Bipolar Disorder - Pharmacology Flashcards
What are the 3 main groups of mood stabilisers?
Lithium, anti-convulsants and anti-psychotics
Which types of mood stabilisers are useful for both mood states?
Lithium and anti-psychotics
Which type of mood stabiliser is especially good for bipolar depression?
Lamotrigine
Which type of mood stabiliser is especially good for mania/hypomania?
Valproate
Should anti-depressants be given in bipolar disorder?
They should generally be avoided since they can trigger mania, but may be used short-term for a severe depressive episode
When giving an anti-depressant what other medication should the person always be on?
An anti-manic drug
When can depot IM anti-psychotic be given and why?
Given every 2-4 weeks if compliance is poor or if the patient is unwilling to take oral medication
What are the two main agents used for prophylaxis of bipolar?
Lithium and sodium valproate
What impact does lithium have on bipolar disorder?
Lowers the frequency and severity of relapses by half and significantly reduces the likelihood of suicide
When should lithium plasma levels be monitored before the therapeutic dose is reached?
Weekly, 12 hours after the last dose
What is the therapeutic plasma range of lithium?
Between 0.5 and 1.0mmol/l
When should screening take place for lithium use?
Prior to starting and at 6 month intervals thereafter
What are the 3 screening tests for lithium use?
TFTs, parathyroid function and renal function
Why are TFTs screened when using lithium?
Lithium can produce hypothyroidism
Why are parathyroid levels screened when using lithium?
Serum calcium and parathyroid hormone levels are increased in 10% of patients
Why is renal function screened for when using lithium?
Long term lithium treatment can cause nephrogenic diabetes insipidus and reduced glomerular function
Because of lithium toxicity, what should patients be warned when starting it?
Always carry a lithium card, be advised to avoid dehydration and drug interactions such as NSAIDs and diuretics
What are some causes of lithium toxicity?
Increased dose, dehydration drug interactions, reduced salt intake
What are the warning signs of lithium toxicity?
GI upset, blurred vision, coarse tremor, ataxia and drowsiness
What are some signs of severe lithium toxicity?
Confusion, loss of consciousness, seizures, coma, death
How is lithium toxicity treated?
Stopping lithium, IV fluids, monitoring of renal function, maybe dialysis
Should lithium be used in pregnancy?
It is not advised, particularly in the first trimester because of an increased risk of foetal malformation
It is likely that women with bipolar disorder will relapse after giving birth. How can this risk be reduced?
Restarting lithium within 24 hours of delivery (if prepared to forgo breastfeeding)
What is the mode of action of lithium?
The mode of action is unclear, but it is thought to act intracellularly as a secondary messenger system
When should lithium be used?
Gold standard for the prophylaxis of bipolar disorder and can also be given as an adjunct to anti-depressants in treatment resistant depression
What are some side effects of lithium?
GI upset, fine tremor, nephrotoxicity, hypothyroidism, weight gain
Why should lithium plasma levels be measured so often?
Because of a narrow therapeutic index
What blood test should be done every 5 days until on the therapeutic dose of lithium?
Us and Es
Once at a therapeutic level, how often should plasma lithium levels and Us and Es be measured in a patient on lithium?
Every 3 months
Once at a therapeutic level, how often should TFTs be measured in a patient on lithium?
Every 6 months
If a patient on lithium is dehydrated from physical illness, generally unwell or if there are signs of toxicity, what tests should be done?
Lithium plasma levels and Us and Es
When should lithium be taken and why?
At night due to sedation
What are the main drugs that lithium interacts with?
ACE inhibitors, NSAIDs, ARBs and diuretics
How should hypothyroidism as a result of lithium treatment be treated?
Levothyroxine
What type of drugs are sodium valproate, carbamazepine or lamotrigine?
Anti-convulsants
How do the anti-convulsant drugs work?
Block voltage sensitive sodium channels
Which anti-convulsant drug is the only one to be first line along with lithium in the longterm treatment of bipolar?
Sodium valproate
Anti-convulsants are mainly used for what type of treatment of bipolar disorder?
Long term prophylaxis (valproate can also be used for acute mania)
Do people with rapid cycling respond better to anti-convulsants or lithium?
Anti-convulsants
What are the side effects of sodium valproate?
GI upset, weight gain, sedation, tremor, dizziness
How often is sodium valproate taken a day?
Twice
What tests should be done prior to starting sodium valproate?
Platelet count and LFTs
What are the rules with sodium valproate and pregnancy?
Must not be used in pregnancy and only used in girls and women when there is no alternative and a pregnancy prevention plan is in place
What is the risk of sodium valproate in pregnancy?
Neural tube defects
What are the side effects of carbamazepine?
Drowsiness, ataxia, cardiovascular events
Can carbamazepine be used in pregnancy?
No
What are some side effects of lamotrigine?
Rash, GI upset, dizziness, ataxia
Which anti-convulsant has a risk of Stevens Johnsons syndrome?
Lamotrigine
How is the risk of Stevens Johnsons syndrome with lamotrigine reduced?
Titrate up very slowly
Which aspect of bipolar is lamotrigine better for?
Bipolar depression
