Drug reference

Polymyxin B

Polymyxin (cyclic cationic polypeptide) antibiotic · Antibiotic

Also known as Polymyxin B sulfate, Aerosporin

START

IV 15,000–25,000 units/kg/day in 2 divided doses (consider loading in critical illness)

TYPICAL MAX

~25,000 units/kg/day (normal renal function)

STOP IF

Progressive AKI or neuromuscular blockade/respiratory weakness

WATCH

Daily renal function, neurotoxic symptoms, concurrent nephro/neurotoxins

CDSCO approvedSchedule HATC J01XB02

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 30min · IV onset
PEAK: 1h · end of infusion
t½: 6h · plasma t½
DURATION: 12h · q12h interval

EXCRETION

Primarily renal; slow tubular elimination

route + CYP

INTERACTIONS

12 major

SEVERE in our sources

PREGNANCY

Use only for life-threatening MDR infection when no alternative — limited data

FDA category + note

Top interactionssee all 12 →

AmikacinSevereDatabaseDDInter
AtracuriumSevereDatabaseDDInter
Botulinum Toxin Type ASevereDatabaseDDInter
Botulinum Toxin Type BSevereDatabaseDDInter

Available in India

33 branded formulations and 22 fixed-dose combinations. Look up specific brands in the Drugs workspace.

Mechanism

Cationic detergent-like binding to lipid A of Gram-negative LPS, disrupting outer and cytoplasmic membrane permeability → cell death; also endotoxin sequestration.

Indications

Serious infections by MDR Gram-negative bacilli (Pseudomonas, Acinetobacter, Klebsiella) when alternatives unsuitableTopical/ophthalmic/otic Gram-negative infections (combination products)

Dosing

Adult: IV: 15,000–25,000 units/kg/day in 2 divided doses (≈1.5–2.5 mg/kg/day; 10,000 units ≈ 1 mg). Loading dose used in critically ill per specialist guidance.
Pediatric: 15,000–40,000 units/kg/day divided (specialist).
Renal adjustment: Renally cleared — reduce dose/extend interval per CrCl; specialist/TDM where available.
Hepatic adjustment: No specific adjustment.
Geriatric: Reduced renal function — adjust dose, monitor closely.
Max dose: ~25,000 units/kg/day (normal renal function)

Pharmacokinetics

Onset

IV immediate

Peak effect

End of infusion

Duration

Dose-interval (q12h)

Half-life

~6 h (prolonged in renal impairment)

Bioavailability

Negligible oral; 100% IV

Protein binding

Moderate

Metabolism

Minimal

Excretion

Primarily renal (slow tubular handling)

Contraindications

Hypersensitivity to polymyxins
Caution (relative): significant renal impairment, concurrent nephro/neurotoxins, myasthenia gravis

Side effects

Common

Nephrotoxicity (dose-related, often reversible)Neurotoxicity: paraesthesia, dizziness, ataxiaInfusion-related reactionsInjection-site pain

Serious

Acute kidney injury
Neuromuscular blockade/respiratory paralysis (esp. with anaesthetics/relaxants)
Severe hypersensitivity

Pregnancy & lactation

Pregnancy

Use only for life-threatening MDR infection when no alternative — limited data

Lactation

Limited data; minimal oral absorption by infant — caution

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.

Source: DDInter

Atracurium

Severe

Database

Clinical effect not specified

Source: DDInter

Botulinum Toxin Type A

Severe

Database

Clinical effect not specified

Source: DDInter

Botulinum Toxin Type B

Severe

Database

Clinical effect not specified

Source: DDInter

Cidofovir

Severe

Database

Clinical effect not specified

Source: DDInter

Cisatracurium

Severe

Database

Clinical effect not specified

Source: DDInter

Colistimethate Sodium

Severe

Database

Significantly increased risk of acute kidney injury, respiratory depression, and other neurotoxic effects due to the similar toxicity profiles of these two polymyxin antibiotics.

Concomitant use is generally contraindicated due to the high risk of severe toxicity. If there is an absolute clinical necessity (e.g., pan-drug resistant infection with no other options), extreme caution, intensive monitoring of renal function, respiratory status, and neuromuscular function is required. This would be an exceptional circumstance.

Colistin Sulphate

Severe

Database

Significantly increased risk of acute kidney injury and neurotoxic effects (e.g., paresthesia, dizziness, neuromuscular blockade) due to the similar toxicity profiles of these related drugs.

Avoid concomitant use due to the high risk of severe toxicity. These drugs are generally not used together systemically.

Deferasirox

Severe

Database

Clinical effect not specified

Source: DDInter

Diatrizoate

Severe

Database

Clinical effect not specified

Source: DDInter

Doxacurium