What is often the earliest sign of digitalis toxicity?

The earliest sign of digitalis toxicity is often nausea and vomiting, sometimes accompanied by a headache. This symptom can arise as the body's response to elevated levels of digitalis, which impacts the gastrointestinal system. Patients may experience a range of distressing gastrointestinal symptoms early on, as the drug affects both cardiac and non-cardiac systems. These early symptoms are crucial for monitoring, as they can indicate that toxicity is developing, allowing for timely intervention and management.

Other symptoms associated with digitalis toxicity, such as visual disturbances or arrhythmias, usually develop after the initial gastrointestinal symptoms are present. While fatigue and weakness are also common manifestations, they are more nonspecific and can be seen in many other conditions, which makes nausea and vomiting a clearer indicator of emerging toxicity in the context of digitalis use.