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