C. Ipratropium and tiotropium

Inhaled ipratropium and inhaled tiotropium are quaternary derivatives of atropine. These agents are approved as bronchodilators for maintenance treatment of bronchospasm associated with chronic obstructive pulmonary disease (COPD),both chronic bronchitis and emphysema. These agents are also pending approval for treating asthma in patients who are unable to take adrenergic agonists. Because of their positive charges, these drugs do not enter the systemic circulation or the CNS, isolating their effects to the pulmonary system. Tiotropium is administered once daily, a major advantage over ipratropium, which requires dosing up to four times daily. Both are delivered via inhalation.