Beta-adrenergic agonists can be broadly categorized as having beta1 and beta2 receptor activity. This section describes the toxicity of beta2-selective agonists that are commonly available for oral use: albuterol (salbutamol), metaproterenol, and terbutaline (Table II–16). Clenbuterol, a potent beta2 agonist, is not approved for human use in the United States but is abused for its anabolic effects.