A client taking lithium carbonate for bipolar disorder calls the nurse reporting nausea, diarrhoea, and a coarse hand tremor. Their last lithium level was 1.4 mEq/L (therapeutic 0.6-1.2). What should the nurse advise?

LITHIUM TOXICITY is a medical emergency requiring immediate intervention. The combination of supratherapeutic lithium level (1.4 mEq/L above the therapeutic range of 0.6-1.2) with SYMPTOMS of toxicity represents an urgent situation. LITHIUM TOXICITY PROGRESSION: EARLY (1.5-2.0 mEq/L): Fine-to-coarse hand tremor (progressing from the expected fine tremor at therapeutic levels); Nausea, vomiting, diarrhoea; Muscle weakness; MODERATE (2.0-2.5 mEq/L): Drowsiness, confusion, ataxia (unsteady gait); Slurred speech; Muscle twitching; Blurred vision; SEVERE (above 2.5 mEq/L): Seizures; Cardiac arrhythmias; Stupor/coma; Irreversible neurological damage; Death. WHY 1.4 IS CONCERNING: While 1.4 is only slightly above the therapeutic maximum, the SYMPTOMS indicate the patient's body is reacting adversely — symptoms at any level warrant evaluation; individual sensitivity varies; IMMEDIATE MANAGEMENT: HOLD lithium; emergency evaluation including repeat serum lithium level; fluid replacement (normal saline — dilutes lithium and promotes renal excretion); for severe toxicity: haemodialysis effectively removes lithium; PRECIPITATING FACTORS: Dehydration (vomiting, diarrhoea, excessive sweating, insufficient fluid intake); sodium restriction; NSAIDs (increase renal lithium retention); ACE inhibitors; thiazide diuretics. PATIENT EDUCATION: Maintain consistent fluid/sodium intake; report early symptoms; know when to seek emergency care; carry a medical alert identifier.