Pharmacotherapy of Functional Mental Illness in the Elderly. Virupakshi Jalihal Locum Consultant Psychiatrist Cornwall Partnership NHS Foundation Trust 20 June 2011

Prevalence of many illnesses increases with age Generalisation of evidence to the elderly patients - Elderly individuals often excluded in trials

Pharmacokinetics in the Elderly Bioavailability - absorption may be poor Increased half life - altered metabolic rate and reduced renal clearance Volume of distribution - protein binding Increased concentration in brain – less efficient blood brain barrier

Drug interactions Narrower therapeutic window – side effects/toxicity Treatment resistance - reduction in receptor density Pharmacodynamics in the Elderly

Choice of Psychotropic Medication Presence of coexisting physical illness and/or cognitive impairment Previous response in the individual and family members Patient preference Clinicians familiarity Adequate dose and duration of treatment Start low and go slow

Depression Medication associated - psychotropic (benzodiazepine & buspirone), anti- parkinsonian (L-dopa & anticholinergics), anticonvulsant (carbamazepine & phenobarbitone), antihypertensive (methyldopa & Beta blocker), NSAID, steroids, etc..,

Depression Response may take longer – up to 12 wks SSRI, SNRI, NARI, NaSSA are preferred – less sedation, postural hypotension, anticholinergic side effects. Safer cardiac profile and in overdose, lesser effect on seizure threshold TCA – 2/3 line, anticholinergic side effects, lofepramine is preferred TCA MAO inhibitors – 2/3 line, Moclobomide is reversible MAOI & preferred. Remember washout period if switching, MAOI->SSRI is 2 wks & SSRI-> MAOI can be up to 5 weeks.

Depression Augmentation – lithium in treatment resistance ECT – severe depression with psychotic symptoms and/or psychomotor retardation.

Bipolar Affective Disorder Increase in frequency & duration of episodes Drug induced - steroids Mood stabiliser or antipsychotics Atypical antipsychotics preferred Decreased GFR – risk of lithium toxicity Lithium dose may be lower than in adults – aim for 0.5 mmol/L Valproate may be preferred

Psychosis Rule out delirium Paraphrenia or schizophrenia Paraphrenia needs lower dose of antipsychotic medication Atypical antipsychotics preferred Clozapine is still an option in the elderly Avoid drugs with anticholinergic action – phenothiazines Tardive dyskinesia is difficult to treat

Neurotic disorders Anxiety symptoms common in the elderly Benzodiazepines commonly used – be aware of dependence potential and paradoxical agitation Buspirone – 5HT1a receptor, less side effects but is it effective? SSRI in OCD, phobia, panic disorder Beta blockers for anxiety Combine pharmacotherapy with psychological approaches.

Insomnia & Sexual dysfunction Insomnia is common Use hypnotics judiciously Sildenafil is an option for erectile dysfunction

Miscellaneous Treatment of coexisting physical and organic conditions Pharmacotherapy of drug and alcohol dependence Aids to improve compliance Psychotropics in palliative care Withdrawal of medication in those dying

MCQ/BOF 1.Drug that increases lithium level is (a) Furosemide (b) Propronolol (c) Paracetamol (d) Mirtazapine (e) Salbutamol Ans:Lithium levels are increased by diuretics except for acetazolamide. Loop diuretics (furosemide) are safer than thiazides.

2. A patient has been on antidepressant but he forgets to take his tablets once or twice in a week. Which of the following is more suitable for him? (a)Fluoxetine (b)Venlafaxine (c)Duloxetine (d)Sertraline (e)Paroxetine Ans:Fluoxetine has a half-life of hours, its active metabolite norfluoxetine has a half-life of about a week. This will mean slower tapering of plasma levels if 1 or 2 doses are missed thus avoiding withdrawal symptoms. Some even suggest that fluoxetine can be administered biweekly or on alternate days.

3. Which of the following is a noradrenaline reuptake inhibitor (NARI)? (a) Reboxetine (b) Paroxetine (c) Fluoxetine (d) Risperidone (e) Agomelatine Ans:Maprotiline, viloxazine and reboxetine are selective noradrenaline reuptake inhibitors.

4. Use of which drug would require a lower dosage of ECT? (a) Lithium (b) Zolpidem (c) Valproate (d) Lamotrigine (e) Diazepam Ans: Lithium can decrease the seizure threshold and the patient may have increased seizure duration. All others tend to increase seizure threshold and require higher dose of ECT to produce an adequate seizure.

5. A depressed patient with a history of CVS problems was started by his GP on fluoxetine. After few days of treatment he started complaining of feeling lethargic with muscle aches, and malaise. What is the likely cause? (a) Hyponatraemia (b) Myocardial infarction (c) Delirium (d) Heart failure (e) Anaemia Ans: Hyponatraemia is associated with SSRI treatment especially in elderly patients. Confusion, agitation and lethargy are common symptoms.

6. Which of the following is true regarding paraphrenia? (a) More common in males (b) Associated with schizophrenia (c) Rarely seen in the elderly (d) Need high doses of antipsychotis (e) Has good prognosis Ans: Onset usually >60 years, more common in females (up to 80%), % of adult antipsychotic doses, good prognosis.

Thank you