The effects of cortisone,
dexamethasone, fludrocortisone,
hydrocortisone, methyl-
prednisolone,
prednisolone and
prednisone can be markedly reduced by
rifampicin.
The significance of the falls in corticosteroid levels will depend on the disease the corticosteroid is prescribed for. Monitor the outcome of concurrent use closely, especially in transplant patients, and increase the dose accordingly. Topical preparations are not likely to be affected.
C Corticosteroids+Salbutamol(Albuterol)andrelated
bronchodilators
Beta2 agonists, such as salbutamol, can cause hypokalaemia. This can be increased by other potassium-depleting drugs such as the
corticosteroids. In severe cases the risk of serious cardiac arrhythmias could be increased.
The CSM in the UK advises monitoring potassium in severe asthma, because of the probability of multiple potassium-depleting drugs being used, and because some conditions predispose these patients to hypokalaemia (e.g.
hypoxia). Consider monitoring based on the severity of the patient's condition, and the number of potassium-depleting drugs used.