Chapter04 Antibiotics

Chapter 4

Antibiotics

BY :SANJAY RAJPUROHIT

Chapter 4 Topics

• Bacteria• How Antibiotics Work• Classes of Antibiotics

• Antibiotics Independent of Classes• Adjunct in Treating Sepsis• Discussion Questions

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 communications.

Fighting Bacterial Infections

• Bacteria: microorganisms that cause infection

• Bactericidal agent: kills the invading organism

• Bacteriostatic agent: inhibits the growth or multiplication of bacteria

Types of Bacteria

• Aerobic bacteria

• Anaerobic bacteria

Types of Bacteria

• Aerobic bacteria needs oxygen to survive

• Anaerobic bacteriasurvives in the absence of oxygen

Bacteria Shapes

(a) Round cocci

(b) Rod-like bacilli

(c) Spiral-shaped spirochetes

Gram’s Stain Results and Related Diseases

Shape Gram’s Stain

Bacteria Related Disease

rods gram-positive Corynebacteria endocarditis

gram-negative E. Coli UTI


Shape Gram’s Stain Bacteria Related Disease

cocci gram-positive Staphylococcus toxic shock syndrome

gram-negative Neisseria gonorrhea


Shape Gram’s Stain Bacteria Related Disease

curved or spiral rods

gram-negative Campylobacter septicemia

spirochetes gram-negative Treponema palladium

syphilis

How Antibiotics Work

• Block protein formation


• Block protein formation– Macrolides– Tetracyclines– Aminoglycosides



• Inhibit cell wall formation



• Inhibit cell wall formation– Penicillins– Cephalosporins




• Interfere with DNA formation




• Interfere with DNA formation– Nalidixic acid





• Prevent folic acid synthesis





• Prevent folic acid synthesis– Sulfonamides

Antibiotic Dispensing Issues

• Mix exactly as directed by manufacturer

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

Warning!

Antibiotic Side Effects

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

Antibiotic Side Effects

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

• Examples of exceptions– nitrofurantoin (Macrobid, Macrodantin)– cefuroxime (Ceftin, Zinacef)

Antimicrobial Resistance

• Developing largely because of

–overuse

–misuse

Antimicrobial Resistance

• Developing largely because of – overuse – misuse

• The Pharmacy Technician’s role– Place an label on antibiotics advising the

patient to take all of the medication

Discussion

How might the widespread use of antibacterial soaps affect the population?

Classes of Antibiotics

• Sulfonamides

• Penicillins

• Cephalosporins

• Tetracyclines

• 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

Sulfonamides and Related Drugs

• nitrofurantoin (Macrobid, Macrodantin)

• sulfamethoxazole-trimethoprim (Bactrim DS, Septra DS)

• sulfisoxazole (Gantrisin)

Drug List

Sulfonamides

• If patient is allergic to sulfa….

Sulfonamides

• If patient is allergic to sulfa….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 patients

Sulfonamides’ Side Effects

• Rash

• Nausea

• Drug fever

• Vomiting

• Jaundice

• Blood complications

• Kidney damage

Sulfonamides’ Dispensing Issues

• Avoid the sun

• Maintain adequate fluid intake

Penicillins

• Low toxicity• Effective derivatives created from

manipulating drug’s basic molecular structure

• Kills bacteria by preventing them from forming the rigid cell wall

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

Penicillins

• amoxicillin (Amoxil, Trimox)

• amoxicillin-clavulanate (Augmentin)

• ampicillin (Principen)

• ampicillin-sulbactam (Unasyn)

• carbenicillin (Geocillin)

Drug List

• dicloxacillin

• nafcillin

• oxacillin

• penicillin G (various)

• penicillin V (Veetids)

• piperacillin

Penicillins

Drug List

• piperacillin-tazobactam (Zosyn)

• ticarcillin (Ticar)

• ticarcillin-clavulanate (Timentin)

Penicillins

Drug List

Therapeutic Uses of Penicillins

• Abscesses• Beta-hemolytic streptococcus• Meningitis• Otitis media• Pneumonia• Respiratory infections• Tooth and gum infections• Venereal diseases (syphilis and gonorrhea)• Endocarditis due to streptococci

Penicillins’ Side Effects

• Diarrhea

• Allergies in 7% to 10% of population

Penicillins’ Dispensing Issues

• Take on an empty stomach– Food slows absorption

– Acids in fruit juices or colas could deactivate the drug

Penicillin Resistance

• Penicillinase-resistant penicillins work against gram-positive aerobes

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

• Penicillin combinations improve effect

Cephalosporins

• Have a mechanism of action similar to penicillins

• A person allergic to penicillin, about 10% chance of being allergic

Cephalosporins

Alert the Pharmacist if a patient allergic to penicillins is receiving a cephalosporin prescription.

Warning!

Cephalosporins

• First-generation

Cephalosporins

• First-generation– Similar to penicillinase-resistant penicillins

with greater gram-negative coverage

– Used for • community-acquired infections• mild to moderate infections

Cephalosporins

• Second-generation

Cephalosporins

• Second-generation– Increased activity, especially against

Haemophilus influenzae

– Used for • Otitis media in children• Respiratory infections• UTIs

Cephalosporins

• Third-generation

Cephalosporins

• Third-generation– Active against a 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)

Cephalosporins Side Effects

• Share side effects of penicillin

• Few may initiate unique toxic reactions

• Lower frequency of toxicity than many other antibiotics

Cephalosporins

All of the cephalosporins look alike when written in the generic form. Watch for dosing and indications for use.

Warning!

• cefaclor (Ceclor)

• cefadroxil (Duricef)

• cefazolin (Ancef)

• cefdinir (Omnicef)

• cefditoren (Spectracef)

• cefepime (Maxipime)

Cephalosporins

Drug List

• cefotaxime (Claforan)

• cefotetan (Cefotan)

• cefoxitin (Mefoxin)

• cefpodoxime (Vantin)

• cefprozil (Cefzil)

• ceftazidime (Fortaz)

• ceftibuten (Cedax)

Cephalosporins

Drug List

• ceftizoxime (Cefizox)

• ceftriaxone (Rocephin)

• cefuroxime (Ceftin, Zinacef)

• cephalexin (Keflex)

• cephradine (Velosef)

Cephalosporins

Drug List

Tetracyclines

• Broad-spectrum bacteriostatic antibiotics

• Inhibit protein synthesis in bacteria by binding to ribosomes

• Suppress the infection and require phagocytes to complete the eradication of the bacteria

Therapeutic Uses of Tetracyclines

• Acne• Chronic bronchitis• Lyme disease• Mycoplasma pneumoniae infection• Rickettsia infection• Some venereal diseases, such as Chlamydia

infection• Traveler’s diarrhea

Tetracyclines’ Side Effects

• Gastrointestinal upset with nausea and vomiting

Tetracyclines’ Dispensing Issues

• Avoid antacids to avoid chelation with minerals

• Photosensitization

• To be avoided by pregnant women and children

• Expired drugs are dangerous

• demeclocycline (Declomycin)

• doxycycline (Vibramycin)

• minocycline (Minocin)

• tetracycline (Sumycin)

Tetracyclines

Drug List

Macrolides

• Inhibit protein synthesis by combining with ribosomes

• Used primarily to treat pulmonary infections

Macrolides

Drugs of choice for the following illnesses and specific bacteria:

– Chlamydia– Group A beta-hemolytic streptococcus– H. influenzae– Legionnaire’s disease– M. pneumoniae– S. pneumoniae

Macrolides’ Dispensing Issues

Although most antibiotics should be taken on an empty stomach, erythromycins usually cause severe GI distress, so should be taken with food

Macrolides

Erythromycin and azithromycin can be misread, but the dosing should help.

Warning!

• azithromycin (Zithromax, Z-PAK)• clarithromycin (Biaxin)• dirithromycin (Dynabac)• erythromycin base (Eryc, Ery-Tab)• erythromycin ethylsuccinate (E.E.S., EryPed)• erythromycin lactobionate (Erythrocin) • erythromycin stearate (Erythrocin)• erythromycin-sulfisoxazole (Pediazole)

Macrolides

Drug List

Ketolides

• Block protein synthesis by binding to ribosomal subunits

• May inhibit the formation of newly forming ribosomes

• Bacteria resistant to macrolides, lincomycin derivatives, and streptogramins are also resistant

• Used to treat bacterial infections in the lungs and sinuses

• telithromycin (Ketek)

Ketolides

Drug List

Quinolones

• Strong, rapid bactericidal action against most gram-negative and many gram-positive bacteria

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

Therapeutic Uses of Quinolones

• Bone and joint infections caused by gram-negative organisms

• Infectious diarrhea

• Ophthalmic infections

• Some sexually transmitted diseases

• Upper respiratory infections

• UTIs

Quinolones’ Side Effects

• Primarily gastrointestinal, with nausea and vomiting

• Dizziness• Unpleasant taste• Can cause joint problems such as swelling

and malformations• Patients taking them have a tendency to

injure tendons

Quinolones’ Dispensing Issues

• Not to be given with theophylline

• Antacids interfere with absorption

• Avoid exposure to sun

• ciprofloxacin (Ciloxan, Cipro)

• gatifloxacin (Tequin)

• gemifloxacin (Factive)

• levofloxacin (Levaquin)

• moxifloxacin (Avelox, Vigamox)

• norfloxacin (Noroxin)

• ofloxacin (Floxin, Ocuflox)

Quinolones

Drug List

Streptogramins

• Inhibit protein synthesis within the bacterial ribosomes

• Alternative to vancomycin

• Side effects similar to quinolonesnausea and vomitingjoint swellingdizziness

• quinupristin-dalfopristin (Synercid)

Streptogramins

Drug List

Aminoglycosides

• Treat serious infections

• Inhibits bacterial protein synthesis by binding to ribosomal subunits

Aminoglycosides’ Side Effects

• Nephrotoxicity, destructive to kidney

• Ototoxicity– Tinnitus– Permanent deafness– Equilibrium problems

• Neuromuscular blockade

Aminoglycosides

• Less frequent dosing may help reduce toxicity– Less drug accumulates in the kidney and ear

– Simplified drug monitoring

• Levels should be checked prior to administration of second dose to confirm drug elimination

• amikacin

• gentamicin (Garamycin, Genoptic)

• kanamycin (Kantrex)

• neomycin (Myciguent, Neo-Fradin)

• streptomycin (none)

• tobramycin (Nebcin)

Aminoglycosides

Drug List

Cyclic Lipopetides

• Bind bacterial membranes and cause the cell membrane to depolarize

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

• daptomycin (Cubicin)

Do not take with statins.

Warning!

Cyclic Lipopetides

Drug List

Antibiotics Independent of Classes

These antibiotics are independent of other classes and each other due to structural differences.

• chloramphenicol (Chloromycetin)

• clindamycin (Cleocin)

• linezolid (Zyvox)

• metronidazole (Flagyl)

• pentamidine (NebuPent, Pentam)

• vancomycin (Vancocin)


Drug List


vancomycin (Vancocin)

Bacterial resistance is increasing due to overuse.

Warning!


Uses of clindamycin (Cleocin) – Acne– Alternative to penicillin in dental prophylaxis– Anaerobic pneumonia– Bone infections– Bowel infections– Female genital infections– Intra-abdominal infections


clindamycin (Cleocin)

If patient develops diarrhea, the drug must be discontinued.

Warning!


metronidazole (Flagyl)

Place a do not drink alcohol warning sticker on this medication.

Adjunct in Treating Sepsis

• Sepsis is a life-threatening result of serious infections.

• Properties of drotrecogin alfa (Xigris)– Anticoagulant– Anti-inflammatory

• drotrecogin alfa (Xigris)

Adjunct in Treating Sepsis

Drug List

Discussion

Why is resistance developing to antibiotics? Is this a problem? What role can the pharmacy technician play in regards to this problem?

Health & Medicine

Chapter04 Antibiotics