Pharmacology for Anaesthesia and Intensive Care

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22 Antimicrobials

Side effects


Renal – nephrotoxicity is rare but is usually seen with concurrent administration

of aminoglycosides or with pre-existing renal impairment. It usually resolves on

withdrawal of vancomycin.


Ototoxicity – very rare and usually associated with pre-existing hearing loss,

renal impairment or concomitant treatment with another ototoxic drug. It is very

uncommon if peak levels do not exceed 50 mg.l−^1 and exceedingly rare if they do

not exceed 30 mg.l−^1.


Phlebitis – the intravenous preparation should be diluted when given peripherally.


Histamine release – if administered too rapidly histamine release may cause

hypotension, tachycardia and a widespread rash (known as the ‘red man syn-

drome’). Administration should not exceed 10 mg.min−^1.


Haematological – neutropenia and thrombocytopenia are rare and reversible.

Teicoplanin

Teicoplanin is a similar antibiotic to vancomycin but with a longer duration of action

and 2–4 times the potency, allowing once daily administration. The preparation con-

tains two components A 1 (a phosphoglycolipid) and A 2 (a complex of 5 glycopep-

tides). Resistance to teicoplanin is more common with up to 25% ofStaph. epider-

midisshowing intermediate sensitivity.

Kinetics

Teicoplanin is not absorbed when given orally but can be given by intramuscular

injection. It is 90% protein bound and has better distribution than vancomycin. Bone

and CSF penetration are more reliable than with vancomycin but urine penetration is

less. It is given twice daily for 48 hours to facilitate loading, then once daily thereafter

(prolonged elimination half-life). In patients on CVVHDF the maintenance interval

should be increased to once every 48 hours.

Side effects

Teicoplanin is better tolerated than vancomycin but side effects do include rash,

eosinophilia, thrombocytopenia and fever. It has been used safely in patients known

to exhibit red man syndrome after vancomycin.

Lincosamides

Clindamycin

Parenteral clindamycin phosphate is a semi-synthetic derivative that is highly active

against gram-positive aerobes but demonstrates little activity against any gram-

negative aerobic organisms. Anaerobic organisms are highly susceptible. It is notably

active against a significant proportion of MRSA and covers Toxoplasma andPlasmod-

ium falciparum(but notPlasmodium vivax).