pharmacology usb 2

8/2/2019 Pharmacology Usb 2

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UNIT II

Chemotherapeutic

Drugs


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Chemotherapeutic drugsare used

1. to destroy both organisms that invade

the body (bacteria, parasites, protozoa,

etc)

2. and, abnormal cells within the body

(neoplasms or cancer)


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Review

of the

cell physiology


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The cell

- is the basic structural unit of the

body- it has a nucleus, cell membrane,and cytoplasm


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The nucleus

- contains all the genetic materials

necessary for cell reproduction

- regulates cellular production ofspecific proteins to carry out the

cells functions ( maintenance of

cell homeostasis & promotion of

cell division)


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The Cell Membrane

- a thin barrier which surrounds the

cell

- separates the extracellular and

intracellular fluids

- essential for cellular integrity


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- consists of lipoprotein structure

which allow the membrane to act as

a barrier in keeping the cytoplasm

within the cell and regulates what

can enter the cell


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Receptor sites

- are embedded in the lipoprotein layer

of the cell membrane

- reacts with specific chemicals outside

the cell to stimulate a reaction within a

cell


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- very important in the functioning of the

neurons, muscle cells, endocrine glands &

other cell types

- play a very important role in clinical

pharmacology


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Histocmpatibility antigens or human leukocytes

antigens (HLAs)

- the body uses this to identify a cell as aself-cell (a cell belonging to the individual)

- bodys immune system recognizes these

proteins & acts to protect self-cell and

destroy non self-cells


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- if the markers are altered, the bodys

immune system reacts to the change &

can ignore it, allowing neoplasms to grow

and develop

- the immune system my also attack the

cell leading to many problems associated

with autoimmune disorders, & chronic

inflammatory conditions


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Channels are pores within the cell membrane

that allow passage of small substances in

or out of the cell.

Example: specific channels for Na, K, Ca,

Cl, HCO3, and H2O


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The Cytoplasm

- lies within the cell membrane

- contains many structure with specific functions

(organelles)- Mitochondria, endoplasmic reticulum,

free ribosomes, golgi apparatus,lysosomes

- site of activities of cellular metabolism & specialcellular functions


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Mitochondria

- rod-shaped power plants within eachcell

- produces energy in the form of ATP

(used to maintain homeostasis,produce protein, & carry out specificfunctions

- very abundant in active cells (heartmuscles always contracting)


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- takes carbohydrates, fats, & proteins

from the cytoplasm and make ATP via

the Krebs cycle (which depends on

oxygen)

- if oxygen is not available, lactic acid

builds up as a byproduct of cellular

respiration


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Endoplasmic reticulum

- made up of fine network of

channel known as cisternae

(interconnected channels that form

the endoplasmic reticulum)


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- provides a large surface for chemical

reactions within the cell

- production of CHON, nonCHON,

hormones

- breakdown of many toxic

substances


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Lysosomes

- membrane covered organelles that

contain specific digestive enzymes

that can break down CHON, nucleic

acids, CHO, & lipids

- responsible for digesting worn &

damaged section of a cell

(encapsulation & self-digesting)


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- if cell dies & membrane ruptures, the

release of lysosomes causes the cell

to self-destruct

Golgi Apparatus

- flattened sacs that process and packs

hormones & other substances for

excretion


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Cell properties

> Endocytosis involves incorporation of

material into the cell> Pinocytosis a form of endocytosis-

engulfing of a specific substance that

have reacted with a receptor site- allows cells to absorb nutrients,

enzymes

> Phagocytosis (a neutrophil ormacrophage) allows cell to engulf abacterium or a foreign CHON & destroy itwithin the cell


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> Phagocytosis (a neutrophil or

macrophage) allows cell to engulf a

bacterium or a foreign CHON & destroy

it within the cell


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> Exocytosis allows a cell to move a

substance to the cell membrane & thensecrete the substance outside the cell

- hormones, neurotransmitters,enzymes, others are produced within a

cell & excreted into the body

> Homeostasis keeping the cytoplasm

stable within the cell membrane


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Chapter 1

Anti-infectives Agents


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Anti infective Agent/Antiinfectives

- drugs that act selectively on foreign

organism that have invaded and infectedthe body of a human host

- ideally, toxic to the infecting organisms

only & would have no effect on the host

cells


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Goal of giving Antiinfectives:

- interference with the normal functions

of the invading organism to prevent it

from reproducing and to cause cell

death without affecting the host cells.


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- reduction of the population of the

invading organisms to a point at which the

human immune response can take care of

the infection


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Spectrum the scope of effectivenessagainst invading organism

Narrow spectrum so selective in theiraction that they are effective againstonly a few microbes

Broad spectrum effective against manydifferent kinds of microbes, making

them useful in the treatment of awide variety of infections


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Drug of Choice

- specific anti infective that can affecta specific microbe more effectively

Resistance to the drug

- if the microbe is not affected by theparticular anti infective

- can be acquired through genetic

mutation, altered binding site, changein cellular permeability


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Preventing resistance can be done

through:

- Indiscriminate use of antimicrobials

- Proper dose and timing- Use first more established drugs before

using the newly introduced drugs

- Use drugs that cause least complications

- Culture and sensitivity test beforechemotherapy


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Combination therapy:

- a combination of 2 or more type ofdrugs that effectively treats the infection

- uses a smaller dosage of each drug,

leading to fewer adverse effects- some drugs are synergistic ( the

combined effect of 2 drugs is more

than that of each drug given alone)- for infections caused by more than 1

microbes


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- some drugs are synergistic ( the

combined effect of 2 drugs is more

than that of each drug given alone)

- for infections caused by more than 1

microbes


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Chapter 2

Antibiotics


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Antibiotics

- are chemicals that kill the bacteria

(bactericidal) or prevent the growth of

bacteria (bacteriostatic)

- maybe both bactericidal & bacteriostatic

depending on the concentration/dose

given


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- maybe made from living microorganisms,

synthetic manufacturing, & genetic

engineering


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Major classes of antibiotics:

1. Aminoglycosides

2. Cephalosporins

3. Fluoroquinolones

4. Lincosamides

5 . Macrolides6. Monobactams


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7. . Penicillin

8. . Penicillinase-resistant drugs

9. . Sulfonamides

10 . Tetracyclines

11. Antimycobacterial antibiotic

a. Antituberculosis Drugsb. Leprostatic Drugs


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1. Aminoglycosides

Mechanism of action:

Inhibit CHON synthesis in gram-

negative bacteria which leads to

loss of functional integrity of thebacterial cell membrane, causing cell

death


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Indications:

- infections caused by gram negative

bacteria

- treatment of infections susceptible

to penicillin when penicillin is

contraindicated


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Pharmacokinetics:

- poorly absorbed from the GI tractbut rapidly absorbed after IM

injection, reaching peak levels

within 1 hour.

- it cross the placenta and breast milk

barrier


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- excreted unchanged in the urine

and have an average half-life of 2 to

3 hours

- depends on the kidney for excretion

(toxic to the kidney)


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Contraindications & Cautions:

- known allergy to aminoglycosides

- renal & hepatic diseases

- pre-existing hearing loss,- active infection with herpes or

mycobacterial infections

- myasthenia gravis or parkinsonism- lactation, pregnancy


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- Children and older people are very

sensitive to the effects of most

antibiotic and more severe reactions

are expected

- Thrush is a common superinfection in

children

-


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Adverse Effects

- CN S effects: ototoxicity leading toirreversible deafness, vestibularparalysis, confusion, depression,disorientation, numbness, tingling,

weakness- R enal toxicity may progress to renalfailure

- B one marrow depression leading toimmune suppression and resultingto superinfection, fever, and so on


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- GI effects: Nausea, vomiting,

diarrhea, weight loss, stomatitis,

hepatic toxicity

- these are the results of GI irritation,

loss of normal bacterial flora

- Cardiac effects: palpitations,

hypotension, hypertension

- Hypersensitivity reactions: purpura,

rash, urticaria, exfoliative dermatitis


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Drug-drug Interaction:

- if taken with potent diuretics, there

is increase in the incidence of

ototoxicity, nephrotoxicity,

neurotoxicity. This should be avoided

if possible


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- if given with anesthetics,

nondepolarizing neuromuscular

blockers, citrate anticoagulated blood,

increased neuromuscular blockade

with paralysis is possible

- have a synergistic bactericidal effect

when given with penicillins,

cephalosporins,


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Nursing Considerations/Responsibilities

Assess

- F or allergic reaction to the drug

- History of renal or hepatic disease

- Pre-existing hearing loss

- Active infection with herpes, varicella,

fungal, mycobacterial organism,myasthenia gravis, parkinsonism

NURSING RESPONSIBILITIES


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Monitor super infections

Evaluate renal/liver functions

Diarrhea-take yogurt to prevent it

Inform provider prior to taking other meds

Culture & sensitivity prior to initial dose

Alcohol is out; Ask about allergy

Take full course of the drug

Evaluate culture, WBC, temp., blood dyscrasias& electrolytes


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MEDICATE

* Oral- 1 hour interval with other antibiotic

IV- dilute & administer slowly

* Audiograms; hearing test

EVALUATION

> Normal temperature, WBC & cultures

> (-) signs & symptoms of TB ( Streptomycin)

> Decreased ammonia level (Neomycin)


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- Current pregnancy or lactation status

- Physical assessment, vital signs to

establish baseline data

- Culture and sensitivity

- Give the correct dosage and timing- Apply the principles of medication

administration


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Educate adults

- that antibiotics are useful only

against specific bacteria

- to finish the entire course of the

medication

- to increase oral fluids


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Evaluate

- therapeutic effect

- adverse effect

- patients understanding of the

medication regimen


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AMINOGLYCOSIDES

CIN

AMIKACIN

GENTAMYCIN

STREPTOMYCIN

NEOMYCIN- decreased ammonia

forming bacteria in the G.I. tract of

a patient in hepatic coma


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2. Cephalosporins similar to penicillins in

structure and activity

- Overtime, 4 generations ofCephalosporins have been introduced,

each group with its own spectrum of

activity> First generation

> second generation

> Third generation

> Fourth generation


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Mechanism of Action:

> Inhibits bacterial wall synthesis

> Most effective against rapidly growing

organism


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INDICATIONS

- Gram (-) & gram (+) organisms

SPECIAL PRECAUTIONS

> Hypersensitivity

> Renal or hepatic disorders


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UNDESIRABLE EFFECTS

G.I., nausea & vomiting, diarrhea

Increased glucose

Anaphylaxis may occur; alcohol may cause

vomiting

Nephrotoxocity

Thrombocytopenia


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- MEDICATE

- Taken on empty stomach

EVALUATON

- (-) cultures

- Normal WBC & body temperature


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CEPHALOSPHORINS

CEF

CEFAZOLIN (ANCEF)

CEFACLOR (CECLOR)

CEFTRIAXONE (ZINACEF)


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3. Flouroquinolone


> Bactericidal> Inhibits bacterial DNA synthesis


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INDICATIONS

Broad spectrum

> LRTI

> STDs

> UTI

> Eye infection

> Gram (-) & gram (+)

> Skin infection


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SPECIAL PRECAUTIONS

> Hypersensitivity

UNDESIRABLE EFFECTS

> Nausea & vomiting, diarrhea

> Photosensitivity

> Headache> Dizziness



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- MEDICATE

- Slowly infuse Ofloxacin & Ciprofloxacin

- Take 2 hours before or 2 hours after

antacids or other iron

- Avoid Theophylline, Anticoagulant,

Digoxin

EVALUATION> (-) cultures

> Normal temperature & WBC


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FLOUROQUINOLONESFLOXACIN

CIPROFLOXACIN (CIPROBAY)

OFLOXACIN

LEVOFLOXACIN


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4. MACROLIDES


> Bacteriostatic

> Inhibits synthesis of protein in

bacteria

INDICATIONS> Client who are allergic to

penicillins

SPECIAL PRECAUTIONS> Lactation

> Hepatic dysfunction

UNDESIRABLE EFFECTS


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UNDESIRABLE EFFECTS

> Tinnitus, anorexia, nausea & vomiting,

diarrhea


* Take 1 hour before or 2 hours after meals(empty stomach)

* Take with full glass of water and NOT

FRUIT JUICE - decreased activity if takenwith acidic drinks


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EVALUATION

> (-) cultures

> Normal WBC & temperature


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Macrolides

Erythromycin (ERYTHROCIN)

Azithromycin (ZITHROMAX)


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5. Penicillins

Sir Alexander Fleming in 1920discovered penicillin from molds


> Bactericidal

> Inhibits the enzyme in the cell wall ssynthesis


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INDICATIONS

> Most gram (+) & gram (), cocci & bacilli

> Pneumonia, UTI, respiratory infection,

syphilis, gonorrhea, meningitis

SPECIAL PRECAUTIONS

> Hypersensitivity to Penicillins or

Cephalospori's


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UNDESIRABLE EFFECTS

> Rash, nausea & vomiting

> Stomatitis & super infectionsNURSING RESPONSIBILITIES

> Taken on empty stomach

EVALUATION

> Normal temperature & WBC


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PENICILLINS

CILLIN

AMOXICILLIN (AMOXIL)

PIPERACILLIN

PEN G. BENZATHINE

OXACILLIN

6. SULFONAMIDES


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Mechanism of Action

> Bacteriostatic> Interferes with bacterial growth by

blockingfolicacidsynthesis in the cell

INDICATIONS

> Respiratory infection

> UTI> PCP

> Pneumonia


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SPECIAL PRECAUTIONS

> Elderly

> Renal/hepatic disease

UNDESIRABLE EFFECTS

> Renal toxicity

> Acute hemolytic anemia

> Steven-Johnson's Syndrome


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> Report sore throat & easy bruising> Taken on empty stomach

> Take with 1 glass of water

> If nausea & vomiting occurs, administerwith food

> Avoid direct exposure to sunlight

EVALUATION> Normal temperature & WBC


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SULFONAMIDES

SULFADIAZINE

COTRIMOXAZOLE (BACTRIM)


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7. Tetracyclines


> Bacteriostatic

> Inhibits protein synthesis bybinding to ribosome


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INDICATIONS

> Leptospirosis

> Lyme's disease> Rocky mountain fever

> Cholera

> Skin infections


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SPECIAL PRECAUTIONS

> Pregnancy/lactation

> Children below 8 years old due to

permanent staining of the teeth

UNDESIRABLE EFFECTS> Photosensitivity

> Nephrotoxocity

> Tooth staining


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> Store the meds out of light & heat

> Take on empty stomach

> Take with a full glass of water

> Avoid antacids, iron

EVALUATION> Normal temp. & WBC


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TETRACYCLINES

CYCLINE

DOXYCYCLINE

MINOCYCLINE

TETRACYCLINE


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8. ANTITUBERCULARS

a. Isoniazid

Mechanism of Action

> Interferes with DNA synthesis

INDICATIONS

> PTB; prophylactic for TB


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SPECIAL PRECAUTIONS

> Alcoholism, renal disease

> Diabetic retinopathy

> Pregnancy

UNDESIRABLE EFFECTS

> Peripheral neuropathy


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> Empty stomach

> Administer Vitamin B6

EVALUATION> Normal temp, & WBC


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b. Rifampicin


> Interferes with RNA synthesis

INDICATIONS

> PTB in combination with

other anti TB


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SPECIAL PRECAUTIONS

> Alcoholism, renal disease

> Diabetic retinopathy

> Pregnancy


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UNDESIRABLE EFFECTS

> Body fluid discoloration (reddishorange urine & sputum)


> Empty stomach

EVALUATION> Normal temp. & WBC


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Chapter 3

Antifungals

I. ANTIFUNGAL

ZOLE


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FLUCONAZOLE (DIFLUCAN)

KETOCONAZOLE (NIZORAL)

ACTIONS

> Increases permeability of the fungal cell wall causing

cell death

INDICATIONS

> Fungal infections

> CandidiasisSPECIAL PRECAUTIONS

> Hypersensitivity

> Liver failure

> Pregnancy> Lactation

UNDESIRABLE EFFECTS


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UNDESIRABLE EFFECTS

> Headache, dizziness, nausea & vomiting


> Take with food

> Liver function test monthly

EVALUATION

> (-) fungal infection

J. ANTIPROTOZOAL

PENTAMIDE ISOTHIONATE (NEBUPENT)


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ACTIONS

> Inhibits DNA synthesis

INDICATIONS

> Treatment & prevention of PCP

SPECIAL PRECAUTIONS

> Hypersensitivity

.UNDESIRABLE EFFECTS

> Orthostatic hypotension


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> Orthostatic hypotension


> Check BP

> Change position slowly

> Monitor blood test & blood sugar level

EVALUATION

> (-) infection

AMOEBICIDE


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METRONIDAZOLE(FLAGYL)

ACTIONS

Amoebicidal

> Inhibits DNA synthesis causing cell death

INDICATIONS

> Amoebiasis> Trichomoniasis

> Gardnerella Vaginalis

SPECIAL PRECAUTIONS

> Blood dyscrasias

> Hepatic disease


UNDESIRABLE EFFECTS


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> Turns urine to brown

> Disulfiram-like interaction with alcohol

> Flushing

> Nausea

> Tachycardia

> Teratogenic


> Monitor CBC & liver function test

> Take with food

> No alcoholduring therapy & at least 48 hours afterEVALUATION

(-) parasite (amoeba)

K. ANTIVIRAL


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VIR

ACYCLOVIR (ZOVIRAX)

ACTIONS

> Interferes with DNA synthesis & replication of virus

> Virustatic

INDICATIONS

> Herpes simplex 1

> Genital herpes 11

> Chicken pox

SPECIAL PRECAUTIONS

/l i


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> Renal/hepatic disease

UNDESIRABLE EFFECTS

> Nephrotoxicity

> Neuropathy

> Bone marrow depression


> Avoid intercourse during treatment

> Monitor BP

> Never give IV bolus

* Does not cure herpes, only shorten the


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episode

> Pap smear due to increased risk of cervicalcancer

EVALUATION> Decreased signs & symptoms of viral

infection

AZT


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AZT

ACTIONS

> Increased CD4 cells

INDICATIONS> HIV

A/E:

Bone Marrow Depression

ANTINEOPLASTIC AGENTS


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A. ALKYLATING AGENTS

CYCLOPHOSPHAMIDE (CYTOXAN)

NITROGEN MUSTARD

ACTIONS

> Causes cell death or mutation of malignant cells* Action must evident in rapidly dividing cells

INDICATIONS

> Chronic lymphocytic leukemia> Hodgkin disease

> Malignantlymphoma

SPECIAL PRECAUTIONS


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> Hypersensitivity


> Active infection

> Recent immunization

UNDESIRABLE EFFECTS

> Nausea & vomiting

> Alopecia


> Hemorrhagic cystitis (Cytoxan)-give the drug in the

morning



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CBC, platelet-monitor

AntiemeticNephrotoxicity (U/E)

Counseling

Encourage hand washing, avoid crowdsReverse isolation

recommend a wig or cap for alopecia

EVALUATION> Decreased in tumor size

(-) signs & symptoms of bone marrow & S/E

B. ANTIMETABOLITES


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CYTARABINE

FLOROURACIL (5-FU)

METHOTREXATE (MTX)

ACTIONS

> Interferes with the building blocks of DNAsynthesis

* Greatest activity is in the S phase of the cell cycle

INDICATIONS

> ALL> Non-Hodgkin

> Cervix, colon, ovary, liver, pancreas, etc..


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SPECIAL PRECAUTIONS

> refer to Alkylating agents

UNDESIRABLE EFFECTS

> refer to Alkylating agents


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Chapter 3

Antiviral Agents

Viruses


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- to carry on any metabolic processes &

replication, a virus must enter a host cell- the viruses replicate in the host cell

- when the host cell can no longer carry

out its own function because of theinvading virus, the host cell dies and

releases new viruses into the body to

invade other cells


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- Interferons are released by the host inresponse to viral invasion of a cell and

prevent the replication of that particular

virus


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Classes of Antiviral Agents

1. Agents for Influenza A & Respiratoryviruses

2. Agents for Herpes and Cytomegalovirus

3. Agents for HIV and AIDS

4. Locally Active Antiviral Agents


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Chapter 3

Antifungal Agents


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Mycosis an infection caused by a fungus

Who are susceptible for fungal infections?

- patients with AIDS

- patients with AIDS-related complex (ARC)- those taking immunosuppressant drugs

- those who underwent transplantation

surgery, cancer treatment- elderly

S t i A tif l


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Systemic Antifungals

- toxic to the host

- get a culture of the fungus to ensure rightantifungal is given

Topical Antifungals

- used to treat mycoses of the skin and

mucous membrane ex: tinea infections

- too toxic for systemic administration, care

should be taken when there is open ordraining wounds


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Classes of Antifungals

1. Systemic Antifungals- Amphotericin B

- Fluconazole

- Flucytosine- Itraconazole

- Nystatin


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2. Topical Antifungals

- Amphotericin B

- Gentian Violet

- Butenafine

- Butoconazole

- Ciclopirox

- Clotrimazole

- econazole

- Haloprogin

- Miconazole


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