Final answer:
Early signs of lithium toxicity involve nausea and vomiting, muscle weakness, fatigue, agitation, and anxiety. Such symptoms require immediate medical attention to prevent more severe effects.
Step-by-step explanation:
The early signs of lithium toxicity typically include symptoms such as nausea and vomiting, muscle weakness, and fatigue. Furthermore, lithium toxicity may cause agitation, anxiety, sleep problems, abnormal heart rhythms, low blood pressure, and muscular problems. These symptoms can progress to more severe conditions if the toxicity is not addressed, so it is crucial to seek medical attention if lithium toxicity is suspected.