Drug reference

Colistin

Polymyxin antibiotic (lipopeptide) · Antibiotic

Also known as Colistimethate sodium, Colistin sulfate, Polymyxin E, CMS

START

Loading dose recommended (9 MIU CMS); check baseline creatinine and calculate eGFR; assess for concurrent nephrotoxins; reserve for MDR Gram-negative infections

TYPICAL MAX

5 mg/kg/day CBA equivalent

STOP IF

eGFR decline >50% from baseline, severe neurotoxicity, therapeutic alternatives become available, treatment course complete (usually 7-14 days)

WATCH

Serum creatinine and eGFR daily (nephrotoxicity), neuro symptoms (paresthesia, weakness), drug levels if available (target Cmax 2-4 mcg/mL), concurrent nephrotoxins

CDSCO approvedSchedule HATC J01XB01

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 2h · Rapid bactericidal onset
PEAK: 2h · CMS peak (prodrug)
t½: 14.4h · Colistin half-life
DURATION: 12h · 8-12 hour dosing interval

EXCRETION

Renal (majority)

route + CYP

INTERACTIONS

5 major

SEVERE in our sources

PREGNANCY

Avoid in pregnancy if alternatives available; limited data - animal studies show fetal toxicity at high doses

FDA category + note

Top interactionssee all 6 →

AmikacinSevereDatabase
AminoglycosidesSevereDatabaseKimi deep-research + Cla
Amphotericin BSevereDatabaseKimi deep-research + Cla
Neuromuscular Blocking AgentsSevereDatabaseKimi deep-research + Cla

Available in India

251 branded formulations. Look up specific brands in the Drugs workspace.

Mechanism

Cationic lipopeptide that binds to negatively charged phosphate groups on lipopolysaccharide (LPS) and phospholipids in the outer membrane of Gram-negative bacteria, disrupting membrane integrity and increasing permeability. Bactericidal action via cell lysis. Effective against most Gram-negative bacilli including Pseudomonas, Acinetobacter, and Enterobacterales.

Indications

Serious infections caused by multidrug-resistant (MDR) Gram-negative bacilli (carbapenem-resistant Enterobacterales, MDR Pseudomonas, MDR Acinetobacter)Hospital-acquired / ventilator-associated pneumonia (HAP/VAP) due to MDR Gram-negativesComplicated intra-abdominal infections (MDR)Adjunctive therapy for cystic fibrosis (inhaled colistimethate)

Dosing

Adult: IV: 2.5-5 mg/kg/day (colistin base activity, CBA) in 2-3 divided doses OR 9 MIU loading then 4.5 MIU q12h (colistimethate sodium, CMS). Inhaled: 1-2 MIU q8h via nebulizer
Pediatric: IV: 2-5 mg/kg/day CBA in 2-3 divided doses. Limited safety data in children
Renal adjustment: Essential - see renal zones. Colistin is significantly renally cleared
Hepatic adjustment: No adjustment needed; not hepatically metabolized
Geriatric: Start at lower dose; monitor renal function and neurotoxicity closely
Max dose: 5 mg/kg/day CBA (IV); 6 MIU/day inhaled

Pharmacokinetics

Onset

Rapid bactericidal effect

Peak effect

CMS (prodrug): 1-2 hours; Colistin: gradual accumulation over 24-48 hours

Duration

8-12 hours

Half-life

CMS: 2-3 hours; Colistin: 14.4 hours

Bioavailability

PO: <1%; IV: 100%; Inhaled: variable (10-40% systemic absorption)

Protein binding

Colistin: ~50%; CMS: minimal

Metabolism

CMS hydrolyzed to active colistin in plasma (slow conversion)

Excretion

Renal (majority, primarily as CMS and colistin)

Contraindications

Hypersensitivity to colistin
Myasthenia gravis (may worsen neuromuscular blockade)

Side effects

Common

Nephrotoxicity (20-60% - dose-dependent and reversible)Neurotoxicity (7-27%): paresthesia, dizziness, vertigoNauseaRash

Serious

Acute kidney injury (AKI) - most common dose-limiting toxicity
Neuromuscular blockade / apnea (especially with anesthesia or other NMB agents)
Respiratory arrest (rare, with rapid IV push)
Bronchospasm (inhaled form)
Severe allergic reactions

Pregnancy & lactation

Pregnancy

Avoid in pregnancy if alternatives available; limited data - animal studies show fetal toxicity at high doses

Lactation

Excretion in breast milk unknown; use with caution during breastfeeding

Drug interactions

Amikacin

Severe

Database

Increased risk of acute kidney injury and respiratory depression/paralysis

Avoid concomitant use due to high risk of toxicity. If no other options, monitor renal function and respiratory status extremely closely. Be prepared for respiratory support.

Aminoglycosides

Severe

Database

Additive nephrotoxicity and neuromuscular blockade

Avoid if possible; if unavoidable, monitor renal function and neuro status very closely

Source: Kimi deep-research + Cla

Amphotericin B

Severe

Database

Additive nephrotoxicity

Avoid concurrent use if possible; monitor renal function closely

Source: Kimi deep-research + Cla