Antibiotics Part 1 Flashcards
Sulfonamides include
Sulfamethoxazole-trimethoprim Others: Sulfamethoxazole Sulfisoxazole Sulfadiazine Sulfamethiozole
Mechanism of Action and Drug Effects: Sulfonamides
- Bacteriostatic (inhibits growth of bacteria)
- Inhibits folic acid synthesis (folic acid is required for proper synthesis of purines, a chemical component of nuclei can acids)
- Competitive inhibition (competes with PABA for bacterial enzyme tetrahydropteroic acid synthetase, which incorporates PABA into the folic acid molecule)
Indications for Sulfonamides
Broad spectrum: act against gram (+) and (-)
UTI’s
Respiratory Tract Infections
Pneumocystis Jerovecii (HIV associated pneumonia)
Skin and soft tissue infections
Infections due to Staph or MRSA
Contraindications to Sulfonamides
Allergy to sulfa
Cyclooxyrgenase-2 inhibitor (Celebrex)
Pregnant women at term and infants younger than 2 months
Sulfite so: preservatives in food, wine, injectable drugs.
Chemical components of folic acid
PABA
Adverse Effects of Sulfonamides
Allergic Reaction
Stevens Johnson Syndrome, Renal Damage from crystalluria, Kernicterus (bilirubin deposited in infants)
Delay cutaneous reactions, fever followed by rash
Photosensitive try reaction: skin reaction induced by exposure to sunlight, sunburn
Other: mucocutaneous, GI, hepatic, renal and hematologist complications
Immune mediated: involve production of reactive drug metabolites in the body
Interactions of Sulfonamides
Sulfonylureas, hypoglycemic effects in diabetes treatment
Phenytoin toxic effects
Warfarin anticoagulant effects hemorrhage
(Increased?) likelihood of cyclosporine-induced nephrotoxicity
(Decreased?)efficacy of oral contraceptives
Assessment of Sulfonamides
Drug allergies to sulfa type drugs or sulfites (oral sulfonylureas, thiazides diuretics)
Skin assessment during therapy d/t Stevens-Johnson syndrome
RBC count before therapy d/t possibility of drug related anemias
Renal function d/t potential for drug related crystalluria
Meds and med he for any manifestations of GSPD and slow acetylation.
Implementation of Sulfonamides
Avoid in pts w/ G6PD and slow acetylation
Fluids: 2000-3000 mL/24 hrs to prevent crytalluria
Take w/ food to minimize GI upset
Report: worsening abdominal cramps, stomach pain, diarrhea, blood in urine, severe or worsening rash, SOB, fever
Penicillins (PCNs) are divided into 4 subgroups
- Natural PCNs
- Aminopenicillins
- Penicillinase-resistant PCNs
- Extended spectrum PCNs
Natural PCNs include
Penicillin G and V
Aminopenicillins include
Amoxicillin
Ampicillin
Penicillinase-resistant PCNs include
Nafcillin
Dicloxacillin
Oxacillin
Cloacal lion
Extended spectrum PCNs include
Amoxicillin/clavulanic acid
Ampicillin/sulbactam
Ticarcillin/clavulanic acid
Piperacillin/tazobactam
Mechanism of Action and Drug Effects of PCNs
Bactericidal (kills a wide variety of gram (+) and some (-)
Inhibits cell wall synthesis -> formation of defective cells walls = cell death from lysis
Doesn’t affect human cells
Beta-Lactam Antibiotics have four major subclasses
- Penicillins
- Cephalosporins
- Carbapenems
- Monobactams
Beta-Lactam Antibiotics structure and MOA
Share a common structure and MOA
Inhibits synthesis of bacterial peptidoglycan cell wall.
Beta Lactamase inhibitors are added to
Penicillin AB. Makes drug more powerful against beta Lactamase bacterial strains. (Some bacterial strains produce enzyme: beta lactamase)
Beta Lactamase
Resists these antibiotics by breaking the chemical bond of C and N atoms in structure of beta-lactam ring loss of antibacterial efficacy.
Penicillins were first derived from a
mold (fungus) seen on bread or fruit
Penicillinases
Beta lactamase that inactivates penicillin molecules
Three beta lactamase inhibitors
Cleveland acid
Tazobatam
Sulbactam
Natural Penicillin
Only 2 in clinical use
Pen G: injectable or IV/IM use
Pen V: PO (tablet & liquid)
Penicillinase-resistant drugs
Stable against hydrolysis of staphylococcal Penicillinases
Aminopenicillins
has amino group attached
? activity against gram (-) bacteria compared with natural penicillins
Extended spectrum drugs
Wider spectra of activity compared to all other penicillins
Combos of Penicillin + Beta-lactamase inhibitors
ampi + sulbactam
amoxi + clavulanic acid
ticar + clavulanic acid
pipera + tazobactam
Indications for Penicillins
- to prevent and treat infections caused by gram (+) bacteria (strepto, entero, and staphylo -end coccus
- for prophylaxis (i.e amoxicillin)
- extended spectrum penicillins have gram + and - and anaerobic coverage: used in HAI (pneumonia, intraabdominal infections and sepsis)
Contraindications for Penicillins
drug allergy: very common, incidence (0.7% - 4%)
Adverse Effects of Penicillin
Related to drug allergies/Type 1 hypersensitivity reactions
mostly GI effects such as diarrhea, N/V, taste alterations, oral candidiasis