Treatment: lithium

Fasting laboratory tests

• FBC
• Serum electrolytes
• Serum creatinine with eGFR
• Serum calcium
• AST
• ALT
• GGT
• Alkaline phosphatase
• Serum bilirubin
• Fasting plasma glucose
• Lipid profile
• TSH
• β-hCGif neededWoman of childbearing potential: make sure she is not pregnant and start effective contraception before treatment ^[2].
• PTH (if serum calcium raised)if needednon-French guidelineThe Netherlands measures serum calcium and PTH before lithium, then twice a year (nephrologists, 2013, taken up by the 2026 guideline) ^[3,4]; CANMAT/ISBD and a 2026 review recommend looking for hyperparathyroidism if serum calcium rises ^[5,6]. The French SmPC and ALD 23 do not provide for this test ^[2,7]. Hyperparathyroidism: see the page “Hypercalcaemia”.

Urine tests

• Urine albumin:creatinine ratio or protein:creatinine ratio in non-diabetic patients
• Urine albumin:creatinine ratio in diabetic patients

Laboratory tests to be done in the morning, 12 h after the last lithium dose

• Serum lithium

to be done every week in the first month, then every month until the end of the 3rd month, i.e.

• in 1 week
• in 2 weeks
• in 3 weeks
• in 4 weeks
• in 8 weeks
• in 12 weeks

At the 3-month (12-week) tests, add

• TSH

Laboratory tests to be done in the morning, 12 h after the last lithium dose

• Serum lithium
• Serum electrolytes
• Serum creatinine with eGFR
• TSH
• serum calciumLong-term monitoring: lithium can cause hypercalcaemia through hyperparathyroidism.
• PTH (if serum calcium raised)if needednon-French guidelineThe Netherlands measures serum calcium and PTH before lithium, then twice a year (nephrologists, 2013, taken up by the 2026 guideline) ^[3,4]; CANMAT/ISBD and a 2026 review recommend looking for hyperparathyroidism if serum calcium rises ^[5,6]. The French SmPC and ALD 23 do not provide for this test ^[2,7]. Hyperparathyroidism: see the page “Hypercalcaemia”.
• urine protein:creatinine ratio on a spot urine sampleif neededLong-term renal follow-up: proteinuria is sought before treatment ^[2] and the urine protein or albumin:creatinine ratio is part of the follow-up listed in ALD 23 ^[7].

Laboratory tests to be done in the morning, 12 h after the last lithium dose

• Serum lithium
• twice a week, until a concentration between 0.5 and 0.8 mEq/L is reached

Laboratory tests to be done in the morning, 12 h after the last lithium dose

• Serum lithium
• on D7, D14 and, if necessary, D21, until a concentration between 0.8 and 1.2 mEq/L is reached

Laboratory tests 5 to 7 days after the change (without delay if signs of overdose)

• Serum lithium
• Serum electrolytes
• Serum creatinine with eGFR

Every 3 to 6 months (serum lithium in the morning, 12 h after the last dose)

• Serum lithium
• Serum creatinine with eGFR
• Urea

Every 6 to 12 months, fasting

• TSH
• Serum calcium
• Fasting plasma glucose
• Lipid profile

Every year

• FBC