Dosing and uses of Colistimethate sodium, Coly Mycin M (colistin)
Adult dosage forms and strengths
powder for injection
- 150mg/vial
Susceptible Infections
Dosage expressed in terms of colistin base
2.5-5 mg/kg/day divided q6-12hr IV/IM; not to exceed 5 mg/kg/day
Renal Impairment
CrCl >80 mL/min: No dosage adjustment required
CrCl 50-79 mL/min: 2.5-3.8 mg/kg/day IV/IM divided q12hr
CrCl 30-49 mL/min: 2.5 mg/kg/day IV/IM qDay or divided q12hr
CrCl 10-29 mL/min: 1.5 mg/kg IV/IM q36hr
Other Indications & Uses
Gram-neg. infection (e.g., Enterobacter aerogenes, E. coli, Klebsiella, Pseudomonas) unresponsive to other antibiotics
Multi-drug resistant gram-neg. infection
Pediatric dosage forms and strengths
powder for injection
- 150 mg/vial
Susceptible Infections
Dosage expressed in terms of colistin bas
<12 years old: Safety and efficacy not established
Colistimethate sodium, Coly Mycin M (colistin) adverse (side) effects
1-10%
Dizziness
Paresthesia, tingling sensation
<1%
Neurotoxicity
Nephrotoxicity
Acute respiratory failure (inhalation route)
Respiratory tract paralysis
Warnings
Contraindications
Hypersensitivity
Caution
Do not exceed 5 mg/kg/day (as colistin base) with normal renal function (see Dosing for renal impairment)
Not indicated for infections by Proteus or Neisseria (most strains are resistant)
Risk of nephrotoxicity, neurotoxicity; discontinue if elevated BUN/creatinine
Risk of respiratory arrest in myasthenia gravis or concomitant anesthetics or neuromuscular blocking drugs
Risk of C. difficile-associated pseudomembranous colitis
Sedative effects may impair driving, operating machinery
Pregnancy and lactation
Pregnancy category: C
Lactation: unknown; use caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Colistimethate sodium, Coly Mycin M (colistin)
Half-Life
Normal renal function: 2-3hr
CrCl < 20 mL/min: 10-20 hr
Peak Plasma
IV: 10 min
Time: 2 hr (IM)
Concentration: 5-7.5 mcg/mL (IM); higher IV
Other Information
Protein Bound: 50%
Metabolism: colistimethate sodium hydrolyzed in vivo
Metabolites: colistin (active)
Excretion: urine
Dialyzable: unknown
Mechanism of action
Structurally similar to polymyxin B; colistimethate hydrolyzed to colistin in vitro or in vivo
Cationic detergent that damages bacterial cytoplasmic membrane, causing cell death
Administration
IV Incompatibilities
Additive: erythromycin, hydrocortisone Na-succinate, kanamycin, cefazolin
IV Compatibilities
Additive: amikacin, ascorbic acid, chlormaphenicol, diphenhydramine, heparin, penicillin G Na/K, phenobarbital, polymyxin B, ranitidine, vit B/C
Syringe: ampicillin, penicillin G Na
IV Preparation
Reconstitute with 2 mL SWI to obtain a 75 mg/mL solution
IV/IM Administration
IM or
IV push: half of daily dose injected over 3-5 min q12 hr
IV infusion: half of daily dose injected over 3-5 min; other half mixed with compatible IV solution and administered 1-2 hr later at 5-6 mg/hr