Pharmacology
the study of medications and their actions, including drug origins, properties, and uses.
Drug
defined as a substance used for the diagnosis, treatment, cure, mitigation, or prevention (prophylaxis) of disease or a condition.
FDA have approved and standardized for safety, dosage accuracy, and effectiveness after undergoing several phases of formal independent testing.
Drug Sources (Plants)
Examples: Morphine sulfate, digitalis
At one time the majority of drugs originated from this and a number of medications based with this are still in use today.
Drug Sources (Animals)
Examples: heparin sodium thrombin
Nonsynthetic hormones are derived from this source including human sources; drugs obtained from cows are referred to as bovine and those from pigs as porcine
Drug Sources (minerals)
examples: calcium iron magnesium zinc
Derived from the earth, minerals, and mineral salts
Drug Sources (Laboratory Synthesis)
Examples: meperidine, sulfate (Demerol), aminoglycoside antibiotics
The majority of drugs used today are manufactured in the laboratory; laboratory synthesis is accomplished by two methods:
Synthetic drugs
manufactured totally from laboratory chemicals
Semi-synthetic drugs
natural substances that are chemically altered
Biotechnology
Examples: Hepatitis B vaccine
The newest source of drugs from the laboratory; results from a process known as genetic engineering or recombinant DNA technology
Pharmacodynamics
The interaction of drug molecules with target cells, resulting in biochemical and physiological actions. Types of drug interactions include inhibition or destruction of foreign organisms or malignant cells; protection of cells from foreign agents; supplementation or replacement of specific hormones, vitamins, or enzymes; and increasing or decreasing the speed of a physiologic function.
pharmacokinetics
The study of the movement of drugs through the body, involving absorption, distribution, biotransformation, and excretion is the term used to describe the metabolic processing of a drug within the body.
agonistic interaction
occurs when a drug potentiates or enhances the effect of another substance. The agonistic medication binds to a specific receptor site in the body, producing an alteration in biological function.
Synergistic Agents
act in combination to produce a stronger or more powerful effect than would be demonstrated if each agent was administered individually. the action of one agent increases the action of the other agent when delivered together. The use of midazolam (a sedativesedative Agent that produces a soothing or quieting effect but does not cause the person to sleep ) and fentanyl (a narcotic analgesic) permits the use of lower concentrations of volatile gases during the administration of general inhalation anesthesiaanesthesia Absence of sensation .
Additive Agents
alter some aspect of the action of the original agent. An example is the addition of epinephrine to the local anesthetic lidocaine to prolong the anesthetic action.
Antagonists
binds to the agonist’s receptor site, preventing agonist Refers to an agent that stimulates or prolongs the response of a drug or a physiologic action from binding there and causing its desired effect. This results in an absence of the agonist’s action, referred to as agonist reversal. This interaction is demonstrated when flumazinil (Mazicon®) is given to reverse the sedative effects of midazolam HCl (Versed®).
therapeutic action
a medication describes the application or situation for which the medication is used and the timing of the effects commonly associated with a given medication and dosage.
Indication
A reason to perform a specific procedure or prescribe a certain drug
is a listing of the medical conditions that the medication is known to treat. The dosage as well as the delivery form, may vary according to the patient’s medical condition, weight, and age.
Contraindications
A reason why a specific procedure or drug may be undesirable or improper in a particular situation
are a list of circumstances or medical conditions under which the medication should not be used. Depending on the medication and how it is metabolized in the body, common include pregnancy, liver failure, or renal failure.
Onset
is the period of time required for the effects of the medication to begin to be demonstrated in the patient.
Peak Effect
is the period of time when the maximum effect(s) of the medication are demonstrated in the patient.
Duration
is the overall period of time when the effects of a medication are demonstrated in the patient
Therapeutic effect
The concentration or dose of a medication used to produce the desired result without producing harmful effects
Side effect
An expected, undesirable, but tolerable effect of a medication. These can include symptoms such as dry mouth, constipation, diarrhea, dizziness or drowsiness.
Adverse effect
An undesirable and potentially harmful effect of a medication that can lead to organ damage or failure. Susceptible organs include the brain, liver, kidney, and cardiovascular system
A common reaction is hypersensitivity or allergic reaction, which can range from mild skin irritation to anaphylaxis
Toxic effect
An undesirable and unacceptable effect of a medication. The effect can include the promotion of growth of cancerous tumors (carcinogens) or the development of birth defects (teratogens).
Tolerance
A reduction in the effect of a medication given at the same dose over a period of time. The dosage of the medication must be increased in order to achieve the desired effect.
Addiction
A physical or psychological dependency on the effect of a medication.
Absorption
occurs at the site of administration, where the substance is eventually taken into the bloodstream by the capillaries. This process is referred to as passive transport
Passive Transport
requires no energy. Most drugs are transported in this manner.
Distribution
involves the transport of a medication within the body once it enters the circulatory system. Medication is distributed to the target cells for action, to the liver for biotransformation, and to the liver or kidneys for elimination.
Drug Administration Routes (Enteral)
Oral: Placed in the mouth and swallowed
Rectal: Placed in the rectum
Drug Administration Routes (Parenteral)
Intradermal: Placed b/w layers of skin
Subcutaneous (SC OR SQ): Placed in adipose tissue
Intramuscular (IM): Placed within the muscle
Intravenous (IV): Placed in vein
Intra-articular: Place in joint
Intrathecal: Subarachnoid space
Intracardiac: In the heart
Drug Administration Routes (Topical)
Buccal: Placed b/w the cheeks and teeth/gums until it dissolves
Sublingual: under the tongue
Instillation: hollow cavity such as conjuctivl fold or bladder
Inhalation: respiratory tract usually gas or aresol
Biotransformation
metabolism of a drug most often occurs in the liver, but other tissues, including the intestinal mucosa, lungs, kidneys, and blood plasma, may be involved. Several medications are converted to an active substance by the liver, but the main function of the liver in drug metabolism is to break down the drug molecules in preparation for excretion
Excretion
The effect of medication in the body continues until it is biotransformed The kidneys are primarily responsible for the filtration of medications from the blood and elimination of medications and metabolites as part of urine formation
Routes of Administration
is the method used to deliver the medication into the body. The most common routes of administration for medications in the operating room (OR) are parenteral with intravenous (IV) administration being the most common.
Drug Standards
Medications for use in the United States are required to undergo review and approval by the FDA
Drug Forms (Gas)
Oxygen and nitrous oxide are included in this category
Drug Forms (Liquid)
Two primary types of liquid preparations: solution and suspension
Drug Forms (Solution)
Drug (Solute) is dissolved in a liquid (solution)
Drug Forms (Aqueous)
Solution prepared with Water
Drug Forms (Syrup)
Sweetened aqueous solution
Drug Forms (Tincture)
Solution prepared with alcohol
Drug Forms (Elixir)
Sweetened alcohol solution
Drug Forms (Suspension)
Solid particles are suspended in a liquid—particles may settle and must be redistributed by shaking prior to administration of a suspension
Drug Forms ( Emulsion)
Combination of two liquids that cannot mix—droplets of one liquid are dispersed (suspended) throughout the other
Drug Forms (Solid)
Powder is considered a solid form of a drug—it may be in the powdered state, contained within a capsule, or compressed into tablet form—some powders must have liquid added (called reconstitution) prior to use—troches or lozenges also fall into this category
Drug Forms (Semisolid)
Creams, foams, gels, lotions, ointments, and suppositories
Two legal drug classifications most commonly used
prescribed medications and over-the-counter medications.
Controlled Substance
are those drugs with a high potential to cause psychological and/or physical dependence and abuse
The Controlled Substances Act of 1970
designates certain drugs as controlled substances, classifying these substances according to their level of addictiveness and therapeutic potential. The classification ranges from Class I, with a high potential for abuse and low therapeutic indication, to Class V, with a low potential for abuse and known positive therapeutic applications.
Class 1
Includes substances for which there is a high abuse potential and no current approved medical useheroin, marijuana, LSD, other hallucinogens, and certain opiates and opium derivatives
Class 5
Drugs in this category consist mainly of preparations containing limited amounts of certain narcotic drugs for use to treat coughing and diarrhea. (Federal law provides that limited quantities of these drugs may be bought without a prescription by an individual at least 18 years of age. The product must be purchased from a pharmacist, who must keep appropriate records; however, state laws vary, and in many states, such products require a prescription.)cough syrups with codeine; diphenoxylate (Lomotil)
Perscribed Medications
are those medications that, if used inappropriately, could cause significant harm to the patient. is a written order for the preparation and dispensing of a medication. includes the name, dose, quantity, and timing of a medication.
Over the counter medications
are pharmacologic agents that are prepared in a dosage that are safe to administer without the direction of a physician. Some prescription medications can be sold OTC in lower doses. Examples include ibuprofen (Motrin, Advil); 200-mg tablets are sold OTC, but ibuprophen (Motrin) 800-mg tablets require a prescription.
Alternative Medications
is becoming more predominant in today’s society. Dietary supplements include nutritional supplements, herbal medicines (also known as botanicals), probiotics, vitamins, minerals, and other natural products.
Fish oil/omega 3./DHA and Flaxseed oil are the most common
Medication Information (Trade Name)
the name assigned to a medication and copyrighted by the manufacturer for marketing (proprietary) purposes; may include a reference to the intended use.
Medication Information (Generic Name)
the nonproprietary name for a drug. It is often a shortened version of the chemical name. is often selected by the original developer and is written using all lowercase letters. may be produced by several manufacturers. is prominently displayed on the medication label.
Medication Information (Chemical Name)
the precise chemical composition and molecular structure of the medication. The chemical name is complex and difficult to use. is not included on the medication label, but is included in the package insert that accompanies the medication from the manufacturer
What does the Joint Commission publish
a “Look-alike/sound-alike” list of medications. Care should be taken to verify the generic name of the medication to reduce the potential for medication errors
Marcaine®
Generic Name: bupivicaine Chemical Name:2-piperidinecarboxamide,
Generic Name: hydrochloride Chemical name: 1-butyl-N-(2,6-dimethylphenyl), monohydrochloride,
Sensorcaine®
Chemical Name: monohydrate
Classifications
Drugs are classified in many ways for a variety of reasons; each classification may have several subclassifications. This can be confusing, as some of the classifications overlap and a specific drug may be cross-referenced in several categories.
How are drugs classified
according to their principal action, e.g., barbiturate; the organ or body system affected, e.g., neurologic agent; the physiological action produced by the drug, e.g., central nervous system depressant; or its therapeutic action, e.g., anticonvulsant. Phenobarbital is an example of a medication that fits into each of these categories.
Actions
define the effects of the substance at the target site
The theory of drug–receptor interaction
states that the active substance in the drug has an affinity for a specific chemical constituent of a cell. The interaction occurs on a molecular level with a specific receptor on the cell surface or within the cell to produce the pharmacological response.
The theory of drug–enzyme interaction
that a drug may combine with a specific enzyme to inhibit the action of the enzyme or alter the cellular response to the enzyme
nonspecific drug interaction
is related to a drug that does not act by either of the two previously described methods and is considered nonspecific in its interaction.
indication
is a listing of common medical conditions that a particular medication is used to treat.
Dosage
is the amount of medication delivered to the patient in order to achieve the desired therapeutic effect. will depend on several factors, including the patient’s age, weight, and overall medical condition
Concentration
is the ratio of solute to solvent, the two components of a solution. is found on the medication label and should be checked carefully for accuracy. can also come in a concentrated liquid form that may be used in the concentrated form or diluted for use in a less concentrated form. An example of this is heparin sodium. Heparin sodium is available in several concentrations, including 500 units per milliliter, 1,000 units per milliliter, and 10,000 units per milliliter. Normal saline for injection can be added to any of these heparin concentrations to make a dilute concentration.
Dose
is the overall amount of medication delivered to the patient....is documented in the patient’s record as part of the “sixth right” of medication administration. Cumulative does of medication should be documented
Application
is the medication’s use in the surgical setting. Consideration should also be given to any contraindications for use, such as patient sensitivity/allergy, seen with penicillin use in the penicillin-sensitive patient, or when administering vasopressin to a patient who is hypertensive, which could lead to a hypertensive crisis.
Some examples of different uses for medications
Lidocaine HCl is commonly used as a local anesthetic; however, lidocaine HCl can also be used as an antiarrhythmic to decrease abnormal heartbeats. The surgical technologist should be aware of how and under which situation each medication on the sterile field is used and delivered. Epinephrine, in concentrations of less than 1:100,000, can be injected as a vasoconstrictor, but in concentrations of 1:1,000, it should only be used topically to prevent serious patient complications, including death.
Calculation of Concentration
you need to convert the solution into units of medications per one unit of fluid; in other words, solute to solvent. This is accomplished using the following formula:
A : B = C : D
Percentages
represents a fraction in which the denominator is always 100, but percentages are typically expressed as a whole number followed by the percent symbol, %.
Conversion of Temapture
The conversion formulas for converting between Fahrenheit and Celsius scales are as follows:
(°F − 32) 5/9 = °C
(°C × 9/5) + 32 = °F
Units of Measure (Metric System)
also referred to as the International System of Units, is based on powers or multiples of 10 and the value of numbers is established by the use and placement of a decimal point to indicate whole numbers versus fractions.
Measurement of Metric system is based on
- Length: meter (m)
- Weight: gram (g)
- Volume: liter (l)
Abbreviations used in the metric system
- Length
- Meter = m
- Centimeter = cm
- Millimeter = mm
- Weight
- Kilogram = Kg or kg
- Gram = g
- Milligram = mg
- Microgram = mcg
- Volume
- Kiloliter = kl
- Liter = l
- Cubic centimeter = cc
- Milliliter = mL or ml
Apothecary system
based on the weight of a grain of wheat. In this system, 12 ounces (rather than the more commonly known 16 ounces) equals one pound. The units of measure are the minim for volume and the grain for weight.
Abbreviations used in the apothecary system
- Volume
- Minim = m
- Dram = dr
- Drop = gtt
- Ounce = oz
- Pint = pt
- Weight
- Grain = gr
- Pound = lb
Six Rights of medication administration
- The “right” patient
- The “right” drug
- The “right” dose
- The “right” route of administration
- The “right” time and frequency
- The “right” documentation, including labeling
Where are the six rights usually found
components of the physician’s medication order, whether written or verbal. In the OR, the list of medications commonly used for a specific procedure is found on the surgeon’s preference card
Ampule
Glass container that requires the top to be broken off to access the contents—usually contains liquid medication. Extra caution must be used when handling glass ampules to ensure that glass does not contaminate the medication upon opening
Vial
Plastic or glass container that has a rubber stopper at the top that is held in place with a metal retaining ring—may contain liquid, powder, or compressed powder
Preloaded Syringe
Usually contains liquid medication
Tube
Metal or plastic—may contain medication in cream, gel, or ointment forms.
What must the medication packaging for all drugs be labeled with?
- Drug name (trade and generic)
- Manufacturer
- Strength
- Amount
- Expiration date
- Route of administration
- Lot number
- Handling/storage precautions and warnings
- Instructions for reconstitution (if applicable)
- Controlled substances classification (if applicable)
What must be verified a minimum of 3 times before use?
medication name, strength, amount, and expiration date
Step one of the steps made by the circulator, surgeon and surgical tech during the transfer of medications
The circulator and surgical technologist check all medications and supplies prior to the start of the case (first identification/verification).
Step two of the steps made by the circulator, surgeon and surgical tech during the transfer of medications
The surgical technologist or circulator may initiate the request to transfer a medication to the sterile field.
Step three of the steps made by the circulator, surgeon and surgical tech during the transfer of medications
The circulator approaches the sterile field with the medication
Step four of the steps made by the circulator, surgeon and surgical tech during the transfer of medications
The circulator will hold the medication container so that both individuals can see the label. The circulator will read out loud the the name of the drug, strength of the drug, and expiration date (second identification/verification).
Step five of the steps made by the circulator, surgeon and surgical tech during the transfer of medications
The medication is transferred to the sterile field using the appropriate method of transfer. The following is detailed information related to transfer of medications. A syringe and hypodermic needle are frequently used by the surgeon to inject medications.
Step six of the steps made by the circulator, surgeon and surgical tech during the transfer of medications
Once the medication is delivered to the sterile field, the circulator will hold the medication container so that both individuals can see the label. The surgical technologist will read out loud the name of the drug, strength of the drug, and expiration date (third identification/verification).
Step seven of the steps made by the circulator, surgeon and surgical tech during the transfer of medications
The drug(s) is/are immediately labeled with the medication name and concentration on the sterile field. Many individual and commercial techniques for labeling are available
If any question exists regarding the identity or strength of a medication on the back table or Mayo stand, it MUST be discarded immediately and replaced
Step eight of the steps made by the circulator, surgeon and surgical tech during the transfer of medications
Every time the surgical technologist passes a medication to the surgeon for use, the name of the drug, strength, and amount are stated. All team members should be aware that a medication is being administered; it may be particularly important for the anesthesia provider to be informed that a drug (e.g., epinephrine) is in use.
Adrenergics
Generic Name: epinephrine
Trade Name: Adrenalin Chloride
Action: Causes vasoconstriction, resulting in reduced blood flow
Indication: Superficial bleeding; prolongs the effect of local anesthetics.
Surgical Use: Topical hemostasis; added to local anesthesia to prolong effect
Dosage: Topical: solution of 1:1,000 applied with Kittner sponge or neurosurgical cottonoid to bleeding area—NEVER INJECTED! In local anesthesia: concentrations of 1:500,000 to 1:50,000, with most common being 1:100,000 and 1:200,000
Analgesics (narcotic analgesics)
Generic Name: fentanyl citrate
Trade Name: Sublimaze
Action: Stimulates the opioid receptors in the CNS, resulting in pain relief
Indication: Moderate to severe pain
Surgical Use: Adjunct to general or regional anesthesia
Dosage: 0.5–1 mcg/kg IV over several minutes
Analgesic-antipyretic-nonsteroidal anti-inflammatory (NSAID) agents
Generic Name: Tromethamine
Trade Name: Toradol
Action:NSAID that provides pain relief
Indication: Short-term moderately severe pain management
Surgical Use:Postoperative pain management
Dosage: 60 mg IM or 30 mg IV
Antibiotic/Anti Infective Agent
Cephalosporins
Generic Name: cefazolin sodium cephalexin monohydrate
Trade Name: Ancef Kefzol Keflex
Action: 1st-generation cephalosporin; inhibits cell wall synthesis
Indication: Treatment of infection of respiratory, biliary, and GU tracts; skin, soft tissue, or bone/joint infection; septicemia
Surgical Use: Surgical prophylaxis; sepsis
Dosage: 250 mg to 1.5 g IM or IV every 6–8 hours
Anticoaguation atagonist
Generic Name: Protamine Sulfate
Trade Name: Protamine Sulfate
Action: An anticoagulant by itself; binds with heparin to inactivate heparin’s effect
Indication: Heparin reversal
Surgical Use: Reverses the effects of hep-arin sodium
Doasge: 1 mg for each 90–115 units of heparin given; not to exceed 50 mg
Coagulant
Generic Name: vitamin K
Trade name: AquaMephyton
Action: Increases the synthesis of prothrombin in the liver to promote clot formation
Indication: Hypoprothrombinemia
Surgical Use: Promote clot formation
Dosage: 2.5–10 mg IM up to 50 mg
Contrast media
Generic Name: diatrizoate me-glumine; diatri-zoate sodium; hypaque meglumine
Trade name: Cystografin; Hypaque; Renografin
Action: Block full penetration of ionizing radiation (X-ray, fluoroscopy)
Indication: Outline hollow structures for visualization during ra-diologic examinations
Surgical Use: Outline structures during biliary or urinary surgical interventions
Dosage: May be used full strength or diluted; dose depends on structure and number of radiographic images
Diuretics
Generic Name:mannitol
Trade Name: Osmitrol
Action: Osmotic diuretic that inhibits reabsorption of water and electrolytes
Indication: Generalized edema, oligouria; impaired renal function
Surgical Uses: Decrease intracranial pressure (ICP), intraocular pressure (IOP), or generalized fluid retention/edema
Dosage: 1.5–2 g/kg IV over 30–60 minutes
MH antagonist
Generic Name: dantrolene sodium
Trade Name: Dantrium
Action: Interferes with calcium transportation in skeletal muscle, reducing contraction
Indication: Malignant hyperthermia
Surgical Use: Management of malignant hyperthermia (MH)
Dosage: 2.5 mg/kg initial dose; max dose 10–30 mg/kg as indicated by patient condition