Adults

Dosage varies widely based on the specific condition, severity, and patient response. Typically, for conditions requiring rapid effect, initial doses range from 10 mg to 80 mg intramuscularly once daily or every 1-2 weeks. For severe acute conditions, higher doses may be used intravenously.

Elderly

No specific dose adjustment is generally required, but caution is advised due to increased susceptibility to side effects. The lowest effective dose should be used.

Renal_impairment

No specific dosage adjustment is usually necessary for renal impairment, but caution is advised. Methylprednisolone is largely metabolized in the liver.

Onset

Onset of action is typically within 1 hour for IV administration of methylprednisolone sodium succinate, and within 6-48 hours for IM administration of methylprednisolone acetate, with peak effects after a few days.

Excretion

Excreted predominantly by the kidneys as inactive metabolites. Minimal amounts excreted in bile.

Half life

Plasma half-life: 2.4-3.5 hours. Biological half-life: 18-36 hours.

Absorption

Rapidly absorbed after intramuscular administration. Bioavailability varies depending on the salt form and route of administration.

Metabolism

Primarily hepatic metabolism, mainly via CYP3A4-mediated 6β-hydroxylation.

Anticoagulants (e.g., Warfarin)

Methylprednisolone may either potentiate or inhibit the effects of anticoagulants; careful monitoring of INR is required.

Diuretics (e.g., Thiazides, Loop diuretics)

May enhance potassium depletion.

NSAIDs (Nonsteroidal Anti-inflammatory Drugs)

Increased risk of gastrointestinal ulceration and bleeding when co-administered.

CYP3A4 Inducers (e.g., Rifampin, Phenytoin, Barbiturates)

May increase methylprednisolone clearance, reducing its plasma levels and therapeutic effects.

CYP3A4 Inhibitors (e.g., Ketoconazole, Macrolide antibiotics, Grapefruit juice)

May decrease methylprednisolone clearance, increasing its plasma levels and risk of side effects.