Begin with 500 mg BID, and if the drug is tolerated, increase the dose to 1 g bid after 4 weeks. If diarrhea occurs, try 1 to g/day. Other side effects include gastrointestinal hemorrhage and perforation; increased susceptibility to infections is a consideration with all of these agents, particularly in combination with corticosteroids. Neutropenia is generally associated with doses of 2 g/day or greater. Mycophenolate mofetil eventually may replace azathioprine as the first-line immunosuppressive drug in patients with MG, but further studies are required.
Reports of acute toxicity and metabolic disturbances with glucocorticoids are rare but do occur. There is no clinical syndrome of acute overdosage with Methylprednisolone . Acute overdose may possibly aggravate pre-existing disease states such as ulceration of the gastrointestinal tract, electrolyte disturbances, infections, diabetes and oedema. Repeated high doses of methylprednisolone have caused hepatic necrosis and an increase in amylase. Bradyarrhythmias, ventricular arrhythmias and cardiac arrest have been observed in cases of intravenous administration of high doses of methylprednisolone.
Corticosteroids may cause hypernatremia, hypokalemia, fluid retention, and elevation in blood pressure. These mineralocorticoid effects are most significant with fludrocortisone, followed by hydrocortisone and cortisone, then by prednisone and prednisolone. The remaining corticosteroids, betamethasone, dexamethasone, methylprednisolone, and triamcinolone, have little mineralocorticoid activities. However, large doses of any corticosteroid can demonstrate these effects, particularly if given for longer than brief periods. Therapy with corticosteroids should be administered cautiously in patients with preexisting fluid retention, hypertension, congestive heart failure, and/or renal dysfunction. Dietary sodium restriction and potassium supplementation may be advisable.