Why is ipratropium considered to be better tolerated than atropine?

Ipratropium is considered to be better tolerated than atropine primarily because it has minimal systemic absorption and poor central nervous system (CNS) penetration. This characteristic of ipratropium significantly reduces the risk of systemic side effects commonly associated with atropine.

Atropine is a systemic anticholinergic that can cause a range of side effects due to its ability to enter the CNS, potentially leading to sedation, confusion, and anticholinergic effects such as dry mouth and increased heart rate. In contrast, ipratropium, being delivered via inhalation, predominantly acts locally in the lungs with very limited systemic effect. This localized action allows for effective bronchodilation in conditions such as asthma or COPD without the significant side effects that might accompany systemic absorption, making ipratropium a more favorable option for patients requiring bronchodilation.

The other choices, while they present various comparisons, do not encompass the primary reason linked to the improved tolerability of ipratropium over atropine as effectively as the aspect of systemic absorption and CNS penetration.