COLISTIMETHATE SODIUM

COLISTIMETHATE SODIUM
(koe-lis-ti-meth'ate)
Coly-Mycin M
Classifications: urinary tract antiinfective; antibiotic;
Therapeutic: antibiotic
Prototype: Trimethoprim
Pregnancy Category: B

Availability

150 mg injection

Action

Similar to polymyxin B but about one-third to one-fifth as potent. Antibacterial activity and overall toxicity are less, but nephrotoxic potential is equivalent to polymyxin B. Believed to act by affecting phospholipid component in bacterial cytoplasmic membranes with resulting damage and leakage of essential intracellular components.

Therapeutic Effect

Bactericidal against most gram-negative organisms, but not effective against Proteus or Neisseria species.

Uses

Particularly for severe, acute and chronic UTIs caused by susceptible strains of gram-negative organisms resistant to other antibiotics. Has been used with carbenicillin for Pseudomonas sepsis in children with acute leukopenia.

Contraindications

Hypersensitivity to polypeptide antibiotics; concomitant use of drugs that potentiate neuromuscular blocking effect (aminoglycoside antibiotics, other polymyxins, anticholinesterases, curariform muscle relaxants, ether, sodium citrate); nephrotoxic and ototoxic drugs; pregnancy (category B).

Cautious Use

Impaired renal function; myasthenia gravis; older adult patients, infants; lactation.

Route & Dosage

Urinary Tract Infections
Adult/Child: IM/IV 2.5–5 mg/kg/d divided in 2–4 doses, max of 5 mg/kg/d

Renal Impairment
S_cr 1.3–1.5 mg/dL: 2.5–3.8 mg/kg/d in 2 divided doses; 1.6–2.5 mg/dL: 2.5 mg/kg/d in a single dose or 2 divided doses; 2.6–4 mg/dL: 1.5 mg/kg q36h

Administration

Intramuscular

Reconstitute each 150-mg vial with 2 mL of sterile water for injection to yield a concentration of 75 mg/mL. Swirl vial gently during reconstitution to avoid bubble formation. IM injection should be made deep into upper outer quadrant of buttock. Patients commonly experience pain at injection site. Rotate sites.

Intravenous

PREPARE: Direct/Intermittent: Prepare first half of total daily dose as directed for IM then further dilute with 20 mL sterile water for injection. Prepare second half of total daily dose by diluting further in 50 mL or more of D5W, NS, D5/NS, RL or other compatible solution. IV infusion solution should be freshly prepared and used within 24 h.

ADMINISTER: Direct/Intermittent: First half of total daily dose: Give slowly over 3–5 min. Second half of total daily dose: Starting 1–2 h after the first half dose has been given, infuse the second half dose over the next 22–23 h.

INCOMPATIBILITIES Solution/additive: Cefazolin, cephapirin, erythromycin, hydrocortisone, hydroxyzine, kanamycin.

Reconstituted solution may be stored in refrigerator at 2°–8° C (36°–46° F) or at controlled room temperature of 15°–30° C (59°–86° F). Use within 7 d. Store unopened vials at controlled room temperature.

Adverse Effects (≥1%)

Body as a Whole: Drug fever, pain at IM site. GI: GI disturbances. CNS: Circumoral, lingual, and peripheral paresthesias; visual and speech disturbances, neuromuscular blockade (generalized muscle weakness, dyspnea, respiratory depression or paralysis), seizures, psychosis. Respiratory: Respiratory arrest after IM injection. Skin: Pruritus, urticaria, dermatoses. Special Senses: Ototoxicity. Urogenital: Nephrotoxicity.

Interactions

Drug: Tubocurarine, pancuronium, atracurium, aminoglycosides may compound and prolong respiratory depression; aminoglycosides, amphotericin B, vancomycin augment nephrotoxicity.

Pharmacokinetics

Peak: 1–2 h IM. Duration: 8–12 h. Distribution: Widely distributed in most tissues except CNS; crosses placenta; distributed into breast milk in low concentrations. Metabolism: In liver. Elimination: 66–75% in urine within 24 h. Half-Life: 2–3 h.

Nursing Implications

Assessment & Drug Effects

Lab tests: Culture and susceptibility tests should be performed initially and periodically during therapy to determine responsiveness of causative organisms. Baseline renal function tests should be performed prior to therapy; frequent monitoring of renal function and urine drug levels is advisable during therapy. Impaired renal function increases the possibility of nephrotoxicity, apnea, and neuromuscular blockade.
Report restlessness or dyspnea promptly. Respiratory arrest has been reported after IM administration.
Monitor I&O ratio and patterns: Decrease in urine output or change in I&O ratio and rising BUN, serum creatinine, and serum drug levels (without dosage increase) are indications of renal toxicity. If they occur, withhold drug and report to physician.
Close monitoring of older adult patients and infants is essential. They are particularly prone to renal toxicity because they tend to have inadequate renal reserves.
Be alert to neurologic symptoms: changes in speech and hearing, visual changes, drowsiness, dizziness, ataxia, and transient paresthesias, and keep physician informed.
Monitor closely postoperative patients who have received curariform muscle relaxants, ether, or sodium citrate for signs of neuromuscular blockade (delayed recovery, muscle weakness, depressed respiration).

Patient & Family Education

Avoid operating a vehicle or other potentially hazardous activities while on drug therapy because of the possibility of transient neurologic disturbances.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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