Antibiotics Flashcards
What are the 3 General Mechanisms of Bacterial Destruction?
Cell Wall Disruption
Enzymatic Inhibition
Protein Synthesis Disruption
Name the general Beta Lactam Antibiotics (PCCM) and the mechanism of action
Penicillin Cephalosporin Carbapenems Monobactams MOA: Bactericidal effects by interfering with ability to form the cell wall; cell swell and burst
What is Beta Lactamase and name the three Beta Lactamase Inhibitors (-bactam +CA)
Beta Lactamase is produced by bacteria to inactivate antibiotics
Sulbactam
Clavulanate (Clavonic Acid)
Tazobactam
What is penicillinase and name the 4 Penicillinase Resistant Penicillins (think oxa +Naf)
Some bacteria produce penicillinase that destroys beta lactam ring - making penicillin ineffective Dicloxacillin Cloxacillin Oxacillin Naficillin
Do not mix penicillin with ____ in same IV solution
b/c it inactivates _____.
Aminoglycosides for both answers (usually added to regime to increase killing of pseuonomas)
What are the penicillin A/E
GI: N/V & Diarrhea & Abd Cramp
Glossitis -inflammed tongue, Somatitis - swelling/sores in mouth, Furry Tongue
Hypersensitivity Rxn: Rash
Pruritus (itching)
Fever
Anaphylaxis (5-10% of ppl- within 2-30min ):
Laryngeal Edema
Bronchoconstriction
Hypotension
Pain/Itching @ injection site
Name the three alternatives to use and the two not to use if penicillin anaphylactic reaction is intact?
Which one can be used if there is simply a mild allergy to PCN?
Use: Vancomycin, Clindamycin, Macrolides
Avoid: Cephalosporin or Carbapenems (cephalosporin can be used as alternative if mild allergy to PCN)
What is the name of the broad spectrum Penicillin that can cross BBB?
Ampicillin
Amoxicillin is the only other broad spectrum in class - both inactivated by beta lactamase
What are the beverages to avoid when taking penicillin - can decrease effectiveness
Caffine-containing beverages
Fruit Juices
Tomato Juice
(and citrus fruits)
How many generations of cephalosporins are there?
5 (all cephalosporins commonly start with cef or cep)
1st and 2nd generation cephalosporin commonly used against ______ and limited against ____.
Used: Gram Positive
Limited: Gram Negative
Name the two common 1st Generation Cephalosporin Drugs (think ceph)
Cephalexin & Cephazolin
Name the two common 2nd Generation Cephalosporin Drugs (think cef)
Cefoxitin
Cefuroxime
Name the two common third generation cephalosporin drugs (think ceft)
Ceftazidime
Ceftriaxone
Which generation is the only cephalosporin approved to treat MRSA - Name the drug
5th Generation (Ceftaroline)
Which generation of cephalosporin is used against gram negative microbes?
Third Generation
Ceftazidime is active against pseudomonas. What drug class is often given to enhance it’s killing effects?
Aminoglycosides
Which generation of cephalosporin is most effective against meningitis?
Third Generation
Which two cephalosporin generations are possibly responsible for C.Diff spread?
Third and Fourth
What are the cephalosporin A/E
(Common to penecillin)
Diarrhea, Abd cramps, Rash, pruritis, redness, edema
What happens when cephalosporin interacts with antacid, iron, probenecid, or oral contraceptives?
Antacids & Iron - Dec. effectiveness of drug
Probenecid - Dec. renal excretion
Oral Cont. - Enhances OCP metabolism; inc. risk of pregnancy
When given ceftriaxone and calcium together, what happens? (in neonates)
Necessary precautions to take?
Form fatal precipitates (solids that fall out into sol’n) in lungs and kidney
Dont give through same line OR differeent lines unles 48 hours in between them - In all other patients, may be given sequentially through same line (must flush between solutions)
What is the cephalosporin drug that can not be given with calcium?
Ceftriaxone
Which antimicrobial drug class has the broadest action of all antibiotics up to date?
Carbapenems
What are the drugs in carbapenem class?(give suffix)
-penem
Carbapenems must be infused for how long?
over 60 minutes
All carbapenems interacts with ____ to reduce blood levels of that drug. (what is drug used for)
What is the effect?
Valproate - used to control seizures
May cause seizures (also lowers seizure threshold)
What are the carbapenems A/E?
Similiar to penicillin
- mild diarrhea, abd cramps, rash, pruritis, redness, edema
Imipenem is rapidly inactivated by _______ (enzyme in kidney)
Which drug is combined to inhibit that enzyme?
Dipeptidase; 70% of imipenem is excreted unchanged in urine - 1/2 life of about 1 hour because of this enzyme
Cilastatin inc. half life and tissue penetration
Only monobactam drug in class?
Azactam
All A/E and MOA in these classes of antibiotics are very similar, almost identical - Name them
Penicillin
Carbapenems
Cephalosporins
Monobactam
What is the name of aminoglycosides? (suffix)
What is their MOA?
Concentration or time dependent?
-mycin
rapid bactericidal action through disruption of protein synthesis (30S Ribosome) - Concentration dependent
Aminoglycosides are used to treat aerobic or anaerobic bacteria / gram negative or gram positive? bacteria?
Aerobic gram negative bacteria
(“glycosides” require O2 for transport across bacteria cell membrane- anaerobic environment doesn’t allow transport)
Inactive against most gram positive bacteria
Which aminoglycoside is least susceptible to inactivation by bacterial enzymes?
Amikacin
Two major adverse effects of aminoglycosides (NO!)
Ototoxicity - impairment of hearing and balance; can be irreversible; R/T excessive trough levels (NOT Peak)
Nephrotoxicity - generally reversible; binds tightly to renal tissue achieving 50x dose of that in serum levels -> Acute Tubular Necrosis
Other A/E of aminglycosides?
Hypersensitivity rxn: rash, pruritis (itching), urticaria (hives)
Blood Dyscrasias
Neuromuscular blockade –> causes paralysis of affected skeletal muscle
What is the name of macrolides? (suffix)
What is their MOA?
-thromycin
inhibition of protein synthesis (50s ribosome)
Do not administer metal ions 2 hours before or after taking this drug in macrolide class?
Azithromycin (Some antacids contain metal ions)
What is function of cytochrome p450? Which drug in macrolide class is the only one that does not affect this enzyme? All others do what to it?
Metabolize toxic compounds (drugs)
Azithromycin
All others inhibit p450 - inc. toxicity of drug in body
Macrolides A/E (specifically erythromycin)?
GI: Hepatotoxic, Heartburn, Flatulence, N/V & Diarrhea
CV: Prolonged QT interval
Thrombophlebitis, hearing loss, and (pyloric stenosis in infants)
Can macrolides (specifically erythromycin) cross placenta and CSF?
Placenta - yes
CSF - no
Azithromycin A/E?
Sun sensitivity and diarrhea
Which two macrolides have similar A/E?
Erythromycin & Clarithromycin
Tetracylines has ability to bind with metallic ions and form insoluble compounds. Therefore avoid taking ____ when on this medication
Antacids
What is name of tetracyclines? (suffix)
What is MOA?
-cyclines
Inhibit bacterial protein synthesis (30s ribosome)
3 antibiotic classes contraindicated in pregnancy?
Tetracycline Sulfonamides Quinolones Flagyl Chloramphenicol
Which drug in tetracycline class to give in pt with SIADH (syndrome of inappropriate anti-diuretic hormone)?
Demeclocycline - inhibits ADH
Can tetracyclines penetrate BBB & CSF?
Yes - specifically minocycline and doxycycline
All other tetracyclines have reduced absorption when taken with food except?
Minocycline
Avoid these items when on tetracyclines
Iron, calcium products, Magnesium & aluminum (laxatives/Antacids), Zinc
Can decrease efffectiveness of OCP
Unique A/E of tetracyclines?
Teeth discoloration Photosensitivity Rxn Yeast Infection Exacerbation of Lupus Buldging Fontanelles Thrombocytopenia/anemia
What are names of the quinolones? (suffix)
MOA?
-floxacin
destroy bacteria by altering bacteria DNA
Unique A/E of quinolones?
Black Box Warning: ruptured tendons & tendonitis
CNS: Altered mental status, convulsions, depression, dizziness
GI: N/V Flautulence, Heartburn, Diarrhea, oral candidiasis
CV: prolonged QT interval
Skin: Rash, Pruritis, Flushing, Urticaria - Photosensitive
Quinolone interaction with dairy products, antacids and other metallic ions, and probenecid?
Dairy, Antacids, and metallic ions - Reduce asorption
Probenecid - Reduce excretion
What is probenecid?
Renal Tubular Transport Blocking Agent
Name of sulfonamides? (pre-fix)
MOA?
Sulfa
Prevents bacteria synthesis of folic acid –inhibiting growth (bacteriostatic)
If patient has known sulfa allergy, do not give drugs of this class
COX 2 Inhibitors
Sulfa drug-drug interactions with warfarin and phenytoin
Warfarin - inc. risk of bleeding
Phenytoin - Inc. toxicity
Unique Sulfa A/E
Steven Johnson Syndrome Kernicterus (Neurotoxic) - bilirubin deposition in brain of newborns Convulsion Anemia/Thrombocytopenia Photosensitivity Rxn Delayed skin Rash & pancreatitis
Which class of antibiotics to avoid if pt has G6PD deficiency?
Sulfonamides
Oral anticoagulants (warfarin) taken with ______ can prolong INR leading to bleeding
Quinolone
DOC for MRSA and severe C.Diff?
Vancomycin
A/E of Vancomycin?
Red Man Syndrome - flushing/itching of head and neck, hypotension; all from rapid IV infusion
Ototoxicity (may be permanent or reversible)
Nephrotoxicity
MOA of Vancomycin
Destroys bacterial cell wall
How long should vancomycin be infused if given IV?
over 60 minutes
Clindamycin MOA?
inhibits protein synthesis - normally bacteriostatic but @ high doses it is bactericidal
Unique A/E of clindamycin?
Steven Johnson - first appears as flu like symptomes then develops into painful rashes, blisters, and eye redness
EKG Changes - caused by rapid IV infusion
C.Diff!!
What is C.Diff?
Which antibiotic can cause C.Diff?
normally harmless microflora in GI; external stimulus upsets gut causing abnormal overgrowth and release of toxins attacking the lining of intestines (Pseudomembranous colitis)
Clindamycin
Which drug is used against multi-drug resistant gram positive pathogens? (eg Vancomycin resistent enterococci and Methicillin resistant staphylococcus aureus)
Linezolid
Which drug is used as prophylaxis in abdominal surgery, vaginal surgery, and colorectal surgery?
Metronidiazole (Flagyl) - also used in protozoal infections and for C diff
Which drug can cause fatal aplastic anemia and grey baby syndrome(vomiting, abd distension, cyanosis, grey skin discoloration)?
Why use this drug?
Chloramphenicol
Used only for life-threatening infections for which safer meds are ineffective
Name three antibiotic classes that have adverse photosensitivity effect
Sulfonamides, tetracyclines, quinolones
Which antibiotic class should be taken with food and can cause antabuse-like rxn when taken with alcohol?
Cephalosporins
This antibiotic may produce red/brown urine
Flagyl
