Mood Stabilisers Flashcards
Name 5 Mood Stabilisers (including brand names)
- Lithium
- Sodium Valproate (Epilim)
- Semi-Sodium Valproate (Depakote)
- Carbamazepine
- Lamotrigine
What are the different Mood Stabilisers indicated for?
- Lithium; Bipolar disorder, cyclic mood disorder
- Sodium Valproates, Carbamazepine and Lamotrigine;
- anticonvulsants-treatment and management of Epilepsy
- prophylaxis or adjunct therapy of Bipolar
What is believed to be the mechanism of action for Lithium?
- Lithium is a naturally occuring salt/mineral
- Works on CNS to improve nerve cell communication-not exactly sure how?
- May alter NA transport in nerve and muscle cells, thus affecting excitability
- Changes in gene expression?
- May decrease levels of 2nd messengers (such as cAMP) inside neuron-this could allow it to selectively modulate responsitiveness of hyperactive neurons that might contribute to manic state)
- Recent theory that this occurs by activating the CRMP2 protein which is responsible for nerve cell communication.
- Despite not knowing how, it does work in 1/3 of patients!
What is the general mechanism of action of the anti-convulsant mood stabilisers?
- Reduce abnormal electrical activity in brain via
- inhibition of voltage-sensitive Na+ channels leading to
- reduced influx of Na+ ions, preventing
- neurons from depolarisation and therefore generation of Action Potential
- These can be ‘use-dependent’-more effective at blocking channels in areas of the brain where action potentials are firing repetitively
How else does Carbamazepine work?
- (other than stabilisation of neuronal membranes via inhibition of voltage-sensitive ion channels)
- has the ability to inhibit polysynaptic responses?
How else does Lamotrigine work?
- It also inhibits the Ca+ dependent presynaptic release of excitatory NTs such as glutamate
- Newer!
How else do the Sodium Valproates work?
Indirectly by increasing GABA activity. GABA is an inhibitory NT (think Benzos)-Cl ions, hyperpolarisation, inhibit neuronal transmission, reduced chance of AP, exerts stabilising influence, thereby decreasing excessive activity
They do this by;
- enhancing availability of GABA in synaptic cleft
- through inhibition of 2 enzymes responsible for GABA inactivation
- enhancing postsynaptic action of GABA
- through enhancing opening of receptors
What are the contraindications common to all mood stabilisers?
- Pregnancy
- Renal Impairments
- Suicidal thoughts
What are the contrainidications for Lithium?
- Cardiovascular disease
- Hyperthyroidism
- Addison’s/Brigada Disease
- ECT
- Diuretics or people with sweating/diarrhoea
What are the contraindications for the Sodium Valproates?
- MAOIs or APs
- Hepatic dysfunction
What are the contraindications for Carbamazepine?
- Chemically related to TCAs, so not if allergic
- Many drug interactions (TCAs, MAOIs, APs, other anti-seizure drugs)
- St John’s Wort
- decrase oral contraceptive efficacy
- Heart Conditions
- no alcohol
- no grapefruit
What are the contraindications for Lamotorgine?
- Parkinsons
What are the side effects of lithium?
adverse effects linked to serum levels
- Tremors
- Weight gain
- GI upset-constipation/diarrhoea
- Polyuria/polydipsia
- metallic taste
What are the side effects common to anticonvulsants generally?
- Indicators of disorders of
- Blood (anaemia, bone marrow suppression)
- Liver (hepatitis)
- Skin (Stevens-Johnson syndrome)
- GI disturbances
- Fatigue
What are the additional side effect of the Sodium Valproates?
- Weight Gain
- Hair Loss
