Lincomycin, a part of the lincosamide group of antibiotics is prescribed in oral as well as injectable forms for various infections of ENT origin, respiratory infections as well as dental infections. The following article highlights the usage, dosage and adverse effects of lincomycin in daily clinical practice.

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Lincomycin, the first antibiotic of the Lincosamide class, has been studied and used in several common outpatient and hospital-based infections, in both its oral and injectable forms. It is an antibiotic indicated only for the treatment of serious infections and is typically reserved for use in cases of penicillin allergy or where penicillin is inappropriate.

The clinical use of lincomycin has largely been superseded by its semisynthetic derivative clindamycin due to its higher efficacy and a wider range of susceptible organisms, though lincomycin remains in use. The drug was approved by the FDA in 1964. The drug is indicated for the treatment of serious bacterial infections by susceptible strains of streptococci, pneumococci, and staphylococci in patients who are allergic to penicillins or for situations in which penicillin is deemed inappropriate.

As with all antibacterial agents, lincomycin should only be used to treat infections proven or strongly suspected to be caused by susceptible bacteria. The main ones among these are ear nose throat (ENT) and respiratory tract infections (RTI), skin and soft tissue infections (SSTI) including surgical wound infections, bone and joint Infections (osteomyelitis and septic arthritis), and oro-dental infections.

Lincomycin inhibits bacterial protein synthesis by binding to the 23S RNA of the 50S subunit of the bacterial ribosome but has been found to be predominantly bacteriostatic in vitro. Cross-resistance has been demonstrated between clindamycin and lincomycin. Resistance is most often due to methylation of specific nucleotides in the 23S RNA of the 50S ribosomal subunit, which can determine cross-resistance to macrolides and streptogramins B (MLSB phenotype).

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Target organisms

Lincomycin has been shown to be active against most strains of the following bacteria both in vitro and in clinical infections:

1. Staphylococcus aureus
2. Streptococcus pneumoniae

Lincomycin has been shown to be active in vitro against the following microorganisms; however, the safety and efficacy of Lincocin in treating clinical infections due to these organisms have not been established in adequate and well-controlled trials.

1. Gram-positive bacteria

• Corynebacterium diphtheriae
• Streptococcus pyogenes
• Viridans group streptococci

2. Anaerobic bacteria

• Clostridium tetani
• Clostridium perfringens

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Dosage and administration

Intramuscular

Adults:

• Serious infections- 600 mg (2 ml) intramuscularly every 24 hours
• More severe infections- 600 mg (2 ml) intramuscularly every 12 hours or more often

Paediatric patients (over 1 month of age):

• Serious infections- One IM injection of 10 mg/kg (5 mg/lb) every 24 hours
• More severe infections- One IM injection of 10 mg/kg (5 mg/lb) every 12 hours or more often

Intravenous

Adults: The intravenous dose will be determined by the severity of the infection.

• For serious infections, doses of 600 mg of lincomycin (2 mL of LINCOCIN) to 1 gram are given every 8 to 12 hours
• For more severe infections, these doses may have to be increased
• In life-threatening situations, daily intravenous doses of as much as 8 grams have been given
• Intravenous doses are given on the basis of 1 gram of lincomycin diluted in not less than 100 mL of appropriate solution and infused over a period of not less than one hour

Pediatric patients (over 1 month of age): 10 to 20 mg/kg/day (5 to 10 mg/lb/day) depending on the severity of the infection may be infused in divided doses as described above for adults. Severe cardiopulmonary reactions have occurred when this drug has been given at greater than the recommended concentration and rate.

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Subconjunctival injection

0.25 mL (75 mg) injected subconjunctivally will result in ocular fluid concentrations of antibacterial (lasting for at least 5 hours) sufficient for most susceptible pathogens.

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Adverse effects

Clostridium difficile associated diarrhoea (CDAD)

1. CDAD has been reported with the use of nearly all antibacterial agents, including Lincomycin, and may range in severity from mild diarrhoea to fatal colitis.
2. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.
3. C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy.
4. CDAD must be considered in all patients who present with diarrhoea following antibacterial use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents.
5. If CDAD is suspected or confirmed, ongoing antibacterial use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated.

Hypersensitivity

1. Severe hypersensitivity reactions, including anaphylactic reactions and severe cutaneous adverse reactions (SCAR) such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), acute generalised exanthematous pustulosis (AGEP), and erythema multiforme (EM) have been reported in patients receiving Lincocin therapy.
2. If an anaphylactic reaction or severe skin reaction occurs, Lincocin should be discontinued and appropriate therapy should be initiated.

Benzyl alcohol toxicity in paediatric patients (gasping syndrome)

1. Most preparations of Lincomycin contain benzyl alcohol as a preservative.
2. Benzyl alcohol has been associated with serious adverse events, including the “gasping syndrome”, and death in pediatric patients.
3. Although normal therapeutic doses of this product ordinarily deliver amounts of benzyl alcohol that are substantially lower than those reported in association with the “gasping syndrome”, the minimum amount of benzyl alcohol at which toxicity may occur is not known.
4. The risk of benzyl alcohol toxicity depends on the quantity administered and the liver and kidneys’ capacity to detoxify the chemical. Premature and low-birth-weight infants may be more likely to develop toxicity.

Disclaimer: The content is for educational purpose only. For agent specific information, healthcare providers are requested to refer the updated prescribing information.