A CONCISE GUIDE FOR THE OPTIMAL USE OF POLYMYXINS
Glossary
Polymyxin E: colistin ,
Polymyxin B: Polymyxin B may be a suitable alternative to colistin with probably less sideeffects.
CMS/Colistimethate sodium/colistin methanesulfonate/colistin sulfomylmethate/
pentasodium colistimethanesulfate/: the prodrug of colistin, for parenteral and nebulized
use
Colistin sulfate: tablets, syrup, powder, for topical use and gut decontamination
Equivalence of colistin base and colistimethate sodium, expressed either as mg or
as IU (adapted from [1, 2])
Colistin Base
Activity/CBA) (mg)
1mg
150mg
30mg


Colistimethate
sodium/CMS (mg)
2.7mg
1mg
400mg
~80mg
Colistimethate sodium/
CMS (IU)
~30000 IU
~12500 IU
5MIU
1 MIU
Caution is required when using mg, to distinct between Colistin Base Activity or
Colistimethate Sodium: Danger of toxicity
Reporting of colistin doses in terms of milligrams of CMS is discouraged. Colistin doses
should be expressed in terms of the primary convention used in this region of the world
(ie, number of IU or milligrams of CBA)
1
Polymyxin B: The recommended dose for severe infections is 1.5-3 mg/kg/day. No
recommendation can be given about the need of a loading dose. For patients on
continuous renal replacement therapy, dosage adjustments are not necessary
Loading and maintenance dosing of colistin according to renal function status,
for a targeted peak blood level of 2μg/ml [3, 4]
Loading Dose
Body weight (Kg) divided by 7.5
Comments: i)maximum permitted dose 10 MIU
ii) ideal or real body weight in Kg choose the least
iii) not related to renal function status
Maintenance dose
Adjustment to renal function
[Clcr divided by 10] + 2 given in 2-3 doses
Haemodialysis
2 MIU in two daily doses
Additional 30% of the daily dose post dialysis
Continuous Haemofiltration
10-12 MIU in two or daily doses
Continuous ambulatory
peritoneal dialysis
5 MIU daily
Comments: i)The 1st maintenance dose should be given 24h post loading dose
ii) Clcr: creatinine clearance
iii) MIU: million international units
iv)For doses >10MIU special attention should be given to renal function
Nebulized colistin
500000IU bid- 2MIU tid
Comments: i) 2MIU tid are preferred over lower dosage regimens
ii) 5MIU tid have been also used without reported toxicity
iii) a vibrating mesh nebulizer is preferred
iv) probably co-administration of standard doses parenterally is necessary
Intrathecally or intraventricularly administered colistin
125000- 250000 once daily
Comments: i) the necessity of a loading dose is unknown
2
Administ
ration of
colistin
in the
site of
infection
ii) co-administration of standard doses parenterally is necessary
iii) 500000IU once daily has been reported with good tolerance
References
1.Poulakou G, Bassetti M, Righi E, Dimopoulos G (2014) Current and future treatment options for
infections caused by multidrug-resistant Gram-negative pathogens. Future Microbiol 9:1053-1069
2. Nation RL, Li J, Cars O, Couet W, Dudley MN, Kaye KS, Mouton JW, Paterson DL, Tam VH,
Theuretzbacher U, Tsuji BT, Turnidge JD (2014) Consistent global approach on reporting of colistin
doses to promote safe and effective use. Clin Infect Dis 58:139-141.
3. Garonzik SM, Li J, Thamlikitkul V, Paterson DL, Shoham S, Jacob J, Silveira FP, Forrest A, Nation RL
(2011) Population pharmacokinetics of colistin methanesulfonate and formed colistin in critically ill
patients from a multicenter study provide dosing suggestions for various categories of patients.
Antimicrob Agents Chemother 55: 3284–3294
4. Koomanachai P, Landersdorfer CB, Chen G, Lee HJ, Jitmuang A, Wasuwattakul S, Sritippayawan S,
Li J, Nation RL, Thamlikitkul V (2014) Pharmacokinetics of colistin methanesulfonate and formed
colistin in end-stage renal disease patients receiving continuous ambulatory peritoneal dialysis.
Antimicrob Agents Chemother 58:440-446
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