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|Chloramphenicol

Chloramphenicol

Trade Names:
Chloromycetin Sodium Succinate
- Powder for Injection 100 mg/mL (as base) when reconstituted

Mechanism of Action

Pharmacology

Interferes with or inhibits microbial protein synthesis.

Pharmacokinetics

Absorption

Chloramphenicol is rapidly absorbed and 75% to 90% bioavailable. C _max is 11.2 mcg/mL. T _max is 1 hr. Therapeutic concentrations are 10 to 20 mcg/mL (peak) and 5 to 10 mcg/mL (trough).

Distribution

Chloramphenicol diffuses rapidly; highest concentrations are found in the liver and kidney and lowest concentrations are found in the brain and CSF. It also is found in pleural and ascitic fluid, saliva, milk, and aqueous and vitreous humors. It crosses the placenta and is about 60% protein bound.

Metabolism

Chloramphenicol or sodium succinate is hydrolyzed to active chloramphenicol base.

Elimination

68% to 99% is excreted in the urine. 8% to 12% is excreted as free chloramphenicol; the remainder is excreted as inactive metabolites. Small amounts are found in bile and feces. The t _½ is about 1.5 to 4 hr.

Special Populations

Metabolism and excretion may be reduced. Dosage adjustment is recommended.

Metabolism and excretion may be reduced. Dosage adjustment is recommended.

Indications and Usage

Treatment of infections caused by susceptible strains of specific microorganisms; serious systemic infections for which less potentially dangerous drugs are ineffective or contraindicated.

Contraindications

Trivial infections (eg, colds, influenza, throat infections) or infections other than indicated; prophylaxis of systemic bacterial infections; hypersensitivity to product.

Dosage and Administration

IV 50 mg/kg/day in divided doses q 6 hr; may require up to 100 mg/kg/day initially for infections caused by moderately resistant organisms.

IV 50 mg/kg/day in 4 doses q 6 hr; 50 to 100 mg/kg/day for severe infections (eg, bacteremia, meningitis).

IV 25 mg/kg/day.

IV Usually 25 mg/kg/day in 4 doses q 6 hr.

IV up to 50 mg/kg/day in 4 doses q 6 hr.

IV 25 mg/kg qd.

General Advice

• For IV use only; it is less effective when given via IM route.
• Give direct IV as 10% solution in water for injection or 5% dextrose injection over at least 1 min. Do not administer if cloudy.

Storage/Stability

Store reconstituted solution below 30°C (86°F). Prior to reconstitution, refrigerate at 2° to 8°C (36° to 46°F). Protect from light. Remove from refrigerator for dispensing; discard after 21 days.

Drug Interactions

Risk or severity of bone marrow suppression may be increased.

May enhance anticoagulation action.

May reduce effectiveness of chloramphenicol while barbiturate effects may be enhanced; effects may last days after barbiturates are withdrawn.

May increase serum iron levels.

May increase serum hydantoin levels, with possible toxicity; chloramphenicol levels may increase or decrease.

May reduce chloramphenicol serum levels; effect may last days after rifampin is withdrawn.

May cause clinical manifestations of hypoglycemia.

May decrease hematologic effects of vitamin B ₁₂ in patients with pernicious anemia.

Laboratory Test Interactions

None well documented.

Adverse Reactions

CNS

Headache; mental confusion; delirium; mild depression; optic neuritis; peripheral neuritis.

GI

Diarrhea; nausea; vomiting; glossitis; stomatitis; enterocolitis.

Hematologic

Bone marrow depression; aplastic anemia; hypoplastic anemia; thrombocytopenia; granulocytopenia.

Miscellaneous

Hypersensitivity reactions (eg, fever, rash, angioedema, urticaria, anaphylaxis); Gray syndrome.

Precautions

Pregnancy

Category C .

Lactation

Excreted in breast milk.

Children

Use drug with caution and in reduced dosages in premature and term infants and children with immature metabolic functions to avoid Gray syndrome toxicity (eg, toxic and potentially fatal reaction in premature infants and newborns). Symptoms of Gray syndrome generally appear in this sequence: abdominal distention with or without emesis; progressive pallid cyanosis; vasomotor collapse, frequently accompanied by irregular respiration; death within a few hours of onset (death occurs in 40% of patients within 2 days of initial symptoms). Other initial symptoms of Gray syndrome may include refusal to suck, loose green stools, flaccidity, ashen gray color, decreased temperature, and refractory lactic acidosis.

Renal Function

Excessive blood levels of drug may occur; dosage adjustment may be required.

Hepatic Function

Excessive blood levels of drug may occur; dosage adjustment may be required. Pre-existing liver dysfunction may be significant risk factor for Gray syndrome.

Special Risk Patients

Use drug with caution in patients with acute intermittent porphyria or G-6-PD deficiency.

Superinfection

Use of antibiotics may result in bacterial or fungal overgrowth.

Blood dyscrasias

Serious and fatal blood dyscrasias can occur.

Overdosage

Symptoms

Nausea, vomiting, unpleasant taste, diarrhea, bone marrow suppression.

Patient Information

• Emphasize importance of follow-up examinations because of possible complications from drug that can occur up to months after therapy is completed.
• Instruct patient that bitter taste that occurs after IV administration will subside 2 to 3 min after injection.
• Instruct patient to report these symptoms to health care provider: bleeding, fever, sore throat, itching, nausea, vomiting, diarrhea, bruising, numbness, weakness of hands or feet.
• Advise parents to report these symptoms to health care provider if they occur in infants: failure to feed, abdominal distention, drowsiness, blue or gray skin color, any problems in breathing.
• Instruct patient to report signs of further infection or worsening of current infection to health care provider.