CH 13 Principles of Pharmacology

What is the defining element of paramedic clinical practice?

Medication administration

What can medications do for patients?

Correct or decrease the severity of an illness or injury, manage life-threatening conditions, and substantially reduce patient discomfort.

What severe consequences can occur from medication errors?

Administering the wrong medication, via the wrong route, incorrect dose, or failing to follow correct technique.

What is pharmacology?

The scientific study of how various substances interact with or alter the function of living organisms.

What historical sources have been used for medications?

Chemicals from plants and animals, used for centuries to cure diseases and treat symptoms.

What do evidence-based guidelines assist clinicians with?

Using pharmacologic interventions.

What is the purpose of the Pure Food and Drug Act of 1906?

To regulate medication labels and prevent altering of labels.

What does the FDA do?

It approves new medications and removes unsafe medications from use.

What is the Controlled Substances Act of 1970?

It classifies medications with potential for abuse into five categories (schedules).

What are primary sources of medication?

Plants, animals, minerals, microorganisms, synthetic, and semisynthetic sources.

What must medications have according to regulations?

Manufacturing lot number and expiration date.

What are the three types of medication names?

Chemical name, nonproprietary (generic) name, and brand (proprietary) name.

What is a medication monograph?

A medication profile that includes information such as dosing, route of administration, and contraindications.

What does the AHA classification indicate?

The strength of evidence supporting the use of a medication, ranging from Class I (strong evidence) to Class III (no benefit or harm).

What are the requirements for medication storage?

Provide adequate protection, convenient access, prevent physical damage, and control temperature.

What additional security measures are required for controlled substances?

Additional record keeping, disposal precautions, and strict regulations.

What is pharmacodynamics?

The alteration in body function or processes as medication is administered.

What does pharmacokinetics refer to?

The action of the body on a medication, including absorption, distribution, biotransformation, and elimination.

How do medications interact with receptor sites?

Medications bind with receptor sites of target cells, activating or preventing normal cell function.

What is the role of endogenous and exogenous chemicals in pharmacodynamics?

They activate receptor sites in proteins connected to cells.

What can cause toxic effects from medications?

Incorrect doses, incorrect route, malfunctions, or unique patient reactions.

What is the significance of 'tall man' lettering in medication names?

It helps to distinguish between similar-sounding medications to prevent errors.

What factors do paramedics consider when selecting medication reference sources?

Reliability, depth of information, accessibility, cost, availability of updates, and size of materials.

What are some common adverse reactions to medications?

Adverse reactions can vary widely and may include allergic reactions, side effects, or interactions with other medications.

What is the importance of medication testing and clinical trials?

To ensure the safety and efficacy of medications before they are approved for public use.

What is the purpose of protective bins in medication storage?

To facilitate quick and accurate identification and prevent physical damage.

What should be avoided in medication storage?

Direct sunlight, extreme temperatures, and physical damage.

What are the two types of medications that affect cellular activity?

Agonist medications and antagonist medications.

What is the primary function of agonist medications?

To bind with receptor sites and initiate or alter cell action.

What does 'affinity' refer to in the context of agonist medications?

The medication's ability to bind with receptor site(s).

What determines the number of bound receptor sites for agonist medications?

Concentration and affinity.

What is the 'threshold level' in pharmacodynamics?

The point at which the initiation of alteration of cellular activity begins.

What happens when all receptor sites become occupied?

The cell's maximum capacity is reached.

What is 'potency' in relation to agonist medications?

The concentration of medication required to initiate a cellular response.

What is 'efficacy' in pharmacodynamics?

The ability to initiate or alter cell activity in a therapeutic or desired manner.

What is the role of antagonist medications?

To bind with receptor sites and prevent cellular response to agonist chemicals.

What are competitive antagonists?

Antagonists that temporarily bind with cellular receptor sites and displace agonist chemicals.

What distinguishes noncompetitive antagonists from competitive antagonists?

Noncompetitive antagonists permanently bind with receptor sites and cannot be overcome by increased doses of agonist chemicals.

What are partial agonist chemicals?

Chemicals that bind to receptor sites and initiate less cellular activity than full agonists.

What are alternative mechanisms of drug action?

Medications that alter cell function without interacting with receptors.

How do antimicrobials function?

They target specific substances present in the cell walls of bacteria or fungi.

What is the function of chelating agents?

To bind with heavy metals and create a compound that can be eliminated from the body.

What is the role of diuretics?

To create osmotic changes that alter the distribution of fluids and electrolytes.

What factors affect weight-based dosing in medications?

Age, weight, environment, genetics, pregnancy, and psychosocial factors.

How does age affect weight-based dosing?

Water-soluble medications may require higher doses for infants than for adults, while fat-soluble medications may require higher doses in the elderly.

What is a limitation of weight-based dosing?

It requires the patient's weight in kilograms and does not consider alterations in distribution, metabolism, and elimination.

How can hyperthermia affect drug metabolism?

It may increase metabolism of drugs and reduce the amount of drug returned to circulation.

What precautions are needed regarding genetics in medication dosing?

Extra precautions are required for conditions like primary pulmonary hypertension and sickle cell disease.

What physiologic changes during pregnancy affect medication dosing?

Changes in absorption, distribution, and elimination of medications.

What should be considered when administering medications to pregnant women?

The effect of medication on the fetus and the need to consult FDA pregnancy risk categories.

What psychosocial factors can affect medication response?

Pain, anxiety, and discomfort can vary among individual patients.

What is the difference between a side effect and an adverse effect?

A side effect is a secondary effect of a medication, while an adverse effect is a harmful or undesired effect.

What is an adverse effect in medication?

An undesired clinical change that can be either desirable or harmful.

What are common adverse effects of medications?

Nausea, vomiting, sedation, respiratory depression, and dizziness.

What is the therapeutic index?

The relationship between the median effective dose (ED50) and the median lethal dose (LD50) of a medication.

What does a large therapeutic index indicate?

The medication is considered safe.

What is an immune-mediated medication response?

An allergic reaction that occurs in genetically predisposed patients after initial exposure to an allergen.

What is medication tolerance?

A decrease in medication efficacy when taken repeatedly, often due to down-regulation of receptors.

What is tachyphylaxis?

A rapid decrease in response to a drug after repeated doses.

What are the risks associated with medication interactions?

They can increase, decrease, or alter the effects of another medication.

What factors determine the pharmacokinetics of a medication?

Dose, route of administration, and clinical status of the patient.

What is bioavailability?

The percentage of unchanged medication that reaches systemic circulation.

What is the preferred method of medication administration in prehospital settings?

Intravenous (IV) administration.

What is the bioavailability of intravenous administration?

100%.

What is the primary concern with endotracheal administration?

It is not reliable and requires a higher dose than IV administration.

What is the advantage of intranasal administration?

Rapid absorption with bioavailability close to 100%.

What is the bioavailability of rectal administration?

Greater than 90%.

What is the main limitation of intramuscular (IM) administration?

The need to confirm the medication is appropriate for IM use and the technique for injection.

What is the purpose of dermal and transdermal administration?

To deliver a constant dose of medication over a long period.

What is the primary use of sublingual administration?

Often used for medications like Nitroglycerin, though it has low bioavailability.

What is a common risk associated with inhaled or nebulized medication administration?

Risk of bronchospasm and loss of a portion of the medication.

What is the role of osmosis in medication distribution?

It enhances the distribution of certain medications by allowing IV fluids to leave the intravascular space.

What is the process of filtration in medication distribution?

Redistribution of water and particles through hydrostatic pressure against semipermeable membranes.

What type of molecules pass easily through cell membranes?

Small nonionic and lipophilic molecules.

What are the three routes of entry for larger hydrophilic and ionic molecules?

Pinocytosis, facilitated diffusion, active transport.

What are the three barriers medications must cross to reach tissues?

Blood-brain barrier, blood-placenta barrier, blood-testes barrier.

In which organs does blood pass freely through capillaries?

Kidney, thyroid, pancreas, lungs, peritoneum.

What is plasma protein binding?

Medication molecules temporarily attach to proteins in blood plasma.

How can plasma protein levels affect medication concentration?

Concentration may change as plasma protein levels change or another medication is introduced.

What happens to lipophilic medications in obese individuals?

They are sequestered in fat tissues and released slowly, leading to prolonged effects.

What does the volume of distribution indicate?

The extent to which a medication will spread within the body.

What is the relationship between volume of distribution and plasma concentration?

Medications with lower volume of distribution have higher levels present in plasma.

What is biotransformation in medication metabolism?

The process by which a medication becomes a metabolite.

What are the types of metabolites produced during biotransformation?

Active metabolites and inactive metabolites.

Where does biotransformation primarily occur?

In the liver.

What is the role of the P-450 system in medication metabolism?

It alters the chemical structure of a medication, making it easier to eliminate.

What are the two patterns of medication elimination?

Zero-order elimination and first-order elimination.

What is the half-life of a medication?

The time needed for metabolism or elimination of 50% of the substance in plasma.

What factors can alter the half-life of a medication?

Disease states, changes in perfusion, medication interactions.

How is medication administered to maintain a constant level in the body?

At a dose and frequency equal to the body's rate of elimination.

What are some routes through which medications can be eliminated besides the kidneys?

Lungs, stool, saliva, breast milk, perspiration.

What are common causes of medication errors?

Decisions based on memory, often in stressful, life-threatening situations.

What is a recommended practice to reduce medication errors?

Perform verbal read-back of orders and label syringes.

What are sympathomimetic drugs?

Drugs that have alpha or beta sympathetic properties.

What are the two groups of agents classified under sympathomimetic drugs?

Beta-1 adrenergic agonists and beta-2 adrenergic agonists.

What do beta adrenergic blockers do?

They prevent beta agents from exerting their full effects.

What is the effect of Etomidate in airway management?

It is a profound sedative with minimal effect on blood pressure.

What is a key characteristic of Ketamine in airway management?

It causes profound dissociation and anesthesia while maintaining BP and heart rate.

What are the properties of benzodiazepines?

They have potent antiseizure, anxiolytic, and sedative properties.

What is the role of chemical paralytic agents in airway management?

They provide muscle relaxation and facilitate airway device placement.