Antibiotics Flashcards
Sulfonamides (Septra)
- Mechanism of action: do not destroy bacteria but inhibit the growth of susceptible bacteria by preventing bacterial synthesis of folic acid (folic acid is needed for synthesis of DNA)
- Indication: Sulfonamides have a broad spectrum of antibacterial activity, including activity against both gram-positive and gram-negative organisms.
Commonly used for UTIs, MRSA skin infections - Contraindications: known allergy to sulfonamides, sulfa allergy, pregnant women (cause it decreases folic acid absorption), infants younger than 2 months of age
- Adverse effects: Photosensitivity, allergies, steven johnson syndrome, rash, GI, liver, renal complications
- Interactions: ACE inhibitors, some diabetes medications, dilantin, warfarin
Penicillin
Type of beta-lactam antibiotic
Example: Penicillin V
- Mechanism of action: inhibit the synthesis of the bacterial peptidoglycan cell wall.
- Indication: kill a wide variety of gram-positive bacterial infections, Strep, staph
- Contraindications: hypersensitivity to penicillin or component of medication. Possible cross sensitivity can occur with other beta-lactams
- Adverse effects: superinfections (yeast), rashes, urticaria, angioedema, idiosyncratic reactions, and GI upset
Cephalosporins (cephalexin, keflex)
Related to penicillins
- Mechanism of action: are bactericidal and act by interfering with bacterial cell wall synthesis
Dosed 4x day, which is challenging for some - Indication: broad spectrum – can be used for gram +, gram – and anaerobics
1st generation most gram +
Later generations are more gram - - Contraindications: Hypersensitivity to cephalosporins, or any component of the formulation
- Adverse effects: Similar to penicillins → superinfections, rashes, urticaria, angioedema, idiosyncratic reactions, and GI upset
Macrolides
- Mechanism of action: bacteriostatic drugs that inhibit protein synthesis by binding reversibly to the 50S ribosomal subunits of susceptible microorganisms
- Indication: variety of infections – group A strep, respiratory infections, H. influenzae, chlamydia & syphilis
- Contraindications: known drug allergy
- Adverse effects: QT prolongation, chest pain, headache, GI upset, rash, urticaria/allergic rxn, hearing loss/tinnitus
- Other common macrolides: azithromycin, clarithromycin, erythromycin
Tetracycline
- Mechanism of action: bacteriostatic, inhibit bacterial protein synthesis by binding to the 30S bacterial ribosome
- Indication: variety of infections – both gram +/gram -. Useful for acne, Lyme disease, syphilis, chlamydia, pelvic inflammatory disease, respiratory infections, skin infections, and many others
- Contraindications: known drug allergy. However, tetracyclines must be avoided by pregnant and nursing women and should not be given to children under the age of 8 years.
- Adverse effects: discolouration of teeth (especially children), photosensitivity, superinfections, GI upset, rash, and allergic reaction
- Can interact with various medications such as: calcium, iron, dairy, anti-acids, affecting absorption. It can also affect oral anticoagulants
Aminoglycosides
- Potent antibiotics → good for virulent infections
- Serum levels of these drugs are monitored to ensure toxicity does not occur
- Mechanism of action: inhibit protein synthesis in bacteria by binding irreversibly to the 30S ribosomal subunit (similar to tetracyclines)
- Indication: serious gram - infections and specific gram + infections (cocci); however, topical neomycin for mild skin infections
- Adverse effects: ototoxicity, nephrotoxicity, GI upset
- Examples: gentamicin, neomycin, streptomycin, tobramycin
- Contraindications: known drug allergy, pregnant women, children, breastfeeding
Quinolones
- Bactericidal, broad spectrum antibiotics
- Mechanism of action: destroy bacteria by altering their DNA
Mostly gram - some gram + - Indication: Potent broad spectrum antibiotic; UTIs and infections of the dermatological, respiratory, MSK and GI systems.
- Examples: ciprofloxacin, levofloxacin, moxifloxacin, norfloxacin
- Contraindications: known drug allergy
- Adverse effects: Rare risk of tendinitis and tendon rupture; QT prolongation ***; renal dysfunction; GI upset; rash, allergic reaction, superinfections, headache and dizziness
- Interactions? vitamins, anti-acids, dairy, nitrofurantoin, and warfarin
Clindamycin
inhibits proteins synthesis in bacteria
Good for acne, staph, strep, MRSA, pneumonia
Adverse effects: GI upset
Linezolid
is the first antibacterial drug in a new class of antibiotics known as oxazolidinones
Acts by inhibiting bacterial protein synthesis
Good for VRE, MRSA
Metronidazole
is an antimicrobial drug of the class nitroimidazole
It has good activity against anaerobic organisms
Good for intra abdominal, gynecological infections, C Diff, rosacea, diabetic foot ulcers
*** can interact with alcohol
Nitrofurantoin
is in the class nitrofuran
works by interfering with the activity of enzymes that regulate bacterial carbohydrate metabolism and by disrupting bacterial cell wall formation
Good for complicated UTIs
Okay for early pregnancy
Vancomycin
is a natural bactericidal antibiotic that is structurally unrelated to any other commercially available antibiotics
destroys bacteria by binding to the bacterial cell wall, producing immediate inhibition of cell wall synthesis and death
Good for bone and joint infections, C Diff, bacterial bloodstream infections, MRSA and gram +
Adverse effects: nephrotoxicity, ototoxicity, red man syndrome, GI upset, superinfections
