dosing considerations for vulnerable populations
DESCRIPTION
Dosing Considerations for Vulnerable Populations. Vulnerable Populations. Are groups of patients with a high risk for adverse drug effects Require careful dosing and/or medication selection. At-Risk Groups Include. Men and women of reproductive age Pregnant or breastfeeding women - PowerPoint PPT PresentationTRANSCRIPT
Copyright © 2015 F.A. Davis Company
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Dosing Considerations for Dosing Considerations for Vulnerable PopulationsVulnerable Populations
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Vulnerable PopulationsVulnerable Populations
Are groups of patients with a high risk for
adverse drug effects
Require careful dosing and/or medication selection
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
At-Risk Groups IncludeAt-Risk Groups Include
Men and women of reproductive age
Pregnant or breastfeeding women
Children and infants
Elderly patients
People with renal or hepatic disease
Obese or underweight patients
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Reproductive AgeReproductive Age
In women: Drugs can affect fertility or damage ova
In men: Drugs can alter sperm quality and quantity
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Pregnancy Safety CategoriesPregnancy Safety CategoriesA, B, C, D, XA, B, C, D, X
A: Studies have not shown a risk to the fetus B: Studies have not shown a risk to an animal
fetus; however, there are no well-controlled studies in humans
C: Animal studies show an adverse effect and there are no adequate studies in pregnant women or no animal studies have been conducted and there are no adequate studies in pregnant women Many drugs fall in category C
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Pregnancy Safety Categories (cont’d)Pregnancy Safety Categories (cont’d)
D: Studies in pregnant women have shown a risk to the fetus; benefits may outweigh potential risks
X: Studies in animals and pregnant women have shown evidence of fetal abnormalities; the drug is contraindicated in women who are or may become pregnant
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Drug Properties Impacting Drug Transfer Drug Properties Impacting Drug Transfer to Fetusto Fetus
Dosage Drug chemistry Lipid solubility Protein binding
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Pregnant WomenPregnant Women
First trimesterFirst trimester
A woman is least likely to know she is pregnant
Exposure of fetus to drugs is most harmful during the first trimester
Teratogenic drugs may lead to fetal malformation or miscarriage
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Pregnant Women (cont’d)Pregnant Women (cont’d)
Third trimesterThird trimester Drugs may not be safely metabolized and
excreted by the fetus
After deliveryAfter delivery Infants no longer have the placenta to help with
drug excretion, and drugs given before delivery may cause toxicity
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Pregnant Women (cont’d)Pregnant Women (cont’d)
For pregnant women who require medication, both mother and fetus must be considered
Weigh risks and benefits
Rule of thumb:
LOWEST EFFECTIVE DOSE
for the
SHORTEST PERIOD OF TIME
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
LactationLactation
Many drugs are known or thought to be excreted in breast milk
Dose in breast milk will be low, but still may cause adverse effects in the infant
Some drugs interfere with milk supply
American Academy of Pediatrics (AAP) lists drugs usually compatible with breastfeeding: http://pediatrics.aappublications.org
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Lactation (cont’d)Lactation (cont’d)
AAP encourages breastfeeding if drug is unlikely to cause harm
In poorer nations, bottle feeding may not be an alternative
Research medication at LactMed: http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Pediatric ClassificationsPediatric Classifications
Premature Infant: <38 week gestation
Neonate/newborn: Younger than 1 month
Infant: 1 month up to 1 year
Child: 1 year up to 12 years
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Pediatrics: Pediatrics: Neonates and PreemiesNeonates and Preemies
Difficulty in dosing is secondary to
Immature function of body systems
Rapid weight changes
Progressive maturation of hepatic and renal function
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Pediatric DosingPediatric Dosing
Doses for children are not automatically less than those for adults
Higher metabolic rate in children causes drugs to be processed more quickly
Higher doses are needed to maintain therapeutic blood levels
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Pediatric Dosing (cont’d)Pediatric Dosing (cont’d)
Medication doses are based on body weight or body surface area (BSA)
Body weight doses expressed as mg/kgmg/kg
BSA doses expressed as mg/mmg/m22
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
GeriatricsGeriatrics Physiological changes of people 65 and older affect the
action of many drugs
Beers criteria: Drug classes found to increase the risk of adverse effects in older adults. See Davis’ Drug Guide under Medication Safety Tools
Age-related changes affect pharmacokinetics
Absorption: Gastric pH less acidic, gastric emptying slowed, peristalsis slowed, reduction of blood flow in the GI tract
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Geriatrics (cont’d)Geriatrics (cont’d) Distribution: Decrease in lean body mass, increase in fat
content, reduction in total body water content, protein-binding sites are reduced caused by aging liver
Metabolism: Aging liver, decrease in liver blood flow causes a decrease in liver metabolism
Excretion: Decreased renal filtration rate due to reduction in blood flow, decrease in amount of nephrons
Aging changes lead to greater incidence of toxicity
Prescribe lowest possible dose at initiation of drug(s)
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Geriatrics (cont’d)Geriatrics (cont’d)Monitor for
Signs and symptoms of toxicity and side effects
Drug interactions
Usage and complications of OTCs and herbal drugs
Effectiveness
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Patients With Renal DiseasePatients With Renal Disease
Kidneys are the major organ of drug elimination
Failure to account for decreased renal function is a preventable source of adverse drug reactions
Assess Creatinine clearance
BUN and creatinine
Medication blood levels
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Patients With Liver DiseasePatients With Liver Disease
The liver is the major organ of metabolism
The liver changes drugs from fat soluble to water soluble so that kidneys can excrete them
Liver damage leads to higher levels of active drug and more toxicity
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Patients With Liver Disease (cont’d)Patients With Liver Disease (cont’d)
Monitor Liver enzymes Albumin, total protein
Assess patient for Enlarged liver Ascites, jaundice
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Obese patients Drug dosing often based on body weight
Some drugs do not penetrate fatty tissues
To prevent toxicity when giving drugs that do not penetrate fatty tissue (e.g., digoxin), determine dose by ideal body weight or estimated lean body mass
Patients With Extremes of Body SizePatients With Extremes of Body Size
Davis’s Drug Guide for Nurses,14th EditionDavis’s Drug Guide for Nurses,14th Edition
Copyright © 2015 F.A. Davis Company
Underweight patients likely to be Chronic alcoholics Patients with AIDS
Patients terminally ill with cancer and other debilitating illnesses
Patients with amputations
No standard formula for calculating dose in underweight patients; watch for toxicity
Patients With Extremes of Body Size (cont’d)Patients With Extremes of Body Size (cont’d)