Bipolar Pharmacology Flashcards
Lithium
Lithium is the drug of choice for acute mania. It is a mood stabilizer. There are two main pathways that Lithium affects: membrane pathway and cyclic pathway. Lithium will block the inositol/Na+ pump, preventing inositol being pumped into the post synaptic nerve. It will also block IP2 converting to IP1, and IP1 converting back to inositol. This blocks PKC and Ca++ signalling, therefore inhibiting NT release and gene expression.
Valproic Acid/Valproate
Anticonvulsant.
It is a Na+ channel blocker, inhibition of GABA transaminase and t-type Ca++ channel blocking. Additionally blocks glucose involvement in the IP cycle. Valproate is a mood stabiliser, initially developed for epilepsy. It has been shown to relieve symptoms of mania and mood swings. Used when lithium cannot be tolerated. Has shown benefits in those who experience rapid cycling.
What does GABA transaminase do?
Blocks the degradation of GABA, resulting in higher levels of GABA in the synapse (increased suppression of the nerve).
Lamotrigine
Anticonvulsant (newer anti-epileptic).
Na+ channel blocking, inhibition of glutamate release. Relieves symptoms of mania and reduces mood swings.
Considered for depressive episodes or maintenance treatment.
Carbamazepine
Anticonvulsant.
Voltage-gated Na+ channel block. Relieves symptoms of mania and reduces mood swings.
Olanzapine
Atypical Antipsychotic.
Blocks D2 receptors in the part of the brain that controls psychosis. Weak blockage or competes with serotonin.
Combined with lithium or valproic acid.
Can antidepressants be administered for bipolar disorder?
The use of ADs are debated. Some report worse outcomes with their use triggering manic, hypomanic or mixed episodes. Rapid cycling can also be induced or made worse with ADs.
Benzodiazepines
BZDs can only be given in the first few weeks before clinical relief is experienced from mood stabilizers. Relieves symptoms of anxiety, agitation or insomnia.
Calcium Channel Blockers
Have a mood stabilizing effect. Can be given in those who can’t tolerate lithium or anticonvulsants.
Thyroid Medication
Bipolar patients can often have abnormally high levels of thyroid hormone. Particularly prevalent rapid cyclers. Lithium can also cause low thyroid hormone. In these cases thyroid medication is added to drug treatment regime.
What is bipolar disorder?
It is a treatable medical illness marked by extreme changes in mood, thought, energy, and behaviour. A person’s mood can alternate between ‘poles’ (manic and depression). Mood changes can last for hours, days, weeks or even months.
Cause is unknown.
When is an intervention for Bipolar Disorder given?
When mood swings are severe and impacting everyday life of the patient and their family.
What are the symptoms of mania?
- increased physical and mental activity
- heightened mood and self-confidence
- racing speech
- decreased need for sleep
- delusions and hallucinations
What are the symptoms of depressive phase?
- prolonged sadness
- social withdrawal
- guilt, worthlessness
- irritability and anger
- recurring thoughts of death or suicide
What is the rationale for pharmacological treatment of Bipolar Disorder?
- treat symptoms of mania
- treat depression
- prevent recurrence of manic or depressive symptoms
- prevent complications such as suicide
