Adults

Dosage varies widely based on the specific condition, its severity, and patient response. Intramuscularly: 40-120 mg every 1-4 weeks. Intra-articular/soft tissue: 4-80 mg, depending on the size of the joint or lesion and the severity of the condition, typically repeated every 1-5 weeks. Not for IV use.

Elderly

No specific dose adjustments are typically required based on age alone, but elderly patients should be monitored more closely for potential side effects, particularly bone density and blood pressure.

Renal_impairment

No specific dose adjustments are generally required for patients with renal impairment, as methylprednisolone is primarily metabolized in the liver.

Onset

Anti-inflammatory effects can begin within hours of administration, with sustained action over several days to weeks depending on the route and dose.

Excretion

Mainly excreted in the urine as inactive metabolites. A small amount is excreted unchanged.

Half life

Plasma elimination half-life is approximately 2.5-3.5 hours, but the biological half-life at the tissue level is much longer (18-36 hours) due to its sustained release and tissue binding.

Absorption

Slowly absorbed from the injection site (intramuscular or intra-articular). Peak plasma levels typically achieved within 4-8 hours after intramuscular injection.

Metabolism

Primarily metabolized in the liver by the cytochrome P450 enzyme system, predominantly CYP3A4. Metabolites are mostly inactive.

Anticoagulants (e.g., warfarin)

Corticosteroids may alter the effects of anticoagulants; close monitoring of INR is recommended.

Diuretics (e.g., thiazides, loop diuretics)

Increased risk of hypokalemia (potassium loss).

NSAIDs (Nonsteroidal Anti-inflammatory Drugs)

Concomitant use may increase the risk of gastrointestinal ulceration and bleeding.

Antidiabetic agents (e.g., insulin, oral hypoglycemics)

Corticosteroids may increase blood glucose levels, requiring adjustment of antidiabetic medication dosage.

CYP3A4 inducers (e.g., rifampin, phenobarbital, phenytoin)

May decrease methylprednisolone plasma concentrations, reducing its therapeutic effect.

CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, grapefruit juice)

May significantly increase methylprednisolone plasma concentrations, leading to increased effects and side effects.