01 Concept of Medication Therapy

8/13/2019 01 Concept of Medication Therapy

1/145

Concept of Medication

Therapy

By

Arif Muttaqin, S. Kep, Ns, MMRS


2/145

Drug Names

Chemical name Describes the drugs chemical composition and

molecular structure

Generic name(nonproprietary name) Name given by the United States AdoptedName Council

Trade name(proprietary name)

The drug has a registered trademark; use of the namerestricted by the drugs patent owner(usually the manufacturer)


3/145

Drug Names (cont'd)

Chemical name (+/-)-2-(p-isobutylphenyl) propionic acid

Generic name ibuprofen

Trade name

Motrin, Advil


4/145

Quality use of medicine

The quality use of medicines refers to the process of: selecting patient management options wisely

choosing suitable medicines if a medicine is considered necessary

using medicines safely and effectively.

This definition of quality use of medicine not only applies

to medicines in the general practice setting, but also toall medicines used by individual patients that can affecttheir health. This whole-health system view is necessaryas general practice patients obtain their medicationsfrom a range of sources such as those initiated by

themselves, other general practitioners, other medicalspecialists, pharmacists and complementary therapists.


5/145

Pharmacokinetics

Pharmacokineticsis the way thebody acts on thedrug once it is

administered. It isthe measure ofthe rate (kinetics)of absorption,distribution,

metabolism andexcretion(ADME).


6/145

Absorption

Absorption is the movement of a drug fromits site of administration into the blood.

Most drugs are absorbed by passive

absorption but some drugs need carriermediated transport.

Small molecules diffuse more rapidly than

large molecules. Lipid soluble nonionized drugs are absorbed faster.

Absorption is affected by blood flow, painstress etc.


7/145

Absorption

Acidic drugs such as asprin will be better absorbed in the stomach whereas basic drug ikemorphine will be absorbed better in the intestine. Most of the absorption of the drug takes place inthe small intestine. Since the surface area of the stomach is much smaller than that of theintestine. Most of the drugs are absorbed in the small intestine since the amount of time that thedrugs spend in the stomach is less and also the surface area of the stomach is small. If a basicdrug is taken after a meal then the activity of the drug can be reduced whereas if an acidic drug istaken after a meal then the action of the can be noticed much more quickly, owing to the gastricabsorption.

For a drug even though lipophilic to be absorbed in the intestine some portion of it needs to bedissolved in the intestinal juices which are aqueous. There are some substances that are partlysoluble in water and it is these that will be absorbed and then an equivalent amount will beabsorbed from the undissolved portion. Thus complete absorption will take place. There are bilesalts present in the intestine which will aid in salvation of the drug and their resultant absorption.Drugs that are amphipathic have no problem in getting absorbed. There are some drugs that arecompletely insoluble in water such drugs float as globules in the intestine but the bile salts willemulsify these into small enough particles such that absorption can take place. E.g. vitamins.Some of the drugs are similar to compounds found in the body for e.g. thyroxine and such drugscan be absorbed into the system by active transport.

When drugs are injected into the muscle, subcutaneous layer absorption still has to take place butit is less dependent on the chemical nature of the drugs since the drugs are absorbed into thecirculatory system through the small pores in the capillary walls.


8/145

Distribution

Distribution is the movement of drugs

throughout the body. Determined by the

blood flow to the tissues, it is ability of the

drug to enter the vasculature system andthe ability of the drug to enter the cell if

required.


9/145

Plasma Protein Binding

The blood stream has the ability to transport relatively insoluble substances.

These substances are transferred by binding to the proteins which have avery amphipathic structure. The hydrophilic group renders the proteinsoluble in water and the lipophilic compounds are attracted to the lipophilicgroup and are loosely bound to the protein molecule hence protein bound.Most of the drugs travel in the plasma are partly in solution and partly boundto the plasma protein. The bound drug is inactive and the unbound drug is

active. The ratio of bound to the unbound drug varies. Binding is reversible.Generally acidic drugs bind to albumin and basic drugs to 1 acidglycoprotein. Diseased state can cause a problem on the effectiveness ofthe drug. As globin levels increase with age this factor should be taken intoaccount when treating an elderly person with a basic drug.

The protein bound drug is in equilibrium with the free drug. That means thatonce the free drug enters the target tissue then the protein bound drug willbe released to maintain equilibrium. If two drugs bind at the same site of theprotein and are administered together then there can be problems. e.g.Warfarin and asprin.. asprin displaces warfarin from its bound protein as aresult of which there are elevated levels of warfarin in the unbound stateand this can lead to warfarin toxicity.


10/145

Tissue Distribution

After absorption most drugs are distributed

in the blood to the body tissue where they

have their effect. The degree to which the

drug is likely to accumulate in the tissue isdependent on the lipophilicity and local

blood flow to the tissue. Highly perfused

organs receive most of the drugs.


11/145

The role of the liver in drug distribution

After the drug is absorbed by the GI tract, it is taken upby the part of the bloodstream called the hepatic portalsystem. Most of the drugs are absorbed into this systemexcept for the lipids which are absorbed into thelymphatic system and then delivered into the blood by

the thoracic duct into the superior vena cava. The hepatic portal system is designed to take digested

foodstuff into the liver where it can be processed, insome cases it is stored before being distributed and it ispossible that this may happen to the drug and the drug

would be metabolized before reaching the rest of thebody. Such drugs that metabolized by the liver are saidto have a high hepatic first pass. Hence drugs with avery high hepatic first pass cannot be given orally.


12/145

The BloodBrain Barrier (BBB)

The capillaries in the CNS are different they have poreswhich are sealed by the connective tissue and henceonly small molecules can cross the blood brain barrierand the substances that can cross over have to be verylipophilic in nature. The blood-brain barrier (BBB) is the

protective mechanism of the CNS and is not presenteverywhere in the brain. This is sometimes useful as itavoids some drugs from crossing the CNS and causingdeleterious effects.

E.g. neuromuscular blocking agents. Sometimes the

blood brain barrier allows the transport of drugs resultingin unwanted effect for e.g. antihistamines cross the bbband result in drowsiness, now there are antihistaminesthat are made that are not so lipophilic in nature.


13/145

Metabolism or Biotransformation

It is the process of transformation of a drug within the body to makeit more hydrophilic so that it can be excreted out from the body bythe kidneys. This needs to be done since drugs and chemicals areforeign substances in our body. If the drug continues to be in thelipohilic state and is going to be filtered by the glomerulus then it willbe reabsorbed and remain in the body for prolonged periods. Hence

metabolism deals with making the drug more hydrophilic such that itcan be excreted out from the body. In some cases the metabolitescan be more active than the drug itself e.g. anxiolyticbenzodiazepines.

Some enzymes are highly specific and will breakdown onlycompounds that they recognize for e.g. glucose dehydrogenase. But

there are some enzymes such as pepsin which are not specific andwill breakdown most soluble proteins into smaller polypeptides oramino acids. This enzyme and many other proteolytic enzymesattack the peptide bond that joins the amino acids to make proteins,and in this way break the protein down.


14/145

Two types of enzymes are involved in metabolism:

Phase I Metabolism These enzymes modify the drug chemically by processes such as

oxidation, reduction and hydrolysis or by the removal and addition of anactive group.

Phase II Metabo lism These include the conjugation of a drug or a phase I metabolite with a

polar group to render it possible for excretion. e.g. sulphates andglucuronide

The deconjugation of the drug by bacterial enzymes is called theenterohepatic cycle. Sometimes this deconjugation can lead toincreased levels of drugs in the body. But some times due to

treatment with antibiotics there may be less or no deconjugation asa result of which there will be less drug in the body.

Principal sites of metabolism are Liver and Kidney and once thedrug is rendered hydrophilic they can be easily excreted out by thebile and urine without significant reabsorption.


15/145

Enzyme

Enzyme Induction

There are some drugs that can lead to an increase in

the production of the enzyme and as a result speed

up the metabolism of the drug and hence a higherdose of the drug is required to achieve the therapeutic

effect.

Enzyme Inhibition

Some drugs result in the inhibition of certain enzymesand as a result there is an accumulation of the drug in

the body and can lead to drug toxicity. This is also a

form of drugdrug interaction.


16/145

Excretion

Excretion is the removal of the substance fromthe body.

Some drugs are either excreted out unchangedor some are excreted out as metabolites in urine

or bile. Drugs may also leave the body bynatural routes such as tears, sweat, breath andsaliva.

Patients with kidney or liver problem can have

elevated levels of drug in the system and it maybe necessary to monitor the dose of the drugappropriately since a high dose in the blood canlead to drug


17/145

1. You are caring for a client who has diabetes complicated bykidney disease. You will need to make a detailed assessmentwhen administering medications because this client mayexperience problems with:

A. Absorption

B. Biotransformation

C. Distribution

D. Excretion

35 - 17


18/145

Pharmacodynamics

Study of the mechanism of drug actions in

living tissue

Drug-induced alterations to normal

physiologic function

Positive change-Therapeutic effect-Goal of

therapy


19/145

Mechanism of Action

Ways in which a drug can produce atherapeutic effect

The effects that a particular drug has

depends on the cells or organ targeted bythe drug

Once the drug hits its site of action it canmodify the rate at which a cell or tissue

functions


20/145

Mechanism of Action

Receptor Interaction

Enzyme Interaction

Non-Specific Interaction


21/145


Drug structure is essential

Involves the selective joining of drugmolecule with a reactive site on the cell

surface that elicits a biological effect Receptor is the reactive site on a cell or

tissue

Once the substance binds to and interactswith the receptor, a pharmacologicresponse is produced


22/145


Affinity- degree to which a drug binds with areceptor

The drug with the best fit or affinity will elicit thebest response

Drug can mimic bodys endogenous substancesthat normally bind to receptor site

Drugs that bind to receptors interact withreceptors in different ways to either block or elicit

a response


23/145


24/145


25/145

Enzyme Interaction

Enzymes are substances that catalyze nearlyevery biochemical reaction in a cell

Drugs can interact with enzyme systems to alter

a response Inhibits action of enzymes-enzyme is fooledinto binding to drug instead of target cell

Protects target cell from enzymes action (ACE

Inhibitors)


26/145

Non-Specific Interaction

Not involving a receptor site or alteration inenzyme function

Main site of action is cell membrane or cellular

process Drugs will physically interfere or chemically altercell process

Final product is altered causing defect or cell

death Cancer drugs, Antibiotics


27/145


28/145

The nurse is giving a medication that has a

high first-pass effect. The physician has

changed the route from IV to PO. The nurseexpects the oral dose to be:

1. Higher because of the first-pass effect.

2. Lower because of the first-pass effect.

3. The same as the IV dose.

4. Unchanged.


29/145


30/145

Therapeutic Effect

The expected or predictable physiologicalresponse a medication causes

A single med can have several therapeutic

effects (Aspirin) It is important for the nurse to know why

med is being prescribed


31/145

Side Effects

Unintended secondary effects a medication

predictably will cause

May be harmless or serious

If side effects are serious enough to negate thebeneficial effect of meds therapeutic action, it

may be D/Cd

People may stop taking medications because ofthe side effects


32/145

Adverse Effects

Undesirable response of a medication

Unexpected effects of drug not related totherapeutic effect

Must be reported to FDA Can be a side effect or a harmful effect

Can be categorized as pharmacologic,idiosyncratic, hypersensitivity, or drug interaction


33/145

Adverse Effects

Adverse Drug Events

Adverse Drug Reactions (ADR)


34/145

Toxic Effect

May develop after prolonged intake or when a

med accumulates in the blood because of

impaired metabolism or excretion, or excessive

amount taken Toxic levels of opioids can cause

resp.depression

Antidotes available to reverse effects


35/145

Idiosyncratic Reactions

Unpredictable effects-overreacts or under reacts

to a medication or has a reaction different from

normal

Genetically determined abnormal response Idiosyncratic drug reactions are usually caused

by abnormal levels of drug-metabolizing

enzymes (deficiency or overabundance)


36/145

Allergic Reaction

Unpredictable response to a medication

Makes up greater than 10% of all medicationreactions

Client may become sensitized immunologicallyto the initial dose, repeated administrationcauses an allergic response to the med,chemical preservative or a metabolite


37/145

Allergic Reaction

Medication acts as an antigen triggering therelease of the bodys antibodies

May be mild or severe

Among the different classes of meds, antibioticscause the highest incidence of allergic reaction

Severe reaction-Anaphylactic reaction

Mild reaction-hives, rash, pruritis


38/145


39/145


40/145


41/145

Other Drug Reactions

Teratogenic-Structural effect in unborn

fetus (thalidomide)

Carcinogenic-Causes cancer

Mutagenic- Changes genetic composition

(radiation, chemicals)


42/145

Drug Interactions

Occurs when one med modifies the actionof another

Common in people taking several

medications at once One med may potentiate or diminish theaction of another or alter the way it isabsorbed, metabolized or eliminated


43/145

Iatrogenic Responses

Unintentional adverse effects that occur duringtherapy

Treatment-Induced Dermatologic-rash, hives,acne

Renal Damage-Aminoglycoside antibiotics,NSAIDS, contrast medium

Blood Dyscrasias- Destruction of blood cells(Chemotherapy)

Hepatic Toxicity-Elevated liver enzymes(hepatitis-like symptoms)


44/145

Synergistic Effect

Effect of 2 meds combined is greater than themeds given separately

Alcohol & Antihistamines, antidepressants,barbiturates, narcotics

Not always undesirable, physician may combinemeds to create an interaction that will havebeneficial effects (Vasodilators & diuretics tocontrol high BP)


45/145


46/145

Medication Dose Responses

Serum Half-Life:Time it takes for excretionprocesses to lower the serum medicationconcentration by

Regular fixed doses must be given to maintaintherapeutic concentration

Dosage schedules set by institutions (TID, q8h,HS, AC, STAT, PRN)

Peak & Trough levels Therapeutic drug monitoring


47/145

Half-life

The time it takes for one half of the original

amount of a drug in the body to be removed

A measure of the rate at which drugs are

removed from the body


48/145


49/145

Pharmacotherapeutics:

Types of Therapies Acute therapy

Maintenance therapy Supplemental therapy

Palliative therapy

Supportive therapy

Prophylactic therapy


50/145

Monitoring

The effectiveness of the drug therapy must

be evaluated

One must be familiar with the drugs:

Intended therapeutic action (beneficial)

Unintended but potential side effects

(predictable, adverse reactions)


51/145

Monitoring (cont'd)

Therapeutic indexThe ratio between a drugs therapeutic benefits and its toxiceffects

Interactions may occur with other drugs or food Drug interactions: the alteration of action of

a drug by:

Other prescribed drugs

Over-the-counter medications

Herbal therapies

Drug interactionsAdditive effect

Synergistic effectAntagonistic effect

Incompatibility


52/145

Monitoring (cont'd)

Medication misadventures

Adverse drug events

Adverse drug reactions

Medication errors


53/145

Monitoring (cont'd)

Some adverse drug reactions are

classified as side effects

Expected, well-known reactions that result in

little or no change in patient management

Predictable frequency

The effects intensity and occurrence are related

to the size of the dose


54/145

Adverse Drug Reaction

An adverse outcome of drug therapy in

which a patient is harmed in some way

Pharmacologic reactions

Idiosyncratic reactions

Hypersensitivity reactions

Drug interactions


55/145


56/145

Toxicology

The study of poisons and unwanted

responses to therapeutic agents


57/145

Table 2-9 Common

Poisons and Antidotes


58/145

2. A postoperative client is receiving morphine sulfate via aPCA. The nurse assesses that the clients respirations aredepressed. The effects of the morphine sulfate can be classifiedas:

A. Allergic

B. Idiosyncratic C. Therapeutic

D. Toxic

35 - 58

Fi t P Eff t


59/145

First-Pass Effect The metabolism of a

drug and its passagefrom the liver into thecirculation A drug given via the

oral route may be

extensivelymetabolized by theliver before reachingthe systemiccirculation (high first-pass effect)

The same druggivenIVbypasses the liver,preventing the first-pass effect from takingplace, and more drugreaches the circulation


60/145

Routes of drug administration Enteral route

Parenteral route

Inhalation

Topical


61/145

Enteral Route:

Enteral route is through the alimentary canal.

It might be:

Oral

Sublingual Per rectum


62/145

Oral Route: Oral route is the most common route of drug administration. It is mostly

used for the neutral drugs. It may be in the form of tablets, capsules, syrup,emulsions or powders.

Advantages: It is convenient

It is the cheapest available route

It is easy to use

It is safe and acceptable.

Disadvantages: Less amount of drugreaches the target tissue. Some of the drugis destroyed by gastric juices e.g. adrenaline, insulin, oxytocin

Absorptionhas to take place which is slow, so is not preferred during emergency.

It might cause gastric irritation

It might be objectionable in taste.

It might cause discoloration of teeth e.g. iron causes staining, tetracyclines below 14cause brown discoloration so are not advisable during pregnancy.

First Pass Effect: First pass effect is the term used for hepatic metabolism

of drugwhen absorbedand delivered through portal blood. Greater the firstpass effect, less amounts of the drug reach the systemic circulation.
http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/


63/145

Sublingual Route:

Sublingual route involves tablets placed under the tongue orbetween cheeks or Gingiva. The drugshould be lipid soluble andsmall.

Advantages: Rapid absorptiontakes place.

Drugis dissolved easily

Drugenters the blood directly Less first pass effect.

Spitting out of the drugremoves its effect

Disadvantages: This method is inconvenient.

Irritation of the mucous membrane might occur

Person may swallow the drug

Might be unpleasant in taste.

Examples of drugsgiven by this route include nitroglycerin,isoprenaline and oxytocin. Nifedipine used for the treatment ofhypertension in emergency is given by sublingual route.
http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/drug/


64/145

Rectal Route:

Drugsin solid forms such as suppositories or in liquidforms such as enema are given by this route. This routeis mostly used in old patients. Drugsmay have local orsystemic actions after absorption.

Advantages: This route is preferred in unconscious or uncooperative patients.

This route avoids nausea or vomiting Drug cannot be destroyed by enzymes.

This route is preferred if drugis irritant.

Disadvantages: This route is generally not acceptable by the patients.

Locally acting drugs include glycerin and Bisacodyl suppository Systemic acting drugs include Indomethacin (anti inflammatory) and

aminophyllin (bronchodilator)

Retention enema is diagnostic and is used for finding the pathologyof lower intestines.

Drugsgiven by rectal route have 50% first pass metabolism.
http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/


65/145

Parenteral Route:

Parenteral route includes: Injections:

Intra muscular

Intra venous

Intra-arterial Intra-cardiac

Intra-thecal

Intraosseous- into bone marrow

Intrapleural

Intraperitoneal Intra-articular

Intradermal (Intracutaneous)

Subcutaneous route (Hypodermic)


66/145

Classification: Site of Release:

Site of release may be intradermal, intraperitoneal, intrapleural, intracardiac, intra-arterial, intrathecal (into meninges of spinal cord), intra-articular (into joint cavity).

a. Subcutaneous: Subcutaneous route might be used for the arm, forearm, thigh and subscapular space.

The volume used is 2 ml. Insoluble suspensions like insulinand solids might be applied bythis route.

Advantages: Absorptionis slow and constant

It is hygienic Disadvantages:

It might lead to abscess formation

Absorptionis limited by blood flow

Examples of drugs given by subcutaneous route include insulin, adrenaline and norplant.

b. Intramuscular route: Intramuscular route might be applied to the buttock, thigh and deltoid. The volume used is 3

ml.

Advantages: Absorptionis rapid than subcutaneous route.

Oily preparations can be used.

Irritative substances might be given

Slow releasing drugscan be given by this route.

Disadvantages Using this route might cause nerve or vein damage.
http://howmed.net/physiology/insulin/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/physiology/insulin/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/physiology/insulin/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/physiology/insulin/


67/145

Classification:

c. Intravenous injections: Intravenous injections might be applied to the cubital, basilic and cephalic veins.

Advantages: Immediate action takes place

This route is preferred in emergency situations

This route is preferred for unconscious patients.

Titration of dose is possible.

Large volume of fluids might be injected by this route Diluted irritant might be injected

Absorptionis not required

No first pass effect takes place.

Blood plasma or fluids might be injected.

Disadvantages: There is no retreat

This method is more risky

Sepsis-Infection might occur

Phlebitis(Inflammation of the blood vessel) might occur

Infiltration of surrounding tissues might result.

This method is not suitable for oily preparations

This method is not suitable for insoluble preparations
http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/absorption-of-drugs/


68/145


69/145

Inhalation

Inhalation may be the route of choice to avoid thesystemic effects. In this way drugscan pass directly tothe lungs.Drugsused involve volatile drugs and gases.Examples include aerosols like salbutamol; steaminhalations include tincture and Benzoin

Advantages: Rapid absorptiontakes place.

Rapid onset of action takes place.

This route has minimum side effects.

No first pass effect takes place.

This method is easy.

Fewer doses is required.

Disadvantages: Special apparatus is required.

Irritation of the respiratory tract may take place.

Cooperation of the patient is required.

Airway must be patent.
http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/absorption-of-drugs/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/


70/145

Topical route Drugsmay be applied to the external surfaces, the skin and the mucous

membranes. Topical route includes: a. Enepidermic route When the drugis applied to the outer skin, it is called enepidermic route of drug

administration. Examples include poultices, plasters, creams and ointments.

b. Epidermic route (Innunition): When the drugis rubbed into the skin, it is known as epidermic route. Examples

include different oils.

c. Insufflations: When drugin finely powdered form is blown into the body cavities or spaces with

special nebulizer, the method is known as insufflations.

d. Instillation Liquids may be poured into the body by a dropper into the conjunctival sac, ear,

nose and wounds. Solids may also be administered.

e. Irrigation or Douching

This method is used for washing a cavity e.g. urinary bladder, uterus, vagina andurethra. It is also used for application of antiseptic drugs.

f. Painting/Swabbing Drugsare simply applied in the form of lotion on cutaneous or mucosal surfaces

of buccal, nasal cavity and other internal organs.

Time of Action using Different
http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/


71/145

Time of Action using Different

Routes of Administration

Drugstake different time durations after injectionusing different routes to perform their actions.

This time delay is important, oral route has

controlled release time, thus depot or reservoirpreparation may be made e.g. penicillin for

rheumatic fever.

Usage of drugdepends on its physical

properties, chemical properties, speed of action,need and bypass effect.
http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/http://howmed.net/pharmacology/drug/


72/145

Some of the approximate time intervals are given below:

Route of Drug Administration Delay time for Action

Intravenous route 30-60 seconds

Intraosseous route 30-60 seconds

Endotracheal inhalation 2-3 minutes

Sublingual route 3-5 minutes

Intramuscular route 10-20 minutes

Rectal route 5-30 minutes

Ingestion 30-90 minutes

System of medication


73/145

System of medication

measurements

Metric System

Apothecary System

Household System


74/145

Metric System

Basic unit of solid measurement is the gram,basic unit of liquid measurement is the liter, and

basic unit of length measurement is the meter.

Variations of these measurements will includethe prefixes of kilo, centi, deci, milli, micro etc.

Unit of measure follows the number

Arabic numbers are used

Fractions are expressed as decimals

Example notations: 3 g; 0.25 mg; 500 mL


75/145

The Apothecary System

Basic unit of solid measurement is the grain and basicunits of liquid measurement include minim, dram, andfluid ounce.

Unit of measure precedes the number

Roman numerals are used for smaller numbers. Arabicnumbers are more commonly used if larger numbers.

Fractions are expressed as numerical fractions. A small"ss" may be used to represent 1/2.

Example notations: gr iiss; drams 3 (NOTE: There aresymbols to represent dram and ounce which cannot bereproduced here. Refer to page 9 in the Drug DosageLab document to see these symbols.)


76/145

Household system

Basic units of solid measurement arepounds and ounces and units of liquidmeasurement include teaspoon,

tablespoon, cups, etc. Unit of measure follows the number

Arabic numbers are used

Fractions are expressed as numericalfractions

Example notations: 1/2 t; 125 lbs

The Nursing


77/145

The NursingProcess

Assessment

Nursing diagnosis

Planning (with outcome criteria)

Implementation

Evaluation

The Nursing Process (cont'd)


78/145

The Nursing Process (cont d)

Assessment

Data collection

Subjective, objective

Data collected on the patient, drug, environment

Medication history

Nursing assessment

Physical assessment Data analysis

Th S


79/145

The Seven

Rights Right drug

Right dose Right time

Right route

Right patient Right to refuse

Right documentation

Another


80/145

Another

Right

Constant

System

Analysis

A double-check

The entire system ofmedication administration

Ordering, dispensing,preparing, administering,documenting

Involves the physician,nurse, nursing unit,pharmacy department,and patient education

Other Rights


81/145

Other Rights

Proper drug storage

Proper documentation

Accurate dosage calculation

Accurate dosage preparation

Careful checking of transcription of orders

Patient safety

Other Rights (cont'd)


82/145

Other Rights (cont d)

Close consideration of special situations

Prevention and reporting of medication

errors

Patient teaching

Monitoring for therapeutic effects, side

effects, toxic effects

Refusal of medication

Evaluation


83/145

Evaluation

Ongoing part of the nursing process

Determining the status of the goals and

outcomes of care

Monitoring the patients response to drug

therapy

Expected and unexpected responses


84/145

The day shift charge nurse is making rounds. Apatient tells the nurse that the night shift nurse

never gave him his medication, which was due at

11 PM. What should the nurse do first to

determine whether the medication was given?

1. Call the night nurse at home.

2. Check the Medication Administration Record.

3. Call the pharmacy.

4. Review the nurses notes.


85/145

The patients Medication Administration Recordlists two antiepileptic medications that are due at

0900, but the patient is NPO for a barium study.

The nurses coworker suggests giving the

medications via IV because the patient is NPO.What should the nurse do?

1. Give the medications PO with a small sip of water.

2. Give the medications via the IV route because the

patient is NPO.3. Hold the medications until after the test is

completed.

4. Call the physician to clarify the instructions.

Life Span Considerations


86/145

Life Span Considerations

Pregnancy

Breast-feeding

Neonatal

Pediatric

Geriatric

Pregnancy


87/145

Pregnancy

First trimester is the period of greatestdanger for drug-induced developmental

defects

Drugs diffuse across the placenta FDA pregnancy safety categories


88/145

Table 3-1

Pre nanc

Breast-feeding


89/145

Breast feeding

Breast-fed infants are at risk for exposureto drugs consumed by the mother

Consider risk-to-benefit ratio


90/145

Pediatric Considerations:


91/145


Pharmacokinetics

Absorption

Gastric pH less acidic

Gastric emptying is slowed Topical absorption faster through the skin

Intramuscular absorption faster and irregular



92/145


Pharmacokinetics (cont'd)

Distribution

TBW 70% to 80% in full-term infants, 85%in premature newborns, 64% in children

1 to 12 years of age

Greater TBW means fat content is lower Decreased level of protein binding

Immature blood-brain barrier



93/145



Metabolism

Liver immature, does not produce enough

microsomal enzymes

Older children may have increased

metabolism, requiring higher doses

Other factors



94/145



Excretion

Kidney immaturity affects glomerular filtrationrate and tubular secretion

Decreased perfusion rate of the kidneys

Summary of Pediatric


95/145

y

Considerations

Skin is thin and permeable

Stomach lacks acid to kill bacteria

Lungs lack mucus barriers

Body temperatures poorlyregulated and dehydration occurseasily

Liver and kidneys are immature,impairing drug metabolism andexcretion


96/145

Methods of Dosage Calculation for

Pediatric Patients

Body weight dosage calculations

Body surface area method


97/145

Geriatric Considerations


98/145

Geriatric Considerations

Geriatric: older than age 65 Healthy People 2010: older than age 55

Use of OTC medications

Polypharmacy


99/145

Geriatric Considerations:


100/145

Pharmacokinetics

Absorption

Gastric pH less acidic

Slowed gastric emptying

Movement through GI tractslower

Reduced blood flow to the

GI tract Reduced absorptive

surface area due to

flattened intestinal villi



101/145



Distribution

TBW percentages lower

Fat content increased

Decreased production of proteins by the liver,

resulting in decreased protein binding ofdrugs



102/145


Metabolism

Aging liver produces less microsomal

enzymes, affecting drug metabolism

Reduced blood flow to the liver



103/145



Excretion

Decreased glomerular filtration rate

Decreased number of intact nephrons

Geriatric Considerations: Problematic


104/145

Medications

Analgesics

Anticoagulants

Anticholinergics

Antihypertensives

Digoxin

Sedatives and hypnotics

Thiazide diuretics

Ethical Nursing Practice


105/145

g

American Nurses Association (ANA) Codeof Ethics for Nurses

Cultural Considerations


106/145

Assess the influence of a

patients cultural beliefs,values, and customs

Drug polymorphism

Compliance level with

therapy Environmental

considerations

Genetic factors

Varying responses tospecific agents

Cultural Assessment


107/145

Health beliefs and practices

Past uses of medicine

Folk remedies

Home remedies

Use of nonprescription drugs and herbal

remedies

OTC treatments

Cultural Assessment

( t'd)


108/145

(cont'd)

Usual response to treatment

Responsiveness to medical treatment

Religious practices and beliefs

Dietary habits


109/145

Preparing for Drug

Ad i i t ti


110/145

Administration

Check the 7 rights

Standard Precautions: Wash your hands!

Double-check if unsure about anything

Check for drug allergies

Prepare drugs for one patient at a time

Check three times Check expiration dates

Check the patients identification (2 identifiers)

Give medications on time

Explain medications to the patient Open the medications at the bedside

Document the medications given before going to thenext patient


111/145


112/145


113/145

Enteral Drugs


114/145

Enteral Drugs

Giving oral medications

Giving sublingual or buccal medications

Liquid medications

Giving oral medications to infants

Administering drugs through a

nasogastric or gastrostomy tube

Rectal administration


115/145

Parenteral Drugs


116/145

g

Never recap a used needle! May recap an unused needle with the scoop

method

Prevention of needlesticks

Filter needles

Removing medications from ampules

Removing medications from vials

Disposal of used needles and syringes Needle Selection


117/145


118/145


119/145


120/145

Injections


121/145

Injections

Needle angles for various injections Intramuscular (IM)

Subcutaneous (SC or SQ)

Intradermal (ID)

Z-track method for IM injections

Air-lock technique


122/145


123/145


124/145

Injection Techniques


125/145


Intradermal injections

Subcutaneous injections Insulin administrationAnticoagulant administration (Heparin/Lovenox)


126/145


127/145


128/145



129/145

j q

(cont'd) Intramuscular injections Ventrogluteal site (preferred)

Vastus lateralis site

Dorsogluteal site Deltoid site


130/145

Preparing

Intra eno s


131/145

Intravenous

Medications Needleless systems

Compatibility issues

Expiration dates

Mixing intravenouspiggyback (IVPB)medications

Labeling intravenous(IV) infusion bags whenadding medications


132/145


133/145


134/145


135/145


136/145

Intravenous

M di i


137/145

Medications

(cont'd) Volume-controlled administration set

Using electronic infusion pumps

Patient-controlled analgesia (PCA) pumps


138/145

Topical Drugs


139/145

p g

Eye medications Drops

Ointments

Ear drops

Adults

Infant or child younger than3 years of age


140/145

Topical Drugs (cont'd)


141/145

p g ( )

Nasal drugs Drops

Spray

Inhaled drugs

Metered-dose inhalers

Small-volume nebulizers


142/145


143/145


144/145


145/145

Documents

01 Concept of Medication Therapy