Antibiotics: Part 2 Flashcards
Persisting suppression of bacterial growth after only a limited exposure to the drug.
Post-antibiotic Effect
What are the most common Tetracyclines?
Tetracycline
Doxycycline
Minocycline
Are Tetracyclines bactericidal or bacteriostatic
Bacteriostatic
What is the mechanism of action of Tetracyclines?
Protein Synthesis Inhibition
(30s subunit)
What are some adverse drug reactions of Tetracyclines?
Photosensitivity
GI Intolerance
Stain Developing Teeth (less than 8 years old)
What will decrease the absorption of Tetracyclines?
Polyvalent Cations
- Ca²⁺
- Ma²⁺
(wait two hours before or after)
What type of patients can you NEVER give Tetracyclines to?
Pregnant
Tetracyclines are the drug of choice for which infections?
Tick-borne diseases (Rocky Mountain Spotted Fever)
Chlamydia
What are some common examples of Macrolides?
Erythromycin
Clarithromycin
Azithromycin
Are Macrolides bacteriostatic or bactericidal?
Bacteriostatic
What is the mechanism of action for Macrolides?
Protein Synthesis Inhibition
(50s subunit)
Clarithromycin and Erythromycin cause major drug interactions by doing what?
Inhibiting CYP450
What is an adverse drug reaction of Macrolides?
QT segment prolongation
Macrolides are the drug of choice for which infections?
Chlamydia (Azithromycin)
H. pylori (Clarithromycin)
What are some examples of Oxazolidinones?
Linezolid
Tedizolid
Are Oxazolidinones bacteriostatic or bactericidal?
Bacteriostatic
What is the mechanism of action of Oxazolidinones?
Protein Synthesis Inhibition
(50s subunit)
Oxazolidinones should be used with caution when a patient is taking an Sympathomimetics and SSRI because?
Weak Monoamine Oxidase (MAO) Inhibitor
What is an adverse drug reaction of Oxazoldinones?
Thrombocytopenia
Oxazolidinones are good for treating what types of infections?
Gram Positive Cocci
- MRSA
- VRE
SSTIs & Hospital Associated Pneumonia
What is an example of a common Lincosamide?
Clindamycin
Is Clindamycin bacteriostatic or bactericidal?
Bacteriostatic
What is the mechanism of action of Clindamycin?
Protein Synthesis Inhibition
(50s subunit)
Clindamycin can cause bacteria exposed to concentrations of antibiotic higher than an optimal bactericidal concentration to have paradoxically improved levels of survival. What is this known as?
Eagle Effect
What is adverse drug reaction caused by Clindamycin?
Gastrointestinal Intolerance
(including C. difficile)
What type of infections are Clindamycin used to treat?
SSTIs
Oral infections
Anaerobic Intra-abdominal Infections
Acne (topically)
What is an example of a folate antagonist?
Sulfamethoxazole and Trimethoprim
(Bactrim)
Is Bactrim bactericidal or bacteriostatic?
Bactericidal (combination)
What is the ratio of Trimethoprim to Sulfmethoxazole in Bactrim?
1 part Trimethoprim
5 parts Sulfamethoxazole
(1:5 ratio)
Bactrim has a drug to drug interaction with what other medication?
Warfarin
(displaces warfarin from Albumin)
Bactrim is good for treating what type of infections?
UTIs
SSTIs
GI infections
Bactrim is the drug of choice for what?
Pneumocystis jiroveci (pneumonia)
What are some examples of common Fluoroquinalones?
Ciprofloxacin
Levofloxacin
Moxifloxacin
Are Fluoroquinolones bactericidal or bacteriostatic?
Bactericidal
What is the mechanism of action of Fluoroquinalones?
DNA Gyrase Inhibition
Rare side effects caused by Fluoroquinalones?
QT prolongation
Achilles Tendon Rupture
What patient population contraindicates the administration of Fluoroquinalones?
Pregnant Women (Absolute)
Children (Relative)
What drug do Fluoroquinalones interact with due to polyvalent cation binding?
Warfarin
(inhibits metabolism)
What should Ciprofloxacin never be used to treat?
Respiratory Infections
Fluoroquinalones are the drug of choice for what type of infections?
Complicated UTIs
Severe Community Acquired Pneumonia (not Cipro)
Is Metronidazole (Flagyl) bactericidal or bacteriostatic?
Bactericidal
What is the mechanism of action of Metronidazole?
DNA Helical Structure disruption
What are some common side effects of Metronidazole?
Metallic Taste
Dark Urine
What drugs have an interaction with Metronidazole?
Disulfiram-like reaction with Alcohol (EtOH)
Warfarin (↑ INR)
What organisms are Metronidazole reliable against?
Gram (+) and (-) Anaerobes
Metronidazole is the drug of choice for what two pathologies?
Vaginal Trichomoniasis
C. difficile (Mild to Moderate)
Is Nitrofurantoin bactericidal or bacteriostatic?
Both (depends on concentration)
What is the mechanism of action for Nitrofurantoin?
Damages DNA and RNA
What type of patients cannot use Nitrofurantoin?
Poor Renal Function (CrCl < 50mL/min)
What are two rare adverse drug reactions caused by Nitrofurantoin?
Peripheral Neuropathy
Pulmonary Fibrosis
Nitrofurantoin is the drug of choice for what pathology?
Uncomplicated UTIs (Pregnant)
Gram-negative diplococcus sexually transmitted infection?
Neisseria gonorrhea
What is the treatment for gonorrhea?
Ceftriaxone
500mg (< 150kg)
1g (>150kg)
What is the treatment for Chlamydia trachomatis?
Doxycycline
(100mg BID x7 days)
Azithromycin
(1g)
Facultative anaerobic protozoan trophozoite that causes a malodorous, yellow-green discharge, dyspareunia, and strawberry cervix.
Trichomonas Vaginalis
What is the treatment for Trichomonas Vaginalis?
Metronidazole (Flagyl)
Gram (-) spirochete bacteria (Treponema pallidum) that causes painless chancres and is highly communicable. Occurs in multiple stages.
Syphilis
What is the treatment for Syphilis that has been ongoing for less than a year?
Benzathine Penicillin G
Strep throat is commonly caused by what bacteria?
Group A beta-hemolytic streptococcus
(GABHS)
How do you treat Strep Throat?
Penicillin VK preferred (but is not palatable to kids)
Amoxicillin is typically used
How do you treat Strep Throat in patients who have a penicillin allergy?
Keflex (Cefalexin) - if no history of anaphylaxis
Macrolide or Clindamycin - if history of anaphylaxis
Examples of consolidated pneumonias?
Strep. pneumo
Staph. aureus
H. flu
Legionellosis
Examples of atypical pneumonias?
Walking Pneumonia (mycoplasma pneumoniae)
Psittacosis (chlamydia psittaci)
Legionellosis
Q fever (coxiella burnetti)
Pneumocystis jiroveci pneumonia (PCP)
Cryptococcosis (cryptococcus neoformans)
What is the treatment of choice for community acquired pneumonia in a healthy person?
Doxycycline
(100mg x2 a day)
What is the treatment of choice for community acquired pneumonia in a person with comorbidities?
Macrolide or Doxycycline + B-lactam
What organisms can cause Toxic Shock Syndrome?
Staph. aureus
Coagulase-negative staphylococci
Streptococci
Mycoplasma arthritidis
How do you treat Toxic Shock Syndrome that is caused by MSSA?
Nafcillin or Oxacillin + Clindamycin
How do you treat Toxic Shock Syndrome that is caused by MRSA?
Vancomycin + Clindamycin
How do you treat Toxic Shock Syndrome that is caused by streptococci?
Penicillin G + Clindamycin
Vancomycin + Clindamycin (PCN Allergy)
Inflammation of the apocrine sweat glands. Commonly seen in the axilla, inguinal, and inframammary folds.
Hidradenitis Suppurativa
What is the treatment for Hidradenitis Suppurativa?
Topical Benzoyl Peroxide or Clindamycin 1% + Doxycycline (100mg x2 daily for 12 weeks)
- May need derm referral and biologics (Humira)
Red with well demarcated borders and very painful. Typically occurs on the face. Appears red, warm, and swollen with high fevers. Looks similar to cellulitis but will progress to sepsis if left untreated.
Erysipelas
What organism causes Erysipelas?
Group A Strep. (GAS)
What is the treatment of choice for Erysipelas?
Dicloxacillin (IV)
First Gen. Cephalosporins
Antibiotics that cover Anaerobes
(CAMP MUC)
Clindamycin
Augmentin
Metronidazole
Piperacillin/Tazobactam
Moxifloxacin
Unasyn
Carbapenems