Generic Name

Medrol

Brand Names

for *methylprednisolone acetate*, a synthetic glucocorticoid.

Mechanism

Medrol is the brand name for *methylprednisolone acetate*, a synthetic glucocorticoid.
• Binds intracellular glucocorticoid receptors → translocates to the nucleus → alters transcription of anti‑inflammatory genes.
• ↓ Production of pro‑inflammatory cytokines (IL‑1, IL‑6, TNF‑α).
• ↑ Expression of anti‑inflammatory proteins (annexin‑1, lipocortin).
• Suppresses leukocyte migration, stabilizes lysosomal membranes, and reduces edema.

Pharmacokinetics

• Absorption: Oral bioavailability ≈ 93 %; intramuscular or intravenous forms bypass first‑pass metabolism.
• Distribution: Widely distributed, highly protein‑bound (~90 % to α‑1‑acid glycoprotein).
• Metabolism: Hepatic oxidation (CYP3A4) → inactive metabolites.
• Elimination: Renal excretion of metabolites; half‑life 1.5–2 h (oral), 2–5 h (IV).
• Special Populations: Dose adjustments not routinely required, but consider hepatic impairment or concurrent CYP3A4 inhibitors.

Indications

• Inflammatory arthritis (e.g., rheumatoid arthritis flare)
• Neuro‑muscular disorders (e.g., myasthenia gravis, Guillain‑Barré)
• Asthma & COPD exacerbations
• Severe allergic reactions (e.g., anaphylaxis prophylaxis)
• Autoimmune nephritis and vasculitis
• Ocular inflammation (e.g., uveitis)

Contraindications

• Active, uncontrolled infections (particularly fungal, TB, and viral)
• Known hypersensitivity to methylprednisolone
• Addison’s disease (uncontrolled adrenal insufficiency)
• Peptic ulcer disease with active ulceration
• Uncontrolled diabetes mellitus or hypertension (especially with long‑term use)
• Warn: Use caution in pregnancy (Category C), breastfeeding, and during active psychosis.

Dosing

• Taper: Initiate gradual taper within 7–10 days to avoid adrenal suppression.
• Intramuscular: 4 mg/kg IM once weekly for acute flares (rarely used now).

Adverse Effects

• Common: Insomnia, mood swings, mild hyperglycemia, increased appetite, mild GI upset.
• Serious:
• Adrenal insufficiency (if abruptly stopped)
• Osteoporosis with long‑term use
• Immunosuppression → opportunistic infections
• Severe hyperglycemia / Worsening of diabetes
• Hypertension, sodium retention

Monitoring

• Baseline & periodic:
• Fasting blood glucose & HbA1c
• Blood pressure & weight
• Serum electrolytes (Na⁺/K⁺)
• Bone density (DEXA) after >3 months continuous therapy
• During acute flare:
• CBC for leukocytosis or eosinophilia
• Liver enzymes if hepatic impairment suspected
• Patient‑report:
• Signs of infection, GI bleeding, mood or sleep changes

Clinical Pearls

• Tapering is key: The “sweet spot” for taper is typically 5 mg PO every 3–4 days; missing a dose can trigger adrenal crisis.
• Depot vs. Oral: Intramuscular Medrol (2 mg/mL) is ideal for patients who can’t take oral meds; it releases over 7–10 days, but watch for local injection pain.
• Preventive bone health: Even a 4‑week course can increase fracture risk in osteopenic patients—calcitriol, calcium, and bisphosphonates can be prophylactically initiated.
• Drug‑Drug Interactions: Caution with CYP3A4 inhibitors (ketoconazole) that may raise plasma levels, and with CYP3A4 inducers (rifampin) that may lower efficacy.
• Use in pregnancy: The risk–benefit window is narrow; if necessary, use the lowest effective dose and monitor fetal growth via ultrasound.
• Glucose control: Switch to insulin or adjust anti‑diabetic therapy around steroid courses to avoid hyperglycemic crises.

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• Key Terms Highlighted: *methylprednisolone acetate*, glucocorticoid, anti‑inflammatory, immunosuppressive, dosing taper, adrenal suppression, bone density, drug interaction.