written Flashcards
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Adverse Effects of Penicillins:
1- Allergic Reactions: Urticaria, angioedema & Anaphylactic shock:
a- Avoid by: - Ask for previous history.
- Dermal sensitivity test.
b- Treatment of Anaphylactic shock: Adrenaline + Cortisol + Antihistaminic.
c- Never reuse penicillin again.
d- Cross allergy with Cephalosporins (10%).
2- Diarrhea due to superinfection, especially after oral Ampicillin:
a- Candida albicans — monilial thrush & diarrhea. Treat by Nystatin.
b- Antibiotic associated (Pseudomembranous) colitis. Caused by enterotoxins
produced by Staph. or Clostridium difficil. Treated by Oral Vancomyein or
Metronidazole.
3- CNS irritation (seizures) may occur with large doses in patients with renal failure or
intra-thecal injection of penicillin.
4-Ampicillin induces skin rash in 10% of patients & in ALL patients with infective
mononucleosis, leukemia & taking allopurinol.
5- Benzathine penicillin— Pain.-at site of injection.
6- Nafcillin case neutropenia
7- Oxacillin can cause hepatitis
APCD page 150
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Toxicity of Cephalosporins:
1- Allergy & partial Cross-allergy with penicillins (10%).
2- GIT upsets and Superinfections.
3- Irritant: - .M. — Painful, so add lidocaine.
- .V. - Thrombophlebitis.
4- Nephrotoxicity specially Cephaloridine
It is augmented by concurrent use of Frusemide and Gentamicin.
5- Ceftriaxone + Calcium — Insoluble salts in Bile — Biliary Sludge.
6- Cefamandole, Cefoxitin & Cefoperazone:
a- Hypoprothrombinemia (can be prevented by Vit K 10 mg twice weekly)
b- Disulfiram like action — Alcohol intolerance.
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vancomycin moa
Inhibits early steps of Cell wall synthesis — Peptidoglycan polymerization >Bactericidal.
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vancomycin uses
a- IV in MRSA & Enterococcal infections.
b- IV prophylactic before dental operations in patients with prosthetic valve or joint.
c- Orally in pseudomembranous colitis.
Monitoring of the plasma trough level may be necessary to confirm adequate
concentration
adverse effects of vancomycin
a- Ototoxic.
b- Nephrotoxic.
c- Rapid IV infusion — Histamine release —>Red man syndrome & Shock
the van is NOT RED
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Mechanism of Action of aminoglycosides
They bind to 30 S ribosomal subunit leading to inhibition of
bacterial protien synthesis
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uses of aminoglycosides
A) Systemic use: gentamicin, amikacin, tobramycin, and netilmicin
1. Used in serious gram-negative infections (Klebsiella, Proteus,
Pseudomonas, Enterobacter & Serratia), and Staphylococcal & Enterococcal
infections.
2. When Pseudomonal infections it may be necessary to add a beta lactam with
antipseudomonal action such as piperacillin/tazobactam [Tazocin]
3. Bacterial endocarditis. Add Benzyl penicillin.
B) Topical uses:
1. Topical neomycin or gentamicin (Cream, ointment or Solution) in burns, wounds &
skin lesions.
2. Oral neomycin for gut de-contamination: It is not absorbed but acts locally in the
GIT
C) used in TB streptomycin
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Toxicity of Aminoglycosides:
ototoxicity
nephrotoxicity
Teratogenic
neuromuscular blockade
allergic manifestation
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Anti-Bacterial Activity of Tetracyclines:
Concentrated in bacteria by specific transport proteins unique to bacterial cytoplasmic membrane. Attach to 30 8 ribosomal subunits leading to inhibition of
protein synthesis.
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antibaxterial activity of marcolides
- They bind irreversibly to 50 S ribosomal subunits leading
to inhibition of Translocation leading to decreased Protein synthesis. - Bacteriostatic and cidal
- Selectivity: Humans have different ribosomal subunits
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theerpeutic uses of marcolides
- Drug of CHOICE in Bordetella pertussis.
- Drug of CHOICE in corynebactrial infections e.g. Diphtheria.
- Drug of CHOICE in Atypical Pneumonia caused by Mycoplasma &
Legionella. - Drug of CHOICE in Chlamydial infection: Respiratory, Genital & ocular.
Specially in Neonates & Pregnancy. - Sexually transmitted diseases (STD): Gonorrhea, Syphilis & Chlamidia.
- Penicillin substitute in Staph., Strept.& Pneumococcal in patients allergic to
penicillin. - In rheumatic patients taking penicillin as prophylaxis priorto dental
procedures to avoid bacterial endocarditis.
Topically in Acne vulgaris.
BAPA SCCR
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Adverse Effects of Macrolides:
- Most common is Epigastric pain. Erythromycin > Others.
- Cholestatic jaundice.
- Large doses of erythromycin — Reversible Ototoxicity.
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Anti-Bacterial Activity of Fluoroquinolones
They enter the bacteria by passive diffusion through the porins —_inhibit Bacterial Topoisomerase Il (DNA gyrase) & Topoisomerase IV enzymes — Inhibition of DNA gyrase prevents the relaxation of supercoiled DNA required for normal transcription and replication. Inhibition of topoisomerase IV interferes with separation of replicated chromosomal DNA into daughter cells during cell division — decrease DNA Replication > BACTERICIDAL.
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Therapeutic uses of fluorquinolones
Infections of the urogenital & GIT tract caused by gram negative organisms.
Respiratory, skin & soft tissue infection.
Gonorrhea
Resistant T.B
Typical & atypical pneumonia
Tract infection and tb and typtical and atypical pneumonia
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adverse effects of fluorquinolones
GIT upsets: (most common).
. Allergy: skin rash
Photosensitivity, use sun-screens & sun-blocks.
. CNS: Headache, dizziness & confusion, insomnia.
Seizures specially if used with NSAID — Avoid in Epileptics.
Chondrolytic— Reversible arthropathy — Avoid in pregnancy, lactation and in
children up to age of 18 years.
Rupture of tendons (Achilles tendon) specially in elderly taking glucocorticoids.
Nephrotoxic & Crystaluria.
The 3 generation may cause prolongation of Q-T intervalGIT upsets: (most common).
. Allergy: skin rash
Photosensitivity, use sun-screens & sun-blocks.
. CNS: Headache, dizziness & confusion, insomnia.
Seizures specially if used with NSAID — Avoid in Epileptics.
Chondrolytic— Reversible arthropathy — Avoid in pregnancy, lactation and in
children up to age of 18 years.
Rupture of tendons (Achilles tendon) specially in elderly taking glucocorticoids.
Nephrotoxic & Crystaluria.
The 3 generation may cause prolongation of Q-T interval
