HIGH RISK DRUGS

Question 1

Does lithium need to be maintained by brand?

Answer 1

YES

Question 2

What is the therapeutic range for lithium for:

• prophylaxis and the elderly
• acute episode of mania/previous relapse/subsyndromal symptoms

Answer 2

prophylaxis and elderly = 0.4 - 1 mmol/L

Acute episodes = 0.8 - 1 mmol/L

Question 3

When is lithium sampled

Answer 3

12 hours post dose

Question 4

How often is lithium plasma levels monitored?

Answer 4

Weekly monitoring on initiation and after dose changes
Then every 3 months when stable
Then every 6 months once stable for a year

(need additional monitoring for intercurrent illness or significant change to diet or water intake)

Question 5

How should lithium be withdrawn?

Answer 5

Not abruptly due to risk of relapse

needs at least 4 weeks, ideally over 3 months

Question 6

What are common side effects of lithium

Answer 6

• weight gain
• thyroid disorders
• renal impairment
• Qt prolongation
• benign intracranial hypertension

Question 7

What are the monitoring parameters when initiating lithium?

Answer 7

Renal 
Cardiac, ECG if CVD/risk factors
Thyroid 
BMI
Serum electrolytes
FBC

Question 8

What parameters should be monitored in lithium every 6 months?

Answer 8

BMI/weight
serum electrolyttes
eGFR
thyroid

Question 9

What are the symptoms of lithium toxicity

Answer 9

Renal disturbances- polyuria, incontinence, hypernatraemia - excess urination and thirst
Extrapyramidal symptoms - temor, myoclonus, nystagmus
Visual - blurred vision
Nervous system - confusion, drowsy, in-coordination
GI - diarrhoea, vomiting

Question 10

What factors predispose to lithium toxicity

Answer 10

Hyponatraemia, high salt intake causing higher thirst, changes in diet/water intake, intercurrent illness e.g. diarrhoea/vomiting
Dehydration

Question 11

Provide counselling points for lithium

Answer 11

Report signs and symptoms of toxicity -drowsy, tremor, myoclonus/nystagmus, dizziness , blurred vision

Report persistent headaches/visual distubances

Report any symptoms of hypothyroidism e.g. weight gain, fatigue

Report polyuria or polydipsia (excess urine or thirst)

Maintain a constant water and salt intake and avoid dehydration (caution in infection/illness, avoiding dietary changes)

May make drowsy - caution in driving and avoid alcohol

Avoid OTC products such as ibuprofen, soluble analgesics, antacids

Keep lithium treatment pack - and carry alert card

Question 12

What is included in a lithium treatment pack

Answer 12

PIL
Alert cad
Record book

Question 13

Can lithium be used in pregnancy or BF?

Answer 13

NO
- teratogenic esp in 1st trimester - cardiac abnormalities - need contraception

toxicity in breast-fed infants

Question 14

What OTC products cannot be used in patient taking lithium?

Answer 14

Soluble analgesics
NSAIDS
sodium containing antacids e.g. gaviscon

Question 15

What are key interactions of Lithium

Answer 15

• Drugs causing hyponatraemia e.g. diuretics, SSRIs
• Drugs increasing seizure risk e.g. quinolones, ssri, epilepsy
• drugs prolonging QT and causing hypokalaemia (ABCDE)
• Nephrotoxic drugs e.g. ACE/ARB, NSAIDS
• drugs increasing risk of serotonin syndrome
• drugs increasing neurotoxicity e.g. anti-epileptics, antipsychotics,amitryptylline
• Risk of EPS with haloperidol, clozapine, phenothiazine antipsychotics, parkinsons, metoclopramide

Question 16

What is the interaction between ACE and Lithium?

Answer 16

Risk of nephrotoxicity

Question 17

If a patient comes in with an infection susceptible to quinolone antibiotics and Dr wants to start them on ciprofloxacin. The patients medications are: Lithium. Is this OK?

Answer 17

No - interaction between quinolones and lithium - increases seizure risk and also prolongs the QT interval

Question 18

What antidepressant should be avoided in a patient on lithium?

Answer 18

SSRIs due to risk of hyponatraemia (toxicity), serotonin syndrome, seizure risk, QT prolongation (if citalopram)