Bipolar Depression (Manic-Depression)

Bipolar Depression (Manic-Depression)

·        Affects 1%(Example Location : New Zealanders) of the population (35,000 New Zealanders)

·        Genetic predisposition:

o  No family history then risk is 1%

o  One parent then risk is 20%

·        Symptoms: 

o   Manic Phase: elation, pleasure, energy, racing thoughts, invincible, grandiose (­self esteem), irritable, aggressive, lack of judgement (eg reckless driving, spending sprees, sexual indiscretion)

o  Depressive Phase: same symptoms as for major depressive episode

·        History questions for mania:

o  How do you feel about yourself?

o  Do you feel that you are special?

o  Have you needed less sleep?

o  How much have you been spending lately

·        Classifications of Bipolar Depression 

o  Mixed Episode: rapidly alternating mood – at least 1 week in which the criteria are met for a manic episode and a MDE nearly every day

o  Bipolar 1: one or more manic or mixed episodes, usually accompanied by MDEs

o  Bipolar 2: one or more MDEs accompanied by at least one hypomanic episode 

o  Cyclothymia: At least 2 years of numerous periods of hypomanic symptoms and depressive symptoms that don‟t meet criteria for mania or MDE (cf Dysthymia)

·        Mood stabilising medication:

o  Lithium carbonate (requires regular blood tests.  Can they get to the lab?)

o  Carbamazepine (Tegretol)

o  Sodium Valproate (Epilim)

o  All have similar efficacy, Lithium most common 

o  Antipsychotic or tranquillising medication often added during early stages to reduce agitation and hyperactivity 

o  Antidepressant medication can be used during depressive phase (although therapeutic delay a problem), and withdrawn gradually when it resolves. If used in isolation without a mood stabiliser, may precipitate a manic phase as the depression lifts

·        Can be very stressful on relationships for family members

 Lithium

·        Indication: In bipolar, but also recurrent unipolar. Not good for acute mania – takes 2 – 4 weeks, full response may take 6 months

·        Pharmacokinetics: 

o  Variable absorption. T½ is 18 hrs in young, 26 hours in elderly. Excreted unchanged. 80% reabsorbed in proximal tubule 

o  Renal clearance of Li reduced by diuretics, NSAIDs, theophylline, caffeine, dehydration, low sodium 

o  Clearance related to tubular sodium load. If ­Na excretion (eg loop and thiazide diuretics) then ¯Li excretion. 

o  ACE inhibitors ®­Li levels

·        Monitoring:

o  Narrow therapeutic range for maintenance treatment: 0.4 – 0.8 mmol/l 

o  Therapeutic drug monitoring for Li is mandatory when: side effects, relapse of symptoms, serious illness (eg dehydration), dose adjustment

o  Check thyroid and renal function before starting

o   Monitoring every three months should include Li levels, electrolytes, thyroid function 

o   Monitor 12 hrs after immediate release, 5 hrs after slow release. Slow release preparations prevent peaks in plasma conc. (® nausea, headache)

·        Side Effects:

o   Minor symptoms such as tremour and nausea do not predict serious toxicity:

§  Tremor (especially elderly), nausea, loose bowel motions (especially if levels > 0.8 mmol/L)

§  Polyuria (especially when starting)

§  Weight gain: approx 4 kg

§  Pretibial oedema

§  Metalic taste

o   Dose dependent adverse effects:

§  1.5 – 3 mmol/l – ataxia, weakness, drowsiness, thirst, diarrhoea

§  3 – 5 mmol/l – confusion, spasticity, convulsions, dehydration, coma, death 

o   Dose independent: hypothyroidism (reversible in early stages), nephrogenic diabetes insipidous, ECG changes & arrhythmias, acne, GI disturbance, weight gain, ¯bone calcium 

o   Long term Li does not change GFR or lead to renal failure