Transcript Pharmacotherapy of Functional Mental Illness in the Elderly

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
Pharmacodynamics in the Elderly
• Drug interactions
• Narrower therapeutic window – side
effects/toxicity
• Treatment resistance - reduction in
receptor density
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), antiparkinsonian (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
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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 48-72 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%), 10-20 % of adult
antipsychotic doses, good prognosis.
Thank you