Ceftriaxone exhibits excellent bioavailability following intramuscular or intravenous administration. After a single intramuscular dose, peak serum concentrations are typically achieved within 1-3 hours.
Intravenous administration provides rapid distribution, with high concentrations observed in various tissues and fluids, including lung, gallbladder, and cerebrospinal fluid (CSF). CSF penetration is particularly noteworthy, making it a valuable option for treating meningitis.
The drug’s extensive protein binding (approximately 95%) influences its distribution and half-life. This binding, primarily to albumin, means a relatively large volume of distribution.
Ceftriaxone’s elimination is primarily through biliary excretion, with minimal renal clearance. This characteristic is crucial for patients with renal impairment; dosage adjustment is typically not required.
The elimination half-life is approximately 6-8 hours in adults, with slightly longer durations observed in neonates and the elderly. This necessitates once-daily dosing for many indications.
Metabolism of ceftriaxone is limited, primarily involving non-enzymatic hydrolysis. This reduces the potential for drug interactions via metabolic pathways.
Consider these pharmacokinetic properties when determining appropriate dosing regimens and managing potential interactions. Consult current prescribing information for specific recommendations.
