Pharmacology: Antibiotics/virals for LRTI Flashcards
Amoxicillin & Cefotaxime MOA?
Inhibits cell wall synthesis by preferentially binding to specific penicillin-binding-proteins (PBPs) located inside the bacterial cell wall (transpeptidases) → Inhibits peptidoglycan cross-linking in bacterial cell wall → Cell lysis (Bactericidal)
Adverse effects of Amoxicillin & Cefotaxime?
- Nausea/vomiting, diarrhea
- Mainly hypersensitivity reaction
- Exhibit cross-sensitivity or cross-allergenicity
Resistance to Amoxicillin & Cefotaxime?
Resistance:
- Inactivation of the drug by β-lactamases
- structural differences in PBPs
- presence of permeability barrier (mainly gram -)
How can we avoid inactivation of Amoxicillin by β-lactamase?
We give it alongside clavulinic acid (a β-lactamase inhibitor)
What is Clavulinic acid?
A β-lactamase inhibitor
Which class of drug does erythromycin belong to?
Macrolides
Erythromycin MOA?
Inhibits protein synthesis by binding to the 50s subunit of bacterial ribosomes
Which enzyme does erythromycin inhibit? The consequences of that?
Cytochrome-P450 (this affects the metabolism of other drugs and destroys gut flora)
Adverse effects of Erythromycin?
Adverse effects:
- Hypersensitivity reactions
- GI disturbances, cholestatic jaundice,
- Reversible ototoxicity
Which class of drug is Ciprofloxacin?
Fluoroquinolone
MOA of Ciprofloxacin?
Inhibits DNA gyrase (topoisomerase II) topoisomerase IV → Inhibits replication of DNA → Cell death (Bactericidal)
Which class of drug is Co-trimoxazole (Sulfamethoxazole & Trimethoprim)?
Sulfanomides
MOA of Co-trimoxazole (Sulfamethoxazole & Trimethoprim)?
inhibit folate synthesis
Which antibiotic is used to treat Pneumocystis corinii infection in patients with AIDS ?
Sulfanomides:
Co-trimoxazole (Sulfamethoxazole & Trimethoprim)
Adverse effects of Co-trimoxazole (Sulfamethoxazole & Trimethoprim)?
Adverse effects:
- Nausea/vomiting, headache, mental depression
- Serious effects of sulfonamides are hepatitis, hypersensitivity reactions, bone marrow depression & crystalurea
MOA of Tetracycline?
Binds to 30S ribosomal subunit inhibiting protein synthesis
Is Tetracycline bacteriostatic or bactericidal?
Bacteriostatic but bactericidal at high concentrations
Tetracycline adverse effects?
Adverse effects:
- Diarrhea, vomiting, abdominal pain, anorexia, hepatotoxicity
- Serious effect on developing teeth (permanent yellow/brown)
Which class of drugs does Linezolid belong to?
Oxazolidinones
Linezolid MOA?
Inhibits protein synthesis
Linezolid is used to treat ______? And is quite effective in which infections?
used to treat MRSA, and quite effective in vancomycin-resistant gram (+) infections
Adverse effect of Linezolid? (1)
Bone marrow toxicity
What type of drug is Vancomycin?
Glycopeptide
MOA of Vancomycin?
Acts on cell wall synthesis
- binds to precursors of cell wall synthesis and inhibits peptidoglycan elongation
- binding occurs at (D-Ala-D-Ala residue)
MOA of Vancomycin?
Acts on cell wall synthesis
- binds to precursors of cell wall synthesis and inhibits peptidoglycan elongation
- binding occurs at (D-Ala-D-Ala residue)
Vancomycin is active against? (3)
- MRSA
- S.epidermidis
- G+ bacteria in p/x allergic to penicillin
Adverse effects of Vancomycin? (2)
- Ototoxicity
- Nephrotoxicity
What type of drug is Chloramphenicol?
Amphenicol
Chloramphenicol MOA?
M.O.A: Binds to 50S & inhibits mitochondrial protein synthesis
Chloramphenicol adverse effects?
Hematological effects & Gray baby syndrome
What is Ganciclovir?
An analogue of Acyclovir
What is Ganciclovir?
An analogue of Acyclovir
Ganciclovir MOA?
M.O.A: Phosphorylated by CMV kinases → forms triphosphate → inhibits CMV DNA polymerase → which Inhibits viral nucleic acid synthesis
Ganciclovir is active against which viruses?
Active against Herpes virus – H. Simplex, H. Zoster, EBV and CMV
How is Ganciclovir usually given? And how is it excreted
IV and is excreted in urine
Ganciclovir’s active metabolite attains a higher concentration of where?
Its active metabolite attains higher concentration inside CMV cells
Ganciclovir adverse effects?
Adverse Effects:
o Systemic toxicity is high, bone marrow toxicity (anemia, leukopenia)
o rashes, fever, vomiting, neuropsychiatric disturbances
Ganciclovir adverse effects?
Adverse Effects:
o Systemic toxicity is high, bone marrow toxicity (anemia, leukopenia)
o rashes, fever, vomiting, neuropsychiatric disturbances
Which antiviral medication is used only for prophylaxis and treatment of severe CMV infections in immunocompromised patient ?
Ganciclovir
Uses of Amantadine?
- Influenza-A (seasonal flu) for reducing fever, congestion, cough for fast recovery
- In Parkinson’s disease (for anticholinergic effects)
Adverse effects and contraindications of Amantadine?
Adverse effects:
o Nausea, anorexia, insomnia, dizziness, nightmares
o Mental confusion, & ankle edema
• Contradicted in CNS disease, GI ulcer, & pregnancy
Compare Rimantadine with Amantidine
Its methyl derivative that’s more potent, longer acting, better tolerated, and lower side effects than Amantadine
What type of drug is Oseltamivir?
Protease and Release Phase Inhibitors (Neuraminidase inhibitors)
Oseltamivir is active against which viruses?
Active against 🐦
- influenza virus (Amantadine sensitive/resistant)
- H5N1 (Bird flu)
- H1N1 (Swine flu) strain
What kind of drug is Palivizumab?
Immunomodulator
What can palivizumab prevent?
can prevent RSV infections, from high risk of serious respiratory complication in babies
