PowerPoint 2 Flashcards
Core Drug Knowledge In Pediatrics
Effects of drug therapy are similar for children and adults.
The major difference is in the drug dosage.
Dosage is usually specified in milligrams of drug per kilogram of body weight (mg/kg).
It is now considered unethical to exclude children from drug studies.
Until all drugs have been tested and labeled for use in children, nurses need to be aware that off-label use will occur.
Pediatric Pharmacology
Dose calculations must be exact to size and age
They are very susceptible to many insults
Skin is thin and permeable
Stomach lacks acid to kill bacteria
Lungs lack mucous barriers
Body temperatures are poorly regulated
Liver and kidneys are immature
Compared with adults, infants and children have a greater body surface area and more permeable skin.
The infant’s gastrointestinal (GI) tract is less acidic and thus has a higher pH than that of an adult.
Pediatric Pharmacokinetics
Differences in body water and fat
Higher concentration of water; increased doses of water-
soluble drugs needed.
Lower concentration of fat; decreased doses of fat-soluble drugs needed.
Immature liver function
The neonate’s immature liver produces fewer plasma proteins unbound free drug.
Immature blood–brain barrier
At birth, the blood–brain barrier is not fully developed vulnerable to CNS toxicity.
Pharmacokinetics: Execution/Pediatrics
The neonate, especially the preterm infant, has immature kidneys, and renal excretion of drugs is slow.
A few drugs are excreted through the biliary tree into the intestinal tract.
Biliary blood flow is decreased during the first few days of life.
Pharmacokinetics: Pregnancy
Effects of progesterone…
GI absorption affected by:
Decreased gastric tone and motility
Prolonged stomach emptying time
Pulmonary absorption affected by:
Increased tidal volume
Pulmonary vasodilation
These increases enhance absorption of drugs that are inhaled.
Hemodynamic changes in the cardiovascular system alter drug distribution and metabolism. Blood volume doubles/HR increase
Drugs may compete with pregnancy hormones for albumin-binding sites.
Pharmacokinetics: Distribution & Metabolism/Pregnancy
Hemodynamic changes in the cardiovascular system alter drug distribution and metabolism. Blood volume doubles/HR increase
Drugs may compete with pregnancy hormones for albumin-binding sites.
Drug metabolism is not altered by pregnancy or breastfeeding.
Changes in renal plasma flow Glomerular filtration rates GFR increases by 50% Renal tubular reabsorption Drug excretion rates may be increased during pregnancy.
Pregnancy Contraindications and Precautions
Critical period of organogenesis- from implantation up to approximately days 58 to 60 after conception.
If drugs that cause teratogenic effects are administered during this period, major malformations of fetal organ systems may result.
FDA Categories
Cat. A: No risk to fetus in human studies
Cat. B: No human studies available to show risk
Cat. C: Animal studies +risk, no human studies available
Cat. D: + human risk, but consider benefits in life-threatening situations
Cat. X: +++ human risk outweighs benefits; contraindicated
Lifestyle, Diet and Habits
Alcohol is a known human teratogen.
Cocaine abuse is also known to cause adverse fetal effects and is suspected to be a human teratogen.
Opiate abuse does not appear to significantly increase the risk for congenital anomalies BUT associated with other adverse outcomes.
Tobacco smoke—fetal growth retardation.
Geriatric Pharmacology
Decreased acid levels in stomach, decreased motility, decreased blood flow
TBW is decreased, fat content is increased because of decreased lean body mass
Protein binding sites are reduced due to aging liver and reduced intake
Liver blood flow is reduced; drug metabolism is decreased
Excretion is affected as the kidneys blood flow is decreased and the number of intact nephrons are decreased
good patient AND FAMILY teaching!!
Substance Abuse
Tolerance occurs when the body develops a natural resistance to the drug’s physical or euphoric effects.
Physical dependence occurs when actual changes in body cells cause the body to “need” the drug for homeostasis.
Psychological dependence involves the compulsive use of a drug. It results from the direct influence of drugs on brain chemistry.
Factors Influencing Drug Abuse
Genetic factors: certain genes may predispose a person to, or protect the person from, drug abuse.
Developmental and environmental influences: can trigger changes in brain hormones, making a person more at risk.
Mood Disorders/Availability of Drugs
Risk traits: low tolerance for frustration, impulsivity, manipulativeness, fears of failure, feelings of inadequacy, resentment, hostility, and anger.
Central Nervous System Stimulants
Most commonly abused CNS stimulants - cocaine and the amphetamines.
Initial increase in HR and BP, energize muscles, decrease appetite, and cause some degree of mental and physical alertness.
All stimulant drugs pose a risk of both physical and psychological dependence.
As a general rule, intoxication with stimulant drugs is more dangerous than withdrawal.
Central Nervous System Depressants
CNS depressants decrease heart rate, respiration, muscular coordination and energy and cause constipation, depression, nausea, vomiting, physical dependence.
Commonly abused CNS depressants include sedative-hypnotics, alcohol, barbiturates, and benzodiazepines.
Alcoholism is the number one drug problem in America.
Abrupt withdrawal from long-term use of sedative-hypnotic drugs should never be attempted because withdrawal symptoms are serious and potentially fatal.
Opioids
Opioids are commonly prescribed to relieve pain, suppress coughing, enhance anesthetic effect for surgery, and relieve severe diarrhea.
These narcotic drugs have a high potential for abuse and are extremely addicting both physically and psychologically.
All opioids affect the CNS and cause cerebral changes, mood changes, confusion, euphoria, and analgesia.
Regular use of narcotics over several weeks usually results in tolerance to the drug’s effects.
Withdrawal effects: muscle pain, nausea and vomiting, abdominal cramps, and diarrhea.
Tranquilizers
Certain tranquilizing drugs, known as “date rape” drugs, have made headlines. They are Rohypnol and gamma- hydroxybutyrate (GHB).
Rohypnol is 10 times more potent than diazepam (Valium).
Rohypnol induces slowing of psychomotor performance, muscle relaxation, decreased blood pressure, sleepiness, and amnesia.
Some adverse effects: drowsiness, headaches, memory impairment, dizziness, nightmares, confusion, and tremors.
GHB is a powerful, rapidly acting CNS depressant.
Produced naturally by the body in small amounts, the physiologic function of GHB is unclear.
Hallucinogens
Hallucinogenic drugs have pronounced mental and emotional effects because they distort the way the brain interprets sensory information.
Included in this category are marijuana, mescaline, psilocybin, lysergic acid diethylamide [LSD], dimethyltryptamine [DMT], and phencyclidine hydrochloride [PCP]).
These drugs can be inhaled, injected, or swallowed.
They cause a long-lasting reduction in the brain’s supply of serotonin and produce powerful psychic changes.
Inhalants
The term “inhalants” refers to products that can be abused by inhaling them through the nose or mouth to achieve an intoxicating effect.
Because they are easily accessible, inexpensive, and easy to conceal, inhalants are some of the first substances abused.
Effects of inhalant use resemble alcohol inebriation.
The user initially experiences stimulation, a loss of inhibition, and a distorted perception of reality and spatial relations.
After a few minutes, the senses become depressed, and a sense of lethargy arises as the body attempts to stabilize blood flow to the brain.
Users also experience headaches, nausea, vomiting, slurred speech, loss of coordination, and wheezing.
Designer Drugs
These drugs are similar in chemical structure to existing drugs and are developed with relative ease in illegal laboratories.
They are extremely potent, and when used recreationally, they have addictive capabilities greater than those of existing drugs.
These drugs can destroys brain cells and much of voluntary muscular movement.
Anabolic androgenic steroids
Anabolic androgenic steroids are synthetic formulations of the male hormone testosterone.
The abuse of these drugs in men and women is widespread to increase strength and enhance athletic performance.
Anabolic androgenic steroids also have a dramatic effect on emotions and make the user feel more confident and aggressive.
Continued use of anabolic androgenic steroids may lead to emotional instability, rage, depression, or psychosis.
Serious health effects include sex hormone imbalances, changes in secondary sexual characteristics, permanent sterility, hepatic cancer, and myocardial infarction.
Alcohol
Pharmacokinetics
Completely absorbed within 2 hours
Immediately distributed
High concentrations in the brain, liver, lung, and kidney
Metabolism damages liver cells and poses risk of organ damage
Excreted by kidneys, breath, and sweat
Pharmacodynamics
Interferes with the transmission of nerve impulses
Sequentially depresses the CNS
Very narrow margin between anesthetic dose and lethal dose
Irritates the gastrointestinal (GI) tract Causes altered bowel function Creates fatty deposits in the liver Inhibits antidiuretic hormone Disrupts endocrine functions
Cocaine
Rapidly absorbed into the bloodstream
Rapidly metabolized in the liver and the blood
Characterized by tachyphylaxis
rapidly decreasing response to a drug following administration of the initial doses
Elimination half-life
50 min for oral route
80 min for intranasal route
60 min for IV route
Opiods
Absorption rate increases from oral use to IV injection
Effects within 30 minutes after oral
Effects within 5-15 minutes after smoking or IV
Effects persist for 4-6 hours
Converted to morphine and excreted by the kidneys
Marijuana
Dronabinol (Marinol)
Treats anorexia in AIDS patients
Reduces nausea and vomiting during chemotherapy
Possible reduction of intraocular pressure associated with glaucoma
Systemic availability of THC after smoking is about 25%.
Plasma concentration occurs after 10 to 30 minutes.
Duration of entire effect is 2-3 hours.
Decreased myocardial oxygen supply
Dose-related increase in heart rate
Impaired fertility
Repeated psychotic episodes and personality changes
Three kinds of world-view health beliefs
Biomedical health beliefs
Magicoreligious health beliefs
Holistic health beliefs
Four facets of the individual’s nature are:
Physical
Mental
Emotional
Spiritual
