Epinephrine Heavy metal poisoning Methylphenidate Methysergide Monoamine oxidase inhibitors Oral contraceptives Phenylephrine Phencyclidine Phenylpropanolamine Pseudoephedrine Reserpine Endocrine Congenital adrenal hyperplasia Cushing syndrome Hyperaldosteronism Hyperparathyroidism Hyperthyroidism Pheochromocytoma Tumors Neuroblastoma Wilms tumor Miscellaneous Acute intermittent porphyria Hypercalcemia Hypernatremia Malignant hyperthermia Labetalol may be administered by intermittent bolus dosing, or by a bolus dose followed by a continuous infusion ( Table 37.5 ) Because of its β-blocking effects, it should not be used in patients with asthma, heart block, or CHF or for the treatment of hypertension in patients with pheochromocytoma or sympathomimetic drug overdose (e.g., cocaine; see Chapter 102 Toxicologic Emergencies ), due to the potential for unopposed alpha effects Nicardipine