Pharmacology - Mood stabilisers and anticonvulsants

Question 1

What are mood stabilisers?

Answer 1

Drugs used to treat bipolar disorder type I or type II, borderline personality disorder (BPD) and schizoaffective disorder.

Question 2

What are some examples of mood stabilisers?

Answer 2

1. Mineral
   Lithium
2. Anticonvulsants
   Valporate
   Lamotrigine
   Carbamazapine
3. Antipsychotics
   Risperidone
   Olanzapine

Question 3

What is the theraputic range for lithium?

Answer 3

0.4-1.0 mmol/L

Question 4

What lithium monitoring should be done?

Answer 4

When checking lithium levels
The sample should be taken 12 hours post-dose

After starting lithium
levels should be performed weekly and after each dose change until concentrations are stable

Once established
Lithium blood level should ‘normally’ be checked every 3 months

Change in dose
Week later and weekly until stable

Thyroid and renal function should be checked every 6 months

Question 5

What are the different types of lithium toxicity?

Answer 5

Acute

Chronic

Acute on chronic

Question 6

What can cause lithium toxicity?

Answer 6

1. Dehydration
2. Renal failure
3. Drugs: diuretics (especially thiazides), ACE inhibitors/angiotensin II receptor blockers, NSAIDs and metronidazole.

Question 7

Where is lithium mainly excreted?

Answer 7

By the kidneys

Question 8

What drugs can interact with lithium?

Answer 8

Lithium levels raised with a patient on a drug which reduces excretion of lithium.

1. Antipsychotics
2. ACE inhibitors
3. NSAIDs

Question 9

What are the adverse affects of lithium?

Answer 9

1. Hyperparathyroidism and resultant hypercalcaemia
2. Thyroid: enlargement, may lead to hypothyroidism
3. Nausea/vomiting, diarrhoea
4. Fine tremor
5. Nephrotoxicity: polyuria, secondary to nephrogenic diabetes insipidus
6. ECG: T wave flattening/inversion
7. Weight gain
8. Idiopathic intracranial hypertension
9. Leucocytosis

Question 10

What are the levels of lithium that cause toxicity?

Answer 10

Lithium toxicity generally occurs following concentrations > 1.5 mmol/L.

Question 11

What are the symptoms of acute lithium toxicity?

Answer 11

1. Coarse tremor (a fine tremor is seen in therapeutic levels)
2. Acute confusion
3. Blackout/Coma
4. Increased urine output
5. Seizure
6. Hyperreflexia

Question 12

What are the symptoms of chronic lithium toxicity?

Answer 12

1. Nystagmus
2. Tremor
3. Hyperreflexia
4. Ataxia
5. Change in mental status

Question 13

What are the symptoms of acute on chronic lithium toxicity?

Answer 13

Symptoms of both

Question 14

How do you diagnose lithium toxicity?

Answer 14

1. Fingerstick glucose
2. Serum lithium concentration
3. Basic metabolic panel to assess renal function
4. Serum acetaminophen and salicylate concentrations to rule out other sources of acute ingestion
5. Urine pregnancy tests to ensure management does not cause abortion

Question 15

Whats the treatment for lithium toxicity?

Answer 15

1. Stop lithium
2. Gastric lavage - Medicines that increase lithium excretion by the kidneys

Mild-moderate toxicity
Volume resuscitation with normal saline

Severe toxicity
haemodialysis

Sodium bicarbonate is sometimes used but there is limited evidence to support this. By increasing the alkalinity of the urine it promotes lithium excretion