Tremor and β(2)-adrenergic agents: is it a real clinical problem?
Tremor is one of the most characteristic adverse effects following administration of β(2)-adrenergic agonists. It is reported by around 2-4% of patients with asthma taking a regular β(2)-adrenergic agonist and is induced by both short-acting and long-acting agents. Tremor associated with β(2)-adrenergic agonists is dose-related and may occur more commonly with oral dosing. The exact mechanism for tremor induction by β(2)-adrenergic agonists is still unknown, but there is some evidence that β(2)-adrenergic agonists act directly on muscle. An early explanation of the tremor was that β(2)-adrenoceptor stimulation shortens the active state of skeletal muscle, which leads to incomplete fusion and reduced tension of tetanic contractions. More recently, tremor has been correlated closely with hypokalaemia. A possible diverse impact of different modes of administration of β(2)-adrenergic agonists on tremorogenic responses has been suggested but solid evidence is still lacking. In any case, the desensitization of β(2)-adrenoceptors that occurs during the first few days of regular use of a β(2)-adrenergic agonist accounts for the commonly observed resolution of tremor after the first few doses. Therefore, tremor is not a really important adverse effect in patients under regular treatment with a β(2)-adrenergic agonist.
Unit of Respiratory Clinical Pharmacology, Department of Internal Medicine, University of Rome Tor Vergata, Rome, Italy. mario.cazzola@uniroma2.it
Mario
M
Cazzola
Maria Gabriella
MG
Matera
D000284:Administration, Oral; D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D000336:Aerosols; D001993:Bronchodilator Agents / Q000009:adverse effects / Q000627:therapeutic use; D004361:Drug Tolerance; D006801:Humans; D014202:Tremor / Q000139:chemically induced* / Q000453:epidemiology / Q000503:physiopathology
D058666:Adrenergic beta-2 Receptor Agonists; D000336:Aerosols; D001993:Bronchodilator Agents