Which type of medication should be used with caution in patients with cardiac disease?

Beta-agonists are medications that stimulate beta-adrenergic receptors, which are found not only in the lungs but also in the heart. These medications can cause an increase in heart rate and blood pressure due to their stimulatory effects. In patients with existing cardiac disease, such as arrhythmias, hypertension, or coronary artery disease, the use of beta-agonists can exacerbate these conditions, leading to potential complications.

In contrast, antihistamines are primarily used to relieve allergy symptoms and may have some sedative effects, but they are generally not as impactful on cardiac function as beta-agonists. Corticosteroids are anti-inflammatory agents that can be used safely in many patients with respiratory issues, although their long-term use may have other systemic effects. Mucolytics are intended to thin mucus and aid in expectoration and typically do not significantly affect cardiac function.

Therefore, beta-agonists require caution in patients with cardiac disease due to their potential to increase heart rate and blood pressure, making them the correct answer in this context.