3. Drug levels Time course of drug response Plasma drug levels Half life Plateau Reducing fluctuations
4. Pharmacology Drug tolerance Unusually low physiologic activity in response to a drug Person requires increased doses to get therapeutic effect
5. Pharmacology Cumulative effect Increasing response to repeated doses Occurs when rate of administration exceeds rate of metabolism Drug builds up; toxicity occurs
6. Pharmacology Idiosyncratic effect Under or over response Unexpected, unpredictable, unexplainable Drug interaction Occurs before, during, after administration of another drug Can be synergistic or potentiating or can be inhibiting
7. Side effect – unintended effect Adverse effect- unexpected and can be severe Drug toxicity- buildup of drug in blood Drug allergy- occurs after administration and can be anaphylactic SOB, tachy, hypotension, stridor Emergency
8. Neonatal and Pediatric Considerations: Pharmacokinetics Absorption Gastric pH less acidic Gastric emptying is slowed Intramuscular absorption faster and irregular
9. Neonatal and Pediatric Considerations: Pharmacokinetics (cont’d) Distribution The younger the person, the greater the % of total body water Greater TBW means fat content is lower Decreased level of protein binding Immature blood-brain barrier—more drugs enter the brain
10. Neonatal and Pediatric Considerations: Pharmacokinetics (cont’d) Metabolism Liver immature, does not produce enough microsomal enzymes Older children may have increased metabolism, requiring higher doses than infants Other factors
11. Neonatal and Pediatric Considerations: Pharmacokinetics (cont’d) Excretion Kidney immaturity affects glomerular filtration rate and tubular secretion Decreased perfusion rate of the kidneys may reduce excretion of drugs
12. Factors Affecting Pediatric Drug Dosages Skin is thin and permeable Stomach lacks acid to kill bacteria Lungs have weaker mucus barriers Body temperatures less well regulated and dehydration occurs easily Liver and kidneys are immature, impairing drug metabolism and excretion
13. Methods of Dosage Calculation for Pediatric Patients Body surface area method Using the West nomogram Body weight dosage calculations Using mg/kg
14. The Elderly Elderly: older than age 65 Healthy People 2010: older than age 55 Use of OTC medications Increased incidence of chronic illnesses Polypharmacy
15. Physiologic Changes in the Elderly Patient Cardiovascular Gastrointestinal Hepatic Renal
16. The Elderly: Pharmacokinetics Absorption Gastric pH less acidic Slowed gastric emptying Movement through GI tract slower Reduced blood flow to the GI tract Reduced absorptive surface area due to flattened intestinal villi
17. The Elderly: Pharmacokinetics (cont’d) Distribution TBW percentages lower Fat content increased Decreased production of proteins by the liver, resulting in decreased protein binding of drugs (and increased circulation of free drugs)
18. The Elderly: Pharmacokinetics (cont’d) Metabolism Aging liver produces fewer microsomal enzymes, affecting drug metabolism Reduced blood flow to the liver
19. The Elderly: Pharmacokinetics (cont’d) Excretion Decreased glomerular filtration rate Decreased number of intact nephrons
20. The Elderly:Problematic Medications Analgesics, including NSAIDs Anticoagulants Anticholinergics Antidepressants Antihypertensives Cardiac glycosides (digoxin) Sedatives and hypnotics Thiazide diuretics
22. Developmental considerations: Children Don’t say candy Use liquid Don’t lie about injections Older adults Altered memory Renal function, liver function Decreased absorption in GI tract Altered quality of organ response to drug
What is pharmacogenomics? Pharmacogenomics is the study of how an individual's genetic inheritance affects the body's response to drugs. The term comes from the words pharmacology and genomics and is thus the intersection of pharmaceuticals and genetics. Pharmacogenomics holds the promise that drugs might one day be tailor-made for individuals and adapted to each person's own genetic makeup. Environment, diet, age, lifestyle, and state of health all can influence a person's response to medicines, but understanding an individual's genetic makeup is thought to be the key to creating personalized drugs with greater efficacy and safety. Pharmacogenomics combines traditional pharmaceutical sciences such as biochemistry with annotated knowledge of genes, proteins, and single nucleotide polymorphisms
What is polypharmacy?Polypharmacy means "many drugs" and refers to problems that can occur when a patient is taking more medications than are actually needed. It is a particular concern for older adults, who make up 13% of the population but account for almost 30% of all prescribed drugs. The typical older adult takes one or more prescription drugs plus several OTC remedies, such as antacids, laxatives or pain-killers, often used without informing their physician. Some people have no problems at all, but others suffer because of the combination of drugs they take. Indeed, research has found that higher rates of depression and lower quality of life were results of a person's perception that they were taking too many drugsMrs. P., age 89, has appointments this week with her primary physician, a specialist for rheumatoid arthritis, an ophthalmologist, and a pulmonary specialist. What can be done to prevent possible polypharmacy with Mrs. P.?