Prescribing in Old Age Psychiatry

Patients who are over the age of 65 with mental health needs are seen by the Older Age Psychiatry services, which cover inpatient, outpatient, and liaison services. This service was created to address the unique needs and characteristics of this population. The older adult population often have co-occurring comorbidities and polypharmacy as a result. This poses numerous challenges for the psychiatry team, with a careful balance required for their physical and mental health. Some younger patients can be referred to the service if they have underlying frailty or cognitive impairment and may benefit from the Older Age ward environment and/or clinical expertise.

Principles of prescribing

The general prescribing principle from both Old Age Psychiatrists and Geriatricians is to start at a low dose for a drug, and then titrate up slowly. A small dose for a general adult patient may be large than for an elderly patient, owing to co-existing factors such as low body mass index (BMI), kidney disease, liver disease, and polypharmacy. Medication choice should also be dictated by likely compliance, especially in light of cognitive impairment leading to unintentional overdose or suicidality. These patients often have a high pill burden and so like in a general hospital, can benefit from medicine reconciliation and optimisation. One way to do this can be by prescribing a modified release single dose of psychiatric medication, as opposed to repeated shorter-acting preparations. 

Additionally, it is better to practice to initiate one drug at a time, thus removing the ambiguity of the origin of drug side effects and interactions when they do occur. In summary, ‘start one low and go slow’. 

The following article is summarised from national references, and any recommendations should be drawn from local guidance, individual Trust policy, and in collaboration with pharmacy input. 


Serotonin Reuptake Inhibitors (SSRIs) and Serotonin Noradrenaline Reuptake Inhibitors (SNRIs)

  SSRIs are commonly prescribed across the globe for the treatment of affective disorders, as well as in Older Age Psychiatry for the Behavioural and Psychological Symptoms of dementia (BPSD). These drugs have a few notable benefits, side effects and contraindications, which are outlined in the table below. The main considerations before choosing which SSRI to initiate in Older Age Psychiatry are the length of the QT interval, bleeding risk (particularly gastrointestinal) and potentially interacting medications. 

 SNRIs are usually the second line after SSRIs for the treatment of affective disorders and BPSD. The most common SNRI prescribed is Venlafaxine due to its large research base for numerous affective disorders (major depression, generalised anxiety disorder). Duloxetine is another SNRI that is used for affective disorders and other conditions, such as fibromyalgia and stress urinary incontinence. 

DrugRecommended Avoid/caution Side EffectsCautionsContraindicationsInteractions
SSRIs-Sertraline (1st line especially in pre-existing cardiovascular disease)
-Citalopram
-Escitalopram
-Paroxetine, avoid due to the highest anti-cholinergic burden

-Fluoxetine, caution due to long half-life and prolonged side effects
-Increased bleeding risk (GI)
-Sexual dysfunction
-Transient increased suicidality and anxiety
-SIADH
Cardiac disease
History of bleeding disorders.
Acute angle-closure glaucoma
Current Electroconvulsive therapy
Hyponatraemia
-Mania
-Poorly controlled epilepsy
-Long QT
Bleeding- NSAIDs, anticoagulants, Aspirin.
Serotonin syndrome- triptans, Monoamine oxidase inhibitors (MOAIs)
SNRIs-Venlafaxine
-Duloxetine (also beneficial for neuropathic pain)
-Hypertension
-Anxiety
-Long QT
-Sexual dysfunction
-Tremor
-Cardiac arrhythmias
-Heart disease
-Bleeding disorders
-Epilepsy (lowers seizure threshold)
-Previous mania
-Acute angle closure glaucoma
Cardiac arrhythmias
Heart disease
Bleeding disorders
Epilepsy (lowers seizure threshold)
History of mania
Acute angle closure glaucoma
-Mania
-Poorly controlled epilepsy
-Long QT
Bleeding- NSAIDs, anticoagulants, Aspirin.
Serotonin syndrome- triptans, Monoamine oxidase inhibitors (MAOIs)
Long QT-Amiodarone, Apomorphine


Antipsychotics

 Antipsychotics possess clinical efficacy to treat psychosis in elderly patients, as well as having a role in some elements of the behavioural and psychological symptoms of dementia (BPSD), however, they pose a higher risk of morbidity and mortality in this patient group. These drugs have been commonplace in a general hospital for patients with dementia who are in distress, but evidence now suggests these drugs do very little to reduce behaviours such as calling out and pacing, instead causing a variety of side effects. The advice for use in dementia patients currently is to only use if aggressive, with a risk to themselves or others, or if distressing hallucinations or delusions occur for the patient. Regular reviews should occur to keep the dose at the lowest therapeutic level or to stop the drug if able to. This group of drugs has an extensive list of side effects recorded in the BNF, with not all listed, so please consult the BNF for more information.

Features1st Generation ‘Typicals’2nd Generation ‘Atypicals’3rd Generation
Examples usedChlorpromazine
Haloperidol Zuclopenthixol
Risperidone
Olanzapine
Quetiapine
Aripiprazole
MechanismD2 receptor antagonistD2 and 5HT2A receptor antagonistsPartial dopamine agonist (D2 and D3)
Side effects-Highest risk of Extrapyramidal side effects (EPSEs)
-Hyperprolactinaemia
-Higher risk of Metabolic e.g. weight gain, diabetes mellitus
-reduced bone mineral density
-Increased risk of stroke and mortality
-Lower risk of Extrapyramidal side effects (EPSEs)
-Higher risk of Metabolic e.g. weight gain, diabetes mellitus
-Increased risk of stroke and mortality
-Less sedating
-Rare to cause hyperprolactinaemia
-Increased risk of stroke and mortality
-Risk of falls
ContraindicationsCNS depression
Long QT or history of torsades de pointes
Lewy Body dementia
Parkinson’s disease and Parkinson’s plus syndromes
Recent Myocardial infarction
Heart failure
Hypokalaemia
Acute Myocardial infarction
Bradycardia
Sick sinus syndrome
Unstable angina
CautionsParkinson’s disease
Lewy Body Dementia
Epilepsy
Blood dyscrasias
Cardiovascular disease
Diabetes
Increased risk of stroke
Parkinson’s disease
Lewy Body Dementia
Epilepsy
Blood dyscrasias
Cardiovascular disease
Diabetes
Increased risk of stroke
Parkinson’s disease
Lewy Body Dementia
Epilepsy
Blood dyscrasias
Cardiovascular disease
Diabetes
Increased risk of stroke
Lithium

 Lithium is the treatment of choice for maintenance therapy for bipolar affective disorder (BAD), as well as having uses in mania and recurrent depression. This drug is complex owing to it being renally excreted, with renal impairment being commoner in the elderly population. Lithium requires close monitoring with regular blood testing (taken 12 hours after the dose) due to its narrow therapeutic window. At initiation renal, cardiac and thyroid function and body mass index are measured. This is an unsuitable drug for an elderly patient with potential compliance issues (such as short-term memory impairment), so a psychiatric review should be sought with a view to switching to an alternative medication or an alteration in care or environment to facilitate supervised doses and monitoring. Frequent reviews are conducted to assess the benefits and risks of therapy and to monitor for side effects such as hypothyroidism, conduction abnormalities, and electrolyte disturbance. This is an uncommonly prescribed drug in this age group and would be reserved for those with intact cognition and reasonable physical health.

Memory Agents

 Commonly prescribed in the context of dementia are three drugs used to slow the progression of cognitive impairment. These three drugs are Donepezil and Rivastigmine, which are Acetylcholinesterase inhibitors, and Memantine, an NMDA receptor antagonist. Broadly speaking, either of the two former drugs is used in mild to moderate disease, and Memantine is used for later and more severe stages. These drugs are given orally, except for Rivastigmine which is available as a patch, which is ideal for patients with difficulty swallowing tablets. These agents are not without their cholinergic side effects, which are documented in the table below. In the elderly, these medications are used with caution owing to notable side effects, such as falls. These medications are also not just utilised in Alzheimer’s dementia, but in other forms of dementia and also following traumatic brain injury.

DrugMechanismSide effectsCautionsContraindicationsInteractions
DonepezilAcetylcholinesterase inhibitorAgitation
GI upset
Syncope
Incontinence
Bradycardia
GI Bleeding
Falls
Nightmares
Bladder outflow obstruction
Asthma/ COPD
Conduction defects
GI ulcers
Hepatic impairment
Epilepsy
Long QT interval
Bradycardia
Sick sinus syndrome
Drugs that slow heart rate e.g. beta blockers, calcium channel blockers
RivastigmineAcetylcholinesterase inhibitorAnxiety
Arrhythmias
GI upset
Syncope
Incontinence
AV Block
Falls
Nightmares
Bladder outflow obstruction
Asthma/ COPD
Conduction defects
GI ulcers
Hepatic impairment
Epilepsy
Long QT interval
Bradycardia
Sick sinus syndrome
Drugs that slow heart rate e.g. beta blockers, calcium channel blockers
MemantineNMDA (N-Methyl-D-Aspartate) receptor antagonistImbalance
Syncope
Sedation
Hypertension
Thromboembolism
Seizures
Ischaemic heart disease, untreated hypertension, previous cerebrovascular accidentIschaemic heart disease, untreated hypertension, previous cerebrovascular accidentAmantidine (severe)
Increases effects of Parkinson’s medications e.g. levodopa, bromocriptine



Take-home messages

-A risk versus benefit discussion should be had for each medication, with the least restrictive options considered and attempted first, for example, one-to-one nursing care for agitation in an inpatient setting.
-Consultation with an Older Age Psychiatrist or Geriatrician is advisable if you are concerned regarding a change in the physical health or mental health of an Older Adult patient already commenced on a psychotropic agent.
-It is safest when possible to initiate one drug at a time, at a low dose to monitor for potential side effects or toxicity.
-The STOPP START Tool is a useful tool to identify indications to review medication, with the aim of reducing polypharmacy and potential adverse effects in this population.
-Utilise the multidisciplinary team (MDT) prior to initiating, stopping or altering the dose of medication when possible for advice, such as your Ward Pharmacist and nursing colleagues.
-Antipsychotics are not beneficial for certain behavioural and psychological symptoms of dementia, such as pacing and calling out.

References

References:
British National Formulary (BNF), National Institute for Health and Care Excellence (NICE), Treatment summaries: Psychoses and related disorders
-The Maudsley prescribing guidelines in psychiatry (13th ed.), David Taylor, Thomas R Barnes & Allan H Young, John Wiley & Sons 2018.
-STOPP/START criteria for potentially inappropriate medications/potential prescribing omissions in older people: origin and progress. Denis O’Mahony, Expert Review of Clinical Pharmacology 2020.
– Old Age Psychiatry training packs, Royal College of Psychiatrists
-Optimising prescribing practices in older adults with multimorbidity: a scoping review of guidelines. Lun Penny Law, Felicia Ho, Esther Tan et al, BMJ Open Access 2021.

Written by Dr Isobel Platt, FY1
Edited by Dr Gareth Smith, Consultant Psychiatrist

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