Side Effects and Interactions Flashcards
Drug
Any substance that brings about a change in biologic function through its chemical actions
Pharmacodynamics
- How the drug effects the human or animal body
- Involves: receptor binding, post-receptor effects, chemical interactions
What physiological changes affect the pharmacodynamics of a drug?
Disorders (Genetic mutations, malnutrition, Parkinson’s disease), Aging, and other drugs present
What are the types of genetic mutations?
Deletion, duplication, inversion, insertion, translocation
Pharmacokinetics
- How the body affects the drug
- Determines the onset, duration, and intensity of the drug’s effect
What are the four factors of pharmacokinetics?
ADME: Absorption Distribution Biotransformation Excretion
What is absorption?
- A factor of pharmacokinetics
- How the body “takes in” the drug
- Determined by the drug’s physiochemical properties, formulation and route of administration
What is distribution?
- A factor of pharmacokinetics
- How the drug is distributed to the body tissues
- Usually uneven
- Distribution is slow to lipids and muscles
What is biotransformation?
- A factor of pharmacokinetics
- What the body does to the drug
What is excretion?
- A factor of pharmacokinetics
- The process of elimination of the drug
- Through the kidneys if hydrophilic
- Other routes include: GI tract, lungs, saliva, sweat, breast milk
What are the routes of administration?
Oral, intramuscular, subcutaneous, inhalant, intravenously
What is binding?
How the chemical “sticks” to proteins
What is a “free” drug?
- Unbound; the amount of drug in the body available to be bound
- Can diffuse to tissue sights where the drug effects occur
- The amount of this is what causes side effects
- The more free drug, the more effect you can have if you have the proteins and enzymes that will bind
What is albumin?
- A protein manufactured in the liver
- Helps balance the amount of blood flowing through the arteries and veins and moves calcium, progesterone, bilirubin, and medications through a person’s blood
- Stops fluid in the blood from leaking into the tissues
- Critical plasma protein for mental health drugs
- Acidic drugs bind to albumin
- Normal: 3.4-5.4 g/dL (grams per deciliter)
- Low levels - liver disease
- High levels - dehydration
What is biotransformation?
- The process by which any substance that enters the body is changed
- Metabolizing the chemical
- Occurs in the liver, primarily (Caused by enzymes; Produces by-products: metabolites)
- Helpful to reduce symptoms
- Facilitates elimination from the body
Toxicity
Can occur when biotransformation is not working correctly
What is bilirubin?
- Orange-yellow pigment
- Needs albumin!
- Occurs in red blood cells when broken down by the liver
- Impacts health
- High levels - red blood cells are breaking down or waste is not clearing from blood
What is bilirubin implicated in?
Jaundice, anemia, cirrhosis of the liver, gallstones, hepatitis, Sickle cell disease (red blood cells destroyed too fast)
What is half-life?
- How long the drug stays in the body
- “the amount of time required for the serum concentration to be reduced by 50%”
- Used to determine dosage amount and intervals
What is steady-state?
-When drug concentrations in the blood reach a plateau so the amount administered is equal to the amount being eliminated
Why side effects?
- Symptoms occur because of chemical reaction
- Medications effect the chemicals all over the body
- Thus we have side effects
What are the mechanisms of side effects?
- Many molecules bind to more than 1 receptor
- A molecule can bind to receptors in more than 1 system
- There are many classes of receptors and molecules can interact with more than one
What are common anticholinergic side effects?
Dry mouth, urinary retention, blurred vision, headaches
What are common akathesia side effects?
Restlessness
What are more serious dystonic reactions?
- Painful muscle spasms (young men most at risk)
- Larnygospasms (can’t breathe)
What is Tardive Dyskinesia?
- Tremors, tongue thrusting, facial movements
- Occurs more with typical antipsychotics
- Indicates must stop drug immediately
What is agranulocytosis?
- Symptoms include fever, easy bruising, mouth sores, flu-like symptoms
- Decrease in white blood cells
- Must stop medication immediately
- Clozaril has the highest risk
Adrenaline/Epinephrine
- Fight or flight neurotransmitter
- Increases heart rate and blood flow
- Causes physical boost and heightened awareness
Dopamine
- Pleasure neurotransmitter
- Also causes feelings of addiction, movement, and motivation
- People repeat behaviors that lead to dopamine release
Noradrenaline/Norepinephrine
- Concentration neurotransmitter
- Affects attention and responding actions in the brain
- Involved in fight or flight
- Contracts blood vessels, increasing blood flow
- Sympathomimetic
- Increases heart rate, blood pressure, sweating, tremors, jitteriness, and anxiety
Serotonin
- Mood neurotransmitter
- Contributes to well-being and happiness
- Helps sleep cycle and digestive system regulation
- Affected by exercise and light exposure
GABA
- Calming neurotransmitter
- Calms firing nerves in CNS
- Inhibitory
- High levels improve focus
- Low levels cause anxiety
- Also contributes to motor control and vision
Acetylcholine
- Learning neurotransmitter
- Involved in thought, learning and memory
- Activates muscle action in the body
- Associated with attention and awakening
Glutamate
- Memory neurotransmitter
- Most common brain neurotransmitter
- Excitatory
- Involved in learning and memory
- Regulates development and creation of nerve contacts
Endorphins
- Euphoria neurotransmitters
- Released during exercise, excitement, and sex
- Reduces pain
