1 © paradigm publishing, inc. chapter 4 antibiotics

1© Paradigm Publishing, Inc.

Chapter 4

Antibiotics

© Paradigm Publishing, Inc. 2

Learning Objectives

• Identify the major types of antibiotics by drug class.

• Know which auxiliary labels to use when dispensing major types of antibiotics.

• Define therapeutic effects side effects, and administration routes of major antibiotics.

• Use antibiotic and general drug terminology correctly in written and oral communication.


Fighting Bacterial Infections

• Bacteria– Single-celled organisms occurring in

most environments

• Infection– Condition in which bacteria grow in body

tissues and cause tissue damage by their presence or by toxins they produce


Types of Bacteria

• Aerobic– Needs oxygen to survive

• Anaerobic– Survives in the absence of oxygen


Bacteria Shapes

(a) Round cocci

(b) Rod-like bacilli

(c) Spiral-shaped spirochetes


Gram Stain

(a) Gram-positive bacteria turn purple

(b) Gram-negative bacteria appear red


Gram Stain Results and Related Diseases

Shape Gram Stain Bacteria Related Disease

rods gram-positive

Corynebacteria endocarditis

rods gram-negative

E. Coli UTI



Shape Gram Stain Bacteria Related Disease

cocci gram-positive

Staphylococcus toxic shock syndrome

cocci gram-negative

Neisseria gonorrhea



Shape Gram Stain

Bacteria Related Disease

curved or spiral rods

gram-negative

Campylobacter septicemia

spirochetes gram-negative

Treponema palladium

syphilis


How Antibiotics Work

• Prevent folic acid synthesis– Sulfonamides

• Inhibit cell wall formation– Penicillins– Cephalosporins


How Antibiotics Work• Prevent folic acid synthesis• Inhibit cell wall formation

• Block protein formation– Macrolides

– Tetracyclines

– Aminoglycosides

• Interfere with DNA formation


How Antibiotics Work• Prevent folic acid synthesis• Inhibit cell wall formation• Block protein formation• Interfere with DNA formation

• Disrupt cell membranes– Cyclic lipopeptides

• Disrupt DNA structure– Metronidazole


Dispensing Issues of Antibiotics

• Mix exactly as directed by manufacturer

• Swab counting tray with alcohol between drugs to prevent cross-contamination

Warning!


Side Effects of Antibiotics

• Most antibiotics taken on an empty stomach to attain faster absorption

• Exceptions– nitrofurantoin (Macrobid, Macrodantin)– cefuroxime (Ceftin, Zinacef)


Antimicrobial Resistance

• Developing largely because of

– Overuse

– Misuse

• Superinfection may occur


Antimicrobial Resistance

• Pharmacy technician—place a label on antibiotics advising patient to take all of the medication


Terms to Remember

bacteria

infection

aerobic

anaerobic

Gram staining


Terms to Remember

bactericidal agent

bacteriostatic agent

superinfection

Major classes of antibiotic drugs

• Sulfonamides

• Pencillins

• Cephalosporins

• Tetracyclines and Tigecycline

• Macrolides

• Ketolides

• Quinolones

• Streptogramins

• Aminoglycosides

• Cyclic Lipopetides



Sulfonamides

• AKA “sulfa drugs”

• Effective against a broad range of microorganisms

• Block specific step in biosynthetic pathway of folic acid

• Interfere with PABA and folic acid formation, thereby destroying bacteria


Drug ListSulfonamides

– sulfamethoxazole-trimethoprim (Bactrim, Bactrim DS, Cotrim, Cotrim DS, Septra, Septra DS)

– sulfasalazine (Azulfidine)

– sulfisoxazole (Gantrisin)

– Related drug: nitrofurantoin (Macrobid, Macrodantin)


Allergy to Sulfonamides

• If patient is allergic to sulfa, then drug of choice is nitrofurantoin (Macrobid, Macrodantin)


Therapeutic Uses of Sulfonamides

• Urinary tract infections (UTIs)

• Otitis media

• Ulcerative colitis

• Lower respiratory infections

• Prophylaxis in Pneumocystis carinii pneumonia in immunocompromised


Side Effects of Sulfonamides

• Rash

• Nausea

• Drug fever

• Vomiting

• Jaundice

• Kidney damage

• Blood complications


Dispensing Issues of Sulfonamides

• Avoid sun

• Maintain adequate fluid intake


Penicillins

• Low toxicity• Derivatives created by manipulating basic

molecular structure of drug

• Kills bacteria by preventing them from forming rigid cell wall

• Because human cells do not have rigid cell walls, they are not affected


Drug ListPenicillin Drugs

– amoxicillin (Amoxil)

– ampicillin (Principen)– penicillin G (various brand names,

also different salts, i.e. potassium, sodium)

– penicillin V (Veetids)


Drug ListResistant Penicillins

Penicillinase-Resistant Penicillins– dicloxacillin (Dycil)

– nafcillin (Unipen)– oxacillin (none)


Drug ListResistant Penicillins

Extended-Spectrum Penicillins– carbenicillin (Geocillin)

– piperacillin (none)

– ticarcillin (Ticar)


Drug List

Resistant Penicillins

Penicillin Combinations– amoxicillin-clavulanate

(Augmentin)

– ampicillin-sulbactam (Unasyn)

– piperacillin-tazobactam (Zosyn)

– ticarcillin-clavulanate (Timentin)


Therapeutic Uses of Penicillins

• Abscesses

• Beta-hemolytic streptococcus

• Meningitis

• Otitis media

• Pneumonia


Therapeutic Uses of Penicillins

• Respiratory infections

• Strep throat

• Tooth and gum infections

• Sexually transmitted diseases (STDs; syphilis and gonorrhea)

• Endocarditis due to streptococci


Side Effects of Penicillins

• Diarrhea

• Allergies in 7% to 10% of population


Dispensing Issues of Penicillins

• Take on an empty stomach – Food slows absorption

– Acids in fruit juices or colas could deactivate drug


Resistance to Penicillins

• Penicillinase-resistant penicillins work against gram-positive aerobes

• Extended-spectrum penicillins are more resistant to gram-negative bacteria

• Penicillin combinations improve effect


Cephalosporins

• Mechanism of action similar to penicillins

• Person allergic to penicillin has about 1% chance of being allergic to cephalosporins


Drug ListFirst-Generation Cephalosporins

– cefadroxil (Duricef)

– cefazolin (Ancef)

– cephalexin (Keflex)


Drug ListSecond-Generation Cephalosporins

– cefaclor (Ceclor)

– cefprozil (Cefzil)

– cefuroxime (Ceftin, Zinacef)


Drug ListThird-Generation Cephalosporins

– cefdinir (Omnicef)

– cefditoren (Spectracef)

– cefixime (Suprax)

– cefotaxime (Claforan)

– cefpodoxime (Vantin)


Drug ListThird-Generation Cephalosporins

– ceftazidime (Fortaz)

– ceftibuten (Cedax)

– ceftizoxime (Cefizox)

– ceftriaxone (Rocephin)


Drug List

Fourth-Generation Cephalosporins– cefepime (Maxipime)


Dispensing Issues of Cephalosporins

• Alert pharmacist if patient who is allergic to penicillin is receiving a cephalosporin Rx

• If patient wants cephalosporin dispensed, document communication in case of cross-reaction

Warning!


First-Generation Cephalosporins

• Similar to penicillinase-resistant penicillins but have greater gram-negative coverage

• Used for – Community-acquired infections– Mild to moderate infections


Second-Generation Cephalosporins

• Increased activity, especially against Haemophilus influenzae

• Used for – Otitis media in children– Respiratory infections– Urinary tract infections (UTIs)


Third-Generation Cephalosporins

• Active against wide spectrum of gram-negative organisms

• Long half-life, so once-a-day dosing for some

• Used for– Ambulatory patients– Children (dosing before or after school)


Fourth-Generation Cephalosporins

• Broad-spectrum coverage, such as cefepime (Maxipime)

• Used for– Pneumonia– UTIs– Sepsis

• IV form mixed in NS or D5W


Side Effects of Cephalosporins

• Share side effects of penicillin

• A few may initiate unique toxic reactions

• Lower frequency of toxicity than many other antibiotics


Dispensing Issues of Cephalosporins

• All cephalosporins look alike when written in the generic form

• Watch dosing and indications for use

Warning!


Drugs Related to Penicillins and Cephalosporins

• New beta-lactam drugs differ slightly in structure

• Carabpenems, carbacephems, and monobactam

• Some used for serious infections


Drug ListCarbapenems

– ertapenem (Invanz)

– imipenem-cilastatin (Primaxin)

– meropenem (Merrem I.V.)


Drug List

Carbacephem– doripenem (Doribax)

– loracarbef (Lorabid)

Monobactam– aztreonam (Azactam)


Tetracyclines

• Broad-spectrum bacteriostatic antibiotics

• Inhibit protein synthesis in bacteria by binding to ribosomes

• Suppress infection, but require phagocytes to eradicate bacteria completely


Drug ListTetracyclines

– demeclocycline (Declomycin)

– doxycycline (Vibramycin, Oracea, Adoxa)

– minocycline (Minocin, Soladyne)

– tetracycline (Sumycin)


Therapeutic Uses of Tetracyclines

• Acne• Anthrax• Chronic bronchitis• Lyme disease• Mycoplasma pneumoniae infection• Rickettsia infection• Some sexually transmitted diseases, such

as Chlamydia infection


Side Effects of Tetracyclines

• Gastrointestinal upset with nausea and vomiting


Dispensing Issues of Tetracyclines

• Avoid antacids to avoid chelation with minerals

• Photosensitization

• Pregnant women and children up to age 9 must avoid



• Expired drugs can be toxic, can cause fatal renal syndrome

• Pharmacy technician always watch the expiration date

Warning!



• Government agencies stockpiling tetracyclines due to concern over terrorist attack

• Due to toxicity: must be rotated; destroy when out of date

Warning!


Tigecycline

• New drug class: glycylcycline

• Similar to tetracyclines

• Used for– Skin infections– Intra-abdominal infections


Drug ListTigecycline

– tigecycline (Tygacil)


Macrolides

• Inhibit protein synthesis by combining with ribosomes

• Used primarily to treat pulmonary infections


Drug ListMacrolides

– azithromycin (Zithromax, Z Pak, Zmax)

– clarithromycin (Biaxin)

– dirithromycin (Dynabac)

– erythromycin base (Eryc, Ery-Tab)


Drug ListMacrolides

– erythromycin ethylsuccinate (E.E.S., EryPed)

– erythromycin lactobionate (Erythrocin)

– erythromycin stearate (Erythrocin)

– erythromycin-sulfisoxazole (Pediazole)


Therapeutic Uses of Macrolides

Drugs of choice for– Chlamydia– Group A beta-hemolytic streptococcus– H. influenzae– Legionnaires’ disease– M. pneumoniae– S. pneumoniae


Dispensing Issues of Macrolides

• Most antibiotics taken on empty stomach

• Some forms of erythromycin can cause severe GI distress and should be taken with food


Dispensing Issues of Macrolides

• Can be misread– erythromycin– azithromycin

• Dosing should help identify drug

Warning!


Ketolides

• Bind to ribosomal subunits and block protein synthesis

• May inhibit newly forming ribosomes

• Bacteria resistant to macrolides, lincomycin derivatives, and streptogramins is also resistant to ketolides

• Used to treat bacterial infections in lungs and sinuses


Drug ListKetolides

– telithromycin (Ketek)


Quinolones

• Strong, rapid bactericidal action against– Most gram-negative bacteria– Many gram-positive bacteria

• Antagonize enzyme responsible for coiling and replicating DNA, causing DNA breakage and cell death


Drug ListQuinolones

– ciprofloxacin (Cipro)

– gatifloxacin (Tequin)

– gemifloxacin (Factive)

– levofloxacin (Levaquin)

– moxifloxacin (Avelox)

– norfloxacin (Noroxin)

– ofloxacin (Floxin)


Therapeutic Uses of Quinolones

• Bone and joint infections caused by gram-negative organisms

• Infectious diarrhea• Ophthalmic infections• Some sexually transmitted diseases• Upper respiratory infections• Urinary tract infections (UTIs)


Side Effects of Quinolones

• Primarily gastrointestinal, with nausea and vomiting

• Some joint swelling, dizziness, and unpleasant taste

• Can cause joint problems and malformations

• Patients have tendency to injure tendons


Dispensing Issues of Quinolones

• Not to be given with theophylline

• Antacids interfere with absorption

• Avoid sun


Streptogramins

• Inhibit protein synthesis within the bacterial ribosomes

• Alternative to vancomycin

• Side effects similar to quinolones: nausea, vomiting, joint swelling, dizziness


Drug ListStreptogramins

– quinupristin-dalfopristin (Synercid)


Aminoglycosides

• Used to treat serious infections

• Inhibits bacterial protein synthesis by binding to ribosomal subunits

• After first dose, dosage adjusted according to plasma concentrations


Drug ListAminoglycosides

– amikacin (Amikin)– gentamicin (Garamycin)– kanamycin (Kantrex)– neomycin (Mycifradin, Neo-Fradin,

Neo Rx)– streptomycin (none)– tobramycin (Nebcin)


Side Effects of Aminoglycosides

• Nephrotoxicity (destructive to kidney)

• Ototoxicity (damage organs of hearing)– Equilibrium problems – Tinnitus– Permanent deafness

• Neuromuscular blockade


Dosing of Aminoglycosides

• Dosed 1x/daily instead of 2 to 3x/daily

• Less frequent dosing may reduce toxicity– Less drug accumulates in kidneys and ears

– Simplifies drug monitoring

• Trough levels should be checked before second dose to confirm drug elimination


Cyclic Lipopetides

• Bind bacterial membranes causing cell membrane to depolarize

• Leads to– Inhibition of DNA and RNA synthesis– Bacterial death


Drug List

Cyclic Lipopetides– daptomycin (Cubicin)

• Do not take with statins

Warning!


Terms to Remember

sulfonamides

penicillin

cephalosporin

community-acquired

NS

D5W


Terms to Remember

tetracycline

chelation

macrolide

ketolide

quinolone

streptogramin


Terms to Remember

aminoglycoside

sepsis

nephrotoxicity

ototoxicity

cyclic lipopeptide

hypotension


Other Antibiotics

• Five important antibiotics are structurally distinct from– Those in other classes– Each other


Drug ListAntibiotics Independent of Class

– clindamycin (Cleocin)

– linezolid (Zyvox)

– metronidazole (Flagyl)

– pentamidine (NebuPent, Pentam)

– vancomycin (Vancocin)


vancomycin (Vancocin)

• Bacterial resistance increasing due to overuse

• Strict CDC guidelines for handling and use

Warning!


clindamycin (Cleocin)

• Broad-spectrum antibiotic used for– Acne– Penicillin alternative in dental

prophylaxis– Anaerobic pneumonia– Bone and bowel infections– Female genital and intra-abdominal

infections


clindamycin (Cleocin)

• If patient develops diarrhea, drug must be discontinued

Warning!


linezolid (Zyvox)

• First oxazolidinone approved by FDA

• Inhibits bacterial protein synthesis

• Drug must be protected from light


metronidazole (Flagyl)

• Pharmacy technician—place No Alcohol warning sticker on medication


pentamidine (NebuPent, Pentam)

• Second-line agent for Pneumocystis carinii

• Mechanism of action unknown

• Patient may develop sudden hypotension (low blood pressure)


Storage of Liquid Antibiotics

• After lyophilized (powdered) antibiotics are mixed– Some need refrigeration– Others stored at room temperature

• Pharmacy technician may tell storage information to patient


Ophthalmic Antibiotics

• Some antibiotics have ophthalmic (eye) dosage forms

• Very few antibiotics have otic forms– Very painful in the eye– Otic medicines have different pH than

the eye


Drug ListOphthalmic Dosage Forms

– azithromycin (AzaSite)

– bacitracin (AKtracin)

– ciprofloxacin (Occuflox, Ciprodex)

– erthromycin (Ilotycin)

– gatifloxacin (Zymar)


Drug ListOphthalmic Dosage Forms

– gentamicin (Gentak, Genoptic)

– moxifloxacin (Vigamox)

– oxfloxacin (Ocuflox)

– sodium sulfacetamide (Bleph 10)

– tobramycin (Tobrex)


Dispensing Issues of Ophthalmic Antibiotics

• Newer eye drops very expensive, often rejected by insurance companies

• Pharmacy technician will need to let prescriber know– What eye drops are available– Which ones insurance most likely cover


Terms to Remember

ophthalmicto be used in the eye

otic to be used in the ear

pHa measurement of acidity or alkalinity; pH 7 neutral


Treating Complications of Infections

• drotrecogin alfa (Xigris)– Not an antibiotic

– Used in treating some complications of sepsis (life-threatening result of serious infections)

– Anticoagulant and anti-inflammatory

– High cost, strict guidelines limit use


Drug ListAdjunct in Treating Sepsis

– drotrecogin alfa (Xigris)


Assignments

• Complete Chapter Review activities• Answer questions in Study Notes

document• Study Partner

– Quiz in review mode– Matching activities– Drug tables

1 © paradigm publishing, inc. chapter 4 antibiotics

Documents

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effects of antibiotics

major types of antibiotics

gram stain results

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