Mental Health Update - Lithium

Question 1

What are the main features of Lithium? (4)

Answer 1

Brand only Rx (started on secondary/shared care not primary without specialist advice)
6 month trial
Therapeutic effects (acute mania, prophylactic agent for mania/depression, antidepressant)
1st line for LT management tx to prevent relapse.

Question 2

What are the monitoring requirements for Lithium? (10)

Answer 2

Every 6 month during tx (more frequently in early stages of tx)
- Serum electrolytes
- eGFR
- Body-weight/BMI/waist circumference/lipids
- Thyroid function
- Calcium levels
- FBC (on initiation) + ECG if cardiac risk factors)

Lithium levels at least every 3-6 months:
- Initially weekly
- Additional tests e.g. signs of toxicity
- Additional test 5-7 days after every dose change or starting/stopping interacting drugs.

Question 3

What are the lithium levels? (3)

Answer 3

0.6-0.8mmo/L
0.8-1.0mmol/L
Toxicity = > 1.5mmol/L

Question 4

When should lithium levels be taken? (1)

Answer 4

12 hours post dose (10-14 hrs okay in practice)

Question 5

What are the common s/e of Lithium? (8)

Answer 5

Fine tremor
Sedation
Impaired co-ordination
GI disturbances
Polyuria
Polydipsia
QT prolongation

Question 6

What are the longer term s/e of Lithium? (4)

Answer 6

Weight changes
Thyroid disorders
Hyperparathyroidism
Renal impairment

Question 7

What are the signs of Lithium toxicity? (9)

Answer 7

Appetite loss
Diarrhoea/Vomiting
Blurred vision
Marked tremor
Unsteadiness
Slurred speech
Drowsiness/Confusion

> 2mmol/L:
- Muscle twitches
- Severe drowsiness/confusion
- Convulsions
- Unconsciousness

Question 8

What are the common interactions of Lithium? (6)

Answer 8

Any drug impacting renal function or sodium levels.
Diuretics, NSAIDs, ACEI = monitor renal function if co-Rx (assess +/- before Rx often alternative is considered)
Antidepressant (5-HT syndrome)
Carbamazepine
Haloperidol

Question 9

Explain Lithium’s bioavailability. (3)

Answer 9

Narrow therapeutic index
Liquid and tablets are not interchangeable.

Question 10

What px advice is given when taking Lithium? (11)

Answer 10

Lithium tx pack: info booklet, alert card, record book for tracking serum-lithium concentration.
Take lithium every day. Try not to miss any doses.
Carry lithium card at all times.
Advise px that each time they collect Rx check the brand is the same as usual.
Tell pharmacist before buying OTC products or supermarket medications.
Maintain adequate fluid intake to avoid dehydrations.
Avoid dietary changes tat reduce or increase sodium intake.
Will need to have regular blood tests - dose may be adjusted depending on blood test results.
Check before taking other medicines e.g. NSAIDs.
Women of childbearing age advised to use reliable contraception.
Managing missed doses.
Common s/e (dry mouth, metallic taste in mouth, feeling thirsty, weight gain, fluid retention. Try to drink low calorie drinks to avoid weight gain.)