Controlled Substances and Pregnancy Categories

NUR 320 Module 1B: Introductory Topics for Pharmacology

• This module covers introductory topics in pharmacology for nursing students
• The instructor is Mary Rose Gaughan, PhD, RN, CNE at D'Youville University.

Agenda

• Terminology and guidelines for drug order interpretation and transcription
• Legal and ethical implications related to drug administration
• Principles of drug action
• Developmental and cultural (ethnic) considerations

Today's Objectives

• Describe the concepts and principles of drug action
• Identify developmental and cultural considerations of pharmacology and drug administration
• Understand terminology and guidelines related to pharmacology

Pharmacology

• The study of biological effects of chemicals
• Drugs are chemicals introduced to the body to cause a change
• Herbals and non-pharmaceuticals can also cause changes to the body
• Pharmacotherapeutics uses drugs to prevent, diagnose, or treat disease processes
• Pharmacotherapy uses drugs to prevent, diagnose, or treat symptoms and disease processes

What does this mean to nursing practice?

• Nursing guidelines require safe practice when administering medications
• Drugs can have many effects - some helpful, some undesirable or harmful
• Responsibilities include: administration of drugs, assessing drug effects, intervening to make the drug regimen more tolerable, providing patient teaching, monitoring the overall care plan to prevent medication errors

Sources of Drugs

• Natural sources: plants, animals, inorganic compounds
• Synthetic sources: genetic engineering, improving established medications

Classification of Drugs

• Classified according to effects on a particular body system, therapeutic use, and chemical characteristics
• Drugs fit into many groups because of their effects on the human body
• Example: morphine – CNS depressant and an opioid analgesic

Prototype

• Often the first drug of the class to be developed
• The standard to which newer drugs are compared to
• Example: Morphine is the prototype analgesic
• Some groups lack a universally accepted prototype
• Some prototypes are replaced over time with newer, more commonly utilized drugs

Generic and Brand Names

• Generic: related to the chemical or official name, independent of manufacturer, presented in lowercase letters
• Brand Name: also known as trade name, designated and patented by the manufacturer, presented with a capital letter
• US Adopted Names Council assigns generic names
• Generic names are required to be therapeutically equivalent and less expensive than brand names
• Monitored by FDA

Drug Evaluation

• U.S. Food and Drug Administration (FDA) has tight control
• Regulates development and sale of drugs
• Ensures safety and reliability of drugs
• Several stages of development to determine if benefits outweigh the known and potential risks of the medication
• Pre-clinical trials, phase I, II, and III studies
• Orphan drugs – discovered but not financially viable, have not been 'adopted' by a drug company
• May be useful in treating rare diseases or have potentially dangerous adverse effects

FDA Trials and Studies

• Pre-clinical trials: do not use humans (use animals) to test drug potential, determine whether the drug has effects in living tissue, evaluates adverse effects
• Phase I studies: human volunteers to test safety and dosage; healthy volunteers with the condition the medication is designed to help; informed consent
• Phase II studies: more patients who have the disease the drug is intended to treat; performed across the country; if unacceptable adverse effects are detected, the drug is removed from testing
• Phase III studies: larger sample of population; determine treatment benefit and monitor side effects; participants keep journals and record symptoms
• FDA approval (Phase IV): continual evaluation after approval for marketing

FDA Labels and "Off-Label" Uses

• Prescribing information from studies is refined and "labelled".
• Label lists the approved uses, risks, and benefits of medication based on clinical trials
• "Off-label" uses of a drug are not part of the stated therapeutic indications the drug was approved for

Legal Regulation of Drugs

• FDA regulates development and sale of drugs
• Local laws further regulate distribution and administration of drugs
• Vary from state to state, and within a state
• Federal legislation affects clinical use of drugs

Safety in Pregnancy

• Category A: Adequate studies not demonstrated a risk to the fetus in any study
• Category B: Animal studies have not demonstrated a risk to the fetus, but there are no adequate studies in pregnant people
• Category C: Animal studies have shown an adverse effect on the fetus, but there are no adequate studies in humans
• Category D: Evidence of human fetal risk, but potential benefits may be acceptable
• Category X: Studies in animals or humans demonstrate fetal abnormalities or adverse reactions

Controlled Substances

• Schedule I: high abuse potential, no accepted medical use (heroin, LSD)
• Schedule II: high abuse potential, severe dependence liability (narcotics, amphetamines, barbiturates)
• Schedule III: less abuse potential than Schedule II, moderate dependence liability, certain narcotics
• Schedule IV: less abuse potential than Schedule III, limited dependence liability, sedatives, antianxiety agents
• Schedule V: limited abuse potential, small amounts of narcotics (codeine)

Sources of Drug Information

• Drug labels: name, dosage, expiration date, warnings
• Package inserts: by manufacturer, all chemical and study information, most accurate source
• Reference books: compilation of package inserts
• Journals: new drugs/classes, specific treatment protocols
• Internet information: government and association websites

Pharmacodynamics

• Study of interactions between chemical components of living systems and foreign chemicals (drugs)
• Drugs work in one of four ways:
  • Replacing missing chemicals
  • Increasing or stimulating cellular activities
  • Depressing or slowing cellular activities
  • Interfering with foreign cells (e.g., microorganisms or neoplasms)

Receptor Sites

• Specific areas on cell membranes that react with certain chemicals
• "Lock and key" analogy
• Key = specific chemical
• Lock = receptor site
• Interactions: Agonists, competitive antagonists and non-competitive antagonists

Drug-Enzyme Interactions

• Drugs can cause effects by interfering with enzyme systems
• Enzyme systems work in a cascade fashion, with one enzyme activating another one

Selective Toxicity

• Ability of a drug to attack only those systems found in foreign cells

Pharmacokinetics

• Study of how medications travel through the body
• Includes absorption, distribution, metabolism (biotransformation), excretion
• In clinical practice, nurses must consider: onset of drug action, drug half-life, timing of peak effect, duration of drug effects, site of excretion

Critical Concentration and Therapeutic Index

• Critical concentration: amount of drug needed for a therapeutic effect
• Therapeutic index: ratio of blood concentration where a drug becomes toxic to concentration where it is effective
• Loading dose: higher dose than usual to reach critical concentration sooner

Absorption

• Time from drug introduction until it reaches circulating fluids and tissues
• Sites of absorption, rate and amount absorbed (e.g., IV fastest, bypasses barriers, PO non-invasive)
• Influencing factors: chemical instability, injection methods, intestinal issues

Distribution

• Movement of drug into body tissues
• Factors: blood circulation, cell membrane permeability, plasma protein binding
• Bound drug = longer duration of action
• Unbound drug = quicker action, excretion

Biotransformation (Metabolism)

• Liver is the primary site
• Changes drugs into new chemicals
• First-pass effect: drugs taken by mouth can be significantly reduced by metabolism in the liver before reaching the circulatory system
• Factors for metabolism: site, route, prior condition

Biotransformation (Metabolism)

• Hepatic Enzyme System (CYP-450): abundant in the liver, metabolizes drugs
• Drugs can increase or decrease CYP-450 activity, affect metabolism of other drugs
• Liver disease and other factors affect drug metabolism

Excretion

• Kidneys play the most important role in excretion
• Drugs made water-soluble during metabolism readily excreted by the kidney, others secreted or reabsorbed
• Kidney dysfunction can lead to toxicity due to the inability to excrete the drug.

Pharmacokinetics Recap

• Description of drug movement through the body
• Drugs dissolved, lost in stomach/intestines, absorbed across intestinal wall
• Drug in liver, biotransformed → non-effective state (bound to plasma proteins), drug in circulation
• Broken down in tissues, reaching reactive tissues → excretion

Half-life

• Time when drug in the body reduces to half of its peak level
• Short half-life = more frequent dosing
• Liver/kidney dysfunction can lengthen half-life

Factors Influencing Drug Effects

• Interactions: when two or more drugs taken together can cause adverse effects
• Factors: weight, age, sex, physiological factors, pathological factors, genetic factors, immunological factors, psychological factors, environmental factors, drug tolerance, drug accumulation, interactions

Adverse Effects

• Primary actions: effects that are extensions of desired actions
• Secondary actions: effects not related to therapeutic effect
• Drugs cause effects in the body.
• Drug allergies/hypersensitivity can happen when patient develops antibodies.
• Adverse effects can include: dermatological reactions, GI irritation, superinfection, blood dyscrasia.

Drug-Induced Tissue & Organ Damage

• Adverse effects can include rashes, hives, Stevens-Johnson syndrome, stomatitis, GI irritation, nausea, vomiting, constipation, diarrhea, superinfections, and blood dyscrasia

Toxicity

• Hepatotoxicity: liver cell damage
• Nephrotoxicity: kidney damage
• Poisoning: overdose damaging multiple body systems

Alterations in Glucose Metabolism

• Hypoglycemia: low blood glucose
• Hyperglycemia: high blood glucose

Electrolyte Imbalances

• Hypokalemia: altered renal exchange system causing potassium loss (e.g., loop diuretics)
• Hyperkalemia: potassium retention and increased serum potassium (e.g., anti-neoplastic drugs)
• Other imbalances: hypercalcemia, hypocalcemia, hypernatremia, hyponatremia, hypermagnesemia, hypomagnesemia

Sensory Effects

• Ocular damage: drug deposits cause inflammation, leading to blindness
• Auditory damage: tiny vessels/nerves in auditory nerve easily irritated, may lead to ringing in ears

Neurological Effects

• General CNS effects: alterations in electrolyte and glucose levels, CNS stimulants/depression
• Anticholinergic effects: blockage of cholinergic receptors, many cold and anti-histamines cause these
• Extrapyramidal symptoms: dopamine levels affected, Parkinsonian symptoms, antipsychotic/neuroleptic drugs cause these
• Neuroleptic Malignant Syndrome: general anesthesia can cause this, high fever, potentially fatal

Teratogenicity

• Drugs that reach a developing fetus or embryo can cause death and congenital defects
• Defects include skeletal abnormalities, CNS alterations, heart defects

Nursing Process

• Assessment, nursing conclusions, planning, intervention, evaluation; obtaining medication history
• Application of the nursing process ensures safe, efficient, scientifically based quality, holistic care

Comfort Measures

• Managing adverse effects
• Lifestyle adjustment (e.g., alterations in activities, diet)
• Placebo effect (anticipation of drug's helpfulness)

Patient and Family Education

• Drug education needs to include: drug name, action, dose, timing, storage precautions, specific OTC drugs, special comfort measures, safety measures, and toxicity warning signs.
• Medication errors must be reported according to the policy of the healthcare facility.

Medication Errors

• Nurse's Role: right patient, right drug, right dose, right route, right time, right preparation, right recording, encouraging patient autonomy, provide health teaching.
• Patient's Role: keeping an accurate record, knowing what each drug is used for, reading labels, following directions, speaking up when necessary, using safe devices.

Reporting Medication Errors

• Errors must be reported at the national and institutional level
• Compiling reports to prevent recurrence
• Issuing HCP warnings
• Suggesting ways to avoid errors in the future

This quiz explores the classifications of controlled substances and their implications for drug usage during pregnancy. It covers topics such as the significance of different categories and schedules of drugs, focusing on abuse potential and safety for expectant mothers.