Which drug should be avoided when given via arterial route or through an ET tube?

Dopamine hydrochloride should be avoided when administered via arterial route or through an endotracheal (ET) tube due to its potential to cause tissue necrosis and adverse local reactions if extravasation occurs. When given through these routes, there is a higher risk of unintended consequences because of the specific pharmacodynamics and the route of administration.

In the case of arterial delivery, dopamine can increase vasoconstriction and lead to tissue ischemia, especially if perfusion is insufficient. This complication is particularly problematic given that arterial administration is typically reserved for drugs with a well-established safety profile under such circumstances.

Similarly, when administered via an ET tube, dopamine's effectiveness can be markedly reduced. The ET route does not allow for optimal absorption and distribution compared to intravenous administration, which can lead to inadequate therapeutic effects. Thus, dopamine is not suitable for these routes of delivery, making its avoidance critical in such scenarios. Other agents listed may have specific uses and risks, but they do not carry the same level of critical caution as dopamine when considering arterial or ET tube delivery.