Lithium: The Dispensing Safety Checklist

📋 First Dispense Essentials

Mandatory items to issue

• Ensure the patient has all three NHS lithium resources: the alert card, the information booklet, and the monitoring booklet. These must be provided at the point of prescribing and are available to order from NHS England. Replacements can be sourced via the SPS guidance on accessing high-risk medicine resources.
• Confirm the prescription is written by brand name and formulation. Record the brand, formulation, and dose in the pharmacy medication record.
• Check that a baseline lithium level has been taken and is within the agreed individual target range. Confirm that renal function (estimated glomerular filtration rate), thyroid function, and calcium have been measured before starting treatment.

Baseline clinical checks

• Lithium level: therapeutic target ranges are individual and must be agreed with the prescriber and documented. Routine monitoring target is 0.4 to 1.0 mmol/L for long-term use (up to 1.0 mmol/L for acute mania), but some patients have a lower individual target. The therapeutic range should be recorded in the patient's monitoring booklet or pharmacy medication record.
• Renal function: lithium is entirely renally excreted. Even mild renal impairment reduces clearance and increases the risk of accumulation and toxicity. Dose adjustment is required in renal impairment.
• Thyroid function: long-term lithium causes hypothyroidism in up to 40% of patients. Symptoms can be subtle and may be attributed to the underlying psychiatric condition if not monitored.
• Calcium and parathyroid function: lithium can impair parathyroid function over time, leading to hypercalcaemia. Calcium should be checked every 6 months.
• Weight: checked at least annually. Unexplained weight loss may indicate worsening depression; weight gain may indicate developing hypothyroidism.

Key risks and lifestyle traps

• Lithium brands are not bioequivalent and are not interchangeable. Tablet brands (lithium carbonate) include Priadel, Camcolit, and Liskonum. Liquid brands (lithium citrate) include Priadel liquid and Li-Liquid. Switching between brands or formulations requires prescriber review and close monitoring of lithium levels.
• Key drug interactions that increase lithium levels and risk of toxicity: ACE inhibitors (angiotensin-converting enzyme inhibitors), angiotensin receptor blockers, thiazide diuretics, and non-steroidal anti-inflammatory drugs (NSAIDs). Check the patient record for any of these at every dispense.
• Sodium-containing over-the-counter products (effervescent tablets, antacids, health salts) can alter lithium levels. Advise patients to avoid ibuprofen and sodium-containing products without first checking with the pharmacy.
• Dehydration raises lithium levels rapidly. Causes include vomiting, diarrhoea, fever, excess heat, and some medicines including diuretics. Patients should be counselled to maintain consistent fluid and salt intake and to contact their prescriber if they become unwell.
• Neurotoxicity can occur even when plasma lithium levels are within the target range, particularly in frail or older patients. The absence of a raised level does not rule out toxicity.

First dispense script

🔄 Repeat Dispense Screen

Mandatory documentation

• Record the brand name, formulation, and dose dispensed on every occasion. If a different brand is supplied for any reason, document this and the prescriber agreement obtained.
• Record the date of the most recent lithium level and whether monitoring is current. Flag any overdue monitoring and document any action taken.

Ongoing clinical checks

• Lithium level is usually monitored every 3 months. If it appears more than 4 months overdue, contact the prescriber or mental health team to confirm monitoring arrangements before dispensing.
• Renal function, thyroid function, and calcium are usually monitored every 6 months, though some patients require more frequent testing. If overdue, advise the patient to book a blood test and inform the prescriber.
• Check for new interacting medicines, particularly ACE inhibitors (angiotensin-converting enzyme inhibitors), angiotensin receptor blockers, NSAIDs (non-steroidal anti-inflammatory drugs), and diuretics.
• Confirm the brand and formulation match the previous supply. Do not switch without prescriber agreement.

Ask the patient at the counter

• "Have you had your lithium blood tests recently?"
• "Have you started any new medicines, including anything bought without a prescription?"
• "Have you had any sickness, diarrhoea, dehydration, or changes in fluid intake recently?"

Lifestyle and surgical alerts

• Take lithium at the same time each day (usually in the evening to allow 12 hours between the last dose and the blood test). Missed doses should not be doubled up.
• Maintain consistent fluid intake and salt intake. Dehydration and low-salt diets both increase lithium levels. Advise extra caution during hot weather, illness, or exercise.
• Avoid ibuprofen and other non-steroidal anti-inflammatory drugs (NSAIDs) unless specifically agreed with the prescriber. These raise lithium levels.
• Women of childbearing potential should use effective contraception and discuss the risks with their specialist. Lithium is associated with cardiac malformations in the fetus, particularly Ebstein anomaly, though the absolute risk is low.
• Driving and operating machinery: lithium may cause drowsiness, impaired coordination, or visual disturbance, particularly during dose changes or when levels are high.

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