Methotrexate is given weekly as an intramuscular injection of 15 to 25 mg. Side effects are rare and include leukopenia and hypersensitivity interstitial pneumonitis. Hepatic fibrosis is the most severe potential sequela of long-term therapy. Patients with concomitant alcohol abuse and/or morbid obesity are more likely to develop hepatic fibrosis and therefore should not be treated with methotrexate. It is prudent to obtain a baseline chest radiograph and to monitor complete blood count, liver function and renal function every two weeks until the patient is receiving oral therapy, and every one to three months thereafter. Before methotrexate therapy is initiated, the risks of treatment and the possible need for a liver biopsy should be discussed with the patient.
It should be borne in mind that prolonged corticosteroid therapy frequently causes an impairment in the activity of the hypothalamic-pituitary-adrenal axis and a reduction in the size of the adrenal cortex. A potentially critical degree of impairment or insufficiency may persist asymptomatically for some time even after gradual discontinuation of adrenocortical steroids. Therefore, if a patient is subjected to significant stress, such as a severe asthmatic attack, surgery, trauma or severe illness while being treated or within one year (occasionally up to two years) after corticosteroid treatment has been terminated, consideration should be given to reinstituting corticosteroid therapy. When respiratory function is impaired, as may occur in severe exacerbation of asthma, a temporary increase in the amount of corticosteroids may be required to regain control of the patient's asthma.