Clinical pharmacy最新文献

The immunology, pathophysiology, incidence, clinical manifestations, grading, and prevention of acute graft-versus-host disease (GVHD) are reviewed. GVHD occurs after allogeneic marrow transplantation when immunologically competent T lymphocytes in the donor marrow identify the host's antigens as foreign and attempt to reject host tissues. Acute GVHD occurs within three months after marrow transplantation and may affect the skin, gastrointestinal tract, liver, and immune system. Even with prophylactic immunosuppression, acute GVHD occurs in 20% to 80% of patients. Moderate to severe GVHD (grades II-IV) is a major cause of morbidity and mortality after allogeneic bone marrow transplantation. Conventional GVHD prophylaxis consists of immunosuppressives such as corticosteroids, methotrexate, and cyclosporine. Methotrexate and cyclosporine are equally effective in preventing GVHD. A combination of both drugs is better than either drug alone and results in an improved survival rate. The addition of corticosteroids to methotrexate, cyclosporine, or antithymocyte globulin is also more effective than single-drug therapy. Serial administration of intravenous immune globulin may contribute additional protection against acute GVHD. There is conflicting evidence concerning the prophylactic efficacy of pentoxifylline. Elimination of T lymphocytes from the donor marrow before transplantation has been associated with less GVHD but a higher incidence of graft failure. Total elimination of GVHD in patients with leukemia may cause loss of a graft-versus-leukemia effect, resulting in increased relapse rates and decreased long-term survival. Promising experimental prophylactic agents include thalidomide, zolimomab aritox, tacrolimus, antibodies to cytokines involved in the pathogenesis of GVHD, and monoclonal antibodies against cytokine receptors on T lymphocytes. Current research efforts are also directed toward eliminating GVHD without compromising the graft-versus-leukemia effect.

The epidemiology, pathophysiology, diagnosis, evaluation, and treatment of atrial fibrillation (AF) and atrial flutter (AFl) are reviewed, and recent developments and controversies in the approach to these arrhythmias are addressed. AF and AFl are the arrhythmias most frequently encountered in clinical practice. Although occasionally unaware of their arrhythmia, patients usually complain of palpitations, weakness, dyspnea, and decreased exercise tolerance. The initial goal of therapy is control of the ventricular rate. Rate control is accomplished with atrioventricular node-blocking agents such as digoxin, calcium-channel blockers, or beta-adrenergic blockers. Along with a rapid, irregular ventricular response, other detrimental outcomes of AF and AFl include compromised hemodynamics and increased vulnerability to thromboembolism. After the cause of the patient's arrhythmia has been evaluated, pharmacologic treatment is directed at converting the rhythm to normal sinus rhythm and maintaining it. Antiarrhythmic drugs have proved effective in about 50% of cases but may be associated with increased mortality. More effective and safer forms of drug therapy for AF and AFl are needed. Nonpharmacologic alternatives to antiarrhythmic medications for refractory AF and AFl include radio-frequency catheter ablation of the bundle of His with pacemaker placement and surgery. Patients who remain in AF despite therapy should receive long-term warfarin treatment. Drugs may be used to control the ventricular response in patients with AF and AFl, terminate and prevent the arrhythmias, and prevent thromboembolism. Nonpharmacologic treatments are reserved for patients whose arrhythmias are poorly controlled by drugs.

The role and adverse effects of methotrexate in the treatment of chronic corticosteroid-dependent asthma are discussed. Methotrexate is a folic acid antagonist that has been used as an anti-inflammatory agent in the treatment of arthritis. It also appears to be effective in reducing the corticosteroid requirements in patients with chronic corticosteroid-dependent asthma, a use that was first reported in 1986. Studies of this use of methotrexate in adults support a trial of methotrexate in patients with severe asthma who have been unable to discontinue corticosteroid use despite aggressive management of their asthma and who are experiencing severe corticosteroid toxicity. Experience with methotrexate in children with asthma is limited to case series. Adverse effects associated with the use of methotrexate for treatment of corticosteroid-dependent asthma include nausea, elevated serum aminotransferase, diarrhea, and thinning of hair. While methotrexate appears to reduce corticosteroid requirements in patients with chronic corticosteroid-dependent asthma, its role in asthma therapy still needs to be clarified.

Cases of hypothyroidism and hyperthyroidism associated with amiodarone therapy are described, and the mechanisms, clinical appearance, and management of amiodarone-induced thyroid dysfunction are discussed. A 72-year-old man with a history of recurrent ventricular tachycardia unresponsive to conventional antiarrhythmic drugs was started on amiodarone therapy. Initially he responded well, but after three months he began to have fatigue, dry skin, and intolerance of cold. His serum thyroid-stimulating hormone (TSH) concentration had risen from 4.4 microU/mL before amiodarone therapy began to 20 microU/mL, consistent with hypothyroidism. He was started on sodium levothyroxine for thyroid hormone replacement; the dosage was adjusted in accordance with subsequent TSH measurements. His hospital course was complicated by congestive heart failure. The second patient was a 43-year-old man with a history of atrial fibrillation who developed hyperthyroidism when placed on amiodarone therapy. He had persistent sweating, intolerance of heat, restlessness, and tachycardia. Thyroid function tests confirmed the presence of hyperthyroidism. The patient was treated with propylthiouracil and propranolol, and amiodarone was discontinued. He remained unresponsive to the propylthiouracil, which was discontinued, and was scheduled for radioactive iodine treatment. The mechanism of amiodarone-induced thyroid dysfunction may involve the large iodine content of the drug. Amiodarone-induced hypothyroidism may range in severity from mild symptoms to severe myxedema; the skin, hair, and nails are particularly affected. Persons with clinical hyperthyroidism secondary to amiodarone treatment show the signs and symptoms of a hypermetabolic state resulting from thyroid hormone excess. Amiodarone-induced hypothyroidism is treated with levothyroxine and hyperthyroidism with antithyroid drugs. Amiodarone can cause thyroid dysfunction, which can have serious consequences.