What is typically the first sign associated with atropine toxicity?

The first sign associated with atropine toxicity is typically dry mouth. Atropine is an anticholinergic drug that blocks the action of acetylcholine at muscarinic receptors, leading to inhibition of salivary gland secretion. This causes a significant decrease in saliva production, resulting in xerostomia, or dry mouth, which can be one of the earliest and most noticeable effects of toxicity.

As atropine extends its effects on the body, other symptoms can develop, such as blurred vision due to pupil dilation and decreased accommodation, increased heart rate due to its peripheral effects on the autonomic nervous system, and even headache related to increased sympathetic tone or other physiological responses. However, dry mouth is usually the first and most characteristic sign after an overdose or toxicity. This understanding is crucial for recognizing atropine toxicity in a clinical setting.