women. ❑ Estrogen levels: Affect altered drug pharmacokinetics affecting gastric emptying. ❑ Estrogen effect: Change drug transit times in healthy non-pregnant women, pregnancy and menopause.  Special Population Women ❑ Differences in body composition: Influence absorption and distribution of drugs. ❑ Women: Lower body weight, higher percentage body fat & lower plasma volumes than men.  Special Population Women ❑ Pregnant women ❑ Medication during pregnancy esp during first trimester. ❑ Very few studies examined drug dosing and consequences: Physiologic changes and trans- placental factors during pregnancy. ❑ Rate of drug absorption: Nausea & vomiting, changes in gastric volume and pH, drug metabolizing enzyme or altered GI motility.  Special Population Women ❑ Pregnant women ❑ Pharmacokinetics & pharmacodynamics: Changes in weight and body composition, pregnancies (e.g. twins, triplets), increased blood volume, and abrupt changes in behaviours. ❑ Kidneys and liver are also affected.  Special Population Women ❑ Pregnant women ❑ Fetal vulnerability to drug pharmacodynamics and toxicity e.g thalidomide in the 1st trimester can cause severe impairment of limb development, use of NSAIDS during the 1st trimester increases risk of miscarriage and malformation, use in 3rd trimester gestation increases the risk for premature closure of the ductus arteriosus.  Special Population Paediatric ❑ The metabolic profile between adults and children: maturational changes from fetus to infant to adolescent. ❑ Decreased clearance in the neonate and infant up to 2 months of age followed by a rise in metabolic capacity that could exceed that of an adult from ∼6 months to 2 years of age. ❑ Drugs that are primarily excreted renally are cleared at a faster rate than adults (children age of 2–12 years).  Special Population Paediatric ❑ Hepatic drug metabolism and elimination divided into two phases: oxidation, reduction, and hydrolysis (phase I) & hydroxylation and conjugation (phase II). ❑ e.g Phase I metabolism at birth is ∼30% that of adults and then rapidly increases to exceed adult rates by age 3 years for some drugs.  Special Population Paediatric ◻ Drastic changes in body form and proportion: Decreased total body water (TBW) and fat stores will affect absorption and volume of distribution of medication. ◻ Children less acidic stomach contents, delayed gastric emptying impacts the kinetics of absorption.  Special Population Geriatric ◻ Advances in medicine resulted in an increased life expectancy. ◻ Receive more drugs vs younger patients & poses a greater challenge to dose appropriately as geriatric patient potentially has altered kinetics due to declining organ function & concurrent disease and drug–drug interactions that are hard to predict.  Special Population Geriatric ◻ Older people with multiple disease requiring treatment with multiple medications may increase the risk for drug– drug interactions. e.g phenytoin and estrogens that are metabolized by the cytochrome P450 pathway. ◻ Decreased stomach acid, reduced intestinal blood flow & slower gastric-emptying time may affect the rate of drug absorption.  Special Population Geriatric ◻ Reduced lean body mass resulting in some medications distributing more easily. ◻ Reduced hepatic blood flow & mass can lead to a decrease in drug metabolism & increased concentrations of circulating medication. ◻ Renal function decline with age & decrease in filtration rate can result in the accumulation of some medications. THANK YOU!