Antimicrobials: Part 6: Adverse effects of drugs that work within the cell wall + membrane

Question 1

What are the adverse effects of penicillin G, V?

Answer 1

All penicillins have the same common thread adverse effect: hypersensitivity! See pic below. Every type of hypersensitivity reaction is associated with penicillin.

• Note: the anemia pertaining to type II hypersensitivity reaction is direct Coomb’s +
• Note: the nephritis on type IV is technically “drug-induced interstitial nephritis”
• Also, C. diff is possible (lower on the list, but yeah)

Question 2

What are the adverse effects of amoxicillin and aminopenicillins?

Answer 2

• Both aminopenicillins have hypersensitivity reactions (immediate, the same ones as natural penicillins) AND a rash (non-immediate) that occurs days to weeks after starting (type IV rxn). This type of rash is more common in aminopenicillins than the natural ones. These rashes that develop are more common in patients with viral infections.
• Patients with EBV virus that receive amoxicillin under the impression it is just strep throat can develop a rash
• Tips off that it is EBV!
• SJS can occur/toxic epidermal necrolysis

Question 3

What are the adverse effects of penicillinase-resistant penicillins?

Answer 3

Same hypersensitivity side effects as natural penicillins

Question 4

What are the adverse effects of antipseudomonals?

Answer 4

Same hypersensitivity side effects as natural penicillins

Question 5

What are the adverse effects of cephalosporins, generations I-V?

Answer 5

• Hypersensitivity side effects seen with other penicillins
• Bleeding, because…
• Vitamin K deficiency because this antibiotic can reeeally kills the bacteria that produces it
• Hypoprothrombinemia: some side chains on the antibiotics inhibit epoxide reductase → decrease in clotting factor synthesis
• Increase the nephrotoxicity of aminoglycosides
• Can have cross-reaction in patients with a penicillin allergy
• Disulfiram reaction

Question 6

What are the adverse effects of carbapenems?

What is special about imipenem?

Answer 6

• Mainly nausea, vomiting, diarrhea, and skin rash
• Seizures can occur due to inhibition of GABA especially at high doses and with renal failure
• Lower risk of seizures with meropenem

+

-Imipenem is metabolised in kidney by dihydropeptidase I

-Always given with cilastatin as to inhibit the enzyme → leads to improved effects and decreased nephrotoxicity

Question 7

What are the adverse effects of monobactams?

Answer 7

-Synergistic with aminoglycosides -No cross reactivity with penicillin allergic patients -Otherwise usually non-toxic

Question 8

What are the adverse effects of vancomycin?

Answer 8

• Nephrotoxicity
• Ototoxicity
• Thrombophlebitis
• Diffuse flushing → red man syndrome → due to direct activation of mast cells which lead to histamine release → NOT A HYPERSENSITIVITY REACTION

Question 9

What are the adverse effects of polymyxins?

Answer 9

Nephrotoxicity, neurotoxicity

Question 10

What are the adverse effects of daptomycin?

Answer 10

Myopathy and rhabdomyolysis

Question 11

What is the Jarisch-Herxheimer reaction?

Answer 11

Jarisch-Herxheimer reaction occurs when syphilis patients receive a natural penicillin and develop fever, chills, and start to hyperventilate BUT, it just means they are getting better! The body is mounting an immune response.

DO NOT STOP THE DRUG lol