Lincomycin hydrochloride hydrate

Lincomycin hydrochloride hydrate More Info

Lincomycin Hydrochloride Hydrate is a water-soluble antibacterial agent of the lincosamide class, widely used in clinical and veterinary medicine for its broad-spectrum activity against gram-positive bacteria and some anaerobic pathogens. It is the hydrated hydrochloride salt form of lincomycin, optimized for solubility and bioavailability compared to the free base form.

Chemical & Physical Properties

Molecular Formula: Typically C18​H34​N2​O6​S ⋅ HCl ⋅ xH2​O (the common hydrated form is monohydrate, C18​H34​N2​O6​S ⋅ HCl ⋅ H2​O)

Molecular Weight: 461.01 (monohydrate)

Appearance: White to off-white crystalline powder

Solubility: Freely soluble in water and methanol, slightly soluble in ethanol, insoluble in non-polar organic solvents (e.g., ether, benzene)

Stability: Stable under normal storage conditions (sealed, dry, cool place); susceptible to degradation in extreme pH or high temperature.

Mechanism of Action

It exerts antibacterial effects by inhibiting bacterial protein synthesis: it binds reversibly to the 50S subunit of the bacterial ribosome, blocking the transpeptidation step of peptide chain elongation, thus preventing the formation of bacterial proteins and inhibiting bacterial growth and reproduction.

It is bacteriostatic at low concentrations and may exhibit bactericidal activity at high concentrations against susceptible strains.

Antibacterial Spectrum

Active primarily against gram-positive aerobic and anaerobic bacteria; little to no activity against gram-negative bacteria (due to poor penetration of the gram-negative outer membrane):

Gram-positive aerobes: Staphylococcus aureus (including penicillinase-producing strains), Streptococcus pyogenes, Streptococcus pneumoniae, Bacillus anthracis

Anaerobes: Clostridium perfringens, Clostridium tetani, Bacteroides fragilis, Peptostreptococcus species

Other: Mycoplasma species (effective for some mycoplasmal infections)

Pharmacokinetics

Absorption: Rapidly absorbed after oral administration, with peak plasma concentrations reached in 1–2 hours; intramuscular injection has higher bioavailability (~90%) than oral administration (~20–35%). Food may delay oral absorption but does not affect total bioavailability.

Distribution: Widely distributed in body tissues and fluids (e.g., muscle, bone, soft tissue, synovial fluid); high concentrations accumulate in bone and bone marrow (a key advantage for bone infections). It crosses the placental barrier and is excreted in breast milk.

Metabolism: Partially metabolized in the liver to inactive metabolites.

Elimination: Excreted primarily via the kidneys (30–60% as unchanged drug in urine) and bile (10–20%); the elimination half-life is 4–6 hours in normal renal function, prolonged in patients with renal impairment.

Clinical Applications

Used for the treatment of infections caused by susceptible bacterial strains, mainly for mild to moderate infections (second-line agent for many cases, reserved when penicillins/cephalosporins are contraindicated or ineffective):

Bone and joint infections: Osteomyelitis, septic arthritis (especially caused by Staphylococcus aureus)

Skin and soft tissue infections: Cellulitis, abscesses, wound infections

Respiratory tract infections: Pneumonia, bronchitis, empyema (caused by susceptible gram-positive bacteria/anaerobes)

Intra-abdominal and pelvic infections: Peritonitis, pelvic inflammatory disease (anaerobic component)

Other: Septicemia, endocarditis (in combination with other agents), and veterinary infections (e.g., bovine mastitis, swine respiratory diseases)

Dosage Forms

Oral: Capsules, oral solution/syrup

Parenteral: Injectable solution (for intramuscular or intravenous administration)

Topical: Ointments (for local skin infections, limited use)

Adverse Reactions

Generally well-tolerated; adverse effects are mild to moderate and reversible:

Gastrointestinal (most common): Nausea, vomiting, diarrhea, abdominal pain; rare but severe: pseudomembranous colitis (caused by Clostridioides difficile overgrowth, may occur even after treatment cessation)

Hematologic: Transient leukopenia, neutropenia, thrombocytopenia (rare, with long-term use)

Hepatic: Mild elevation of liver enzymes (ALT/AST); rare severe hepatotoxicity

Local reactions: Pain, induration at intramuscular injection site; phlebitis with intravenous administration

Allergic reactions: Rash, pruritus, urticaria (rare anaphylaxis)

Other: Dizziness, headache, tinnitus (rare)

Contraindications & Precautions

Contraindications: Hypersensitivity to lincomycin, clindamycin (cross-sensitivity exists) or any component of the formulation.

Precautions:

Use cautiously in patients with renal/hepatic impairment (dosage adjustment required)

Avoid prolonged use (risk of superinfection or pseudomembranous colitis)

Discontinue immediately and treat if severe diarrhea occurs (avoid antiperistaltic drugs like loperamide)

Pregnancy/Lactation: Use only when the benefit outweighs risk; breastfeeding is not recommended during treatment

Pediatric/Geriatric: Adjust dosage based on age, weight and renal function; monitor geriatric patients for adverse effects

No direct activity against gram-negative bacteria; avoid monotherapy for mixed gram-positive/gram-negative infections (combine with a gram-negative active agent)

Drug Interactions

Synergism: Combined with aminoglycosides (e.g., gentamicin) for severe gram-positive infections (e.g., endocarditis, osteomyelitis)

Antagonism: Avoid combined use with macrolides (e.g., erythromycin) or chloramphenicol (bind to the same ribosomal subunit, competitive inhibition)

Increased risk of neuromuscular blockade: Combined with muscle relaxants (e.g., succinylcholine), aminoglycosides or general anesthetics (may cause respiratory depression)

Increased serum concentration: Probenecid inhibits renal excretion of lincomycin, increasing its plasma levels and half-life

Storage & Handling

Store sealed in a dry, cool place (2–8°C for injectable forms; room temperature 15–30°C for oral forms)

Protect from light and moisture

Do not use if the solution is turbid or contains precipitates (for injectable forms)

Keep out of reach of children

Key Note

Clindamycin (a derivative of lincomycin) has broader antibacterial activity (especially against anaerobes) and better oral absorption, so it is more commonly used in clinical practice today. Lincomycin hydrochloride hydrate is mainly reserved for patients who cannot tolerate clindamycin or in veterinary medicine.