Prochlorperazine

Recommendations

Type	Recommendation
When to deprescribe
CBR	We suggest deprescribing be offered to older people taking long-term prochlorperazine: Originally for a short-term indication (e.g. symptoms of acute vertigo typically resolve within hours to days); or With no clear or known indication; or For the indication of drug-induced nausea and vomiting/dizziness, where the original drug can be suitably reduced, discontinued, or replaced by another drug (e.g. inappropriate prescribing cascade)
Ongoing treatment
CBR	Given the harms of long-term prochlorperazine use are likely to outweigh the benefits in most cases, we generally suggest against the use of long-term prochlorperazine in older people and trial on-demand or intermittent use at the lowest effective dose in addition to appropriate investigation to identify and subsequently treat a cause. If symptoms are chronic and persistent, we suggest considering appropriate non-pharmacological therapies and/or safer alternatives for symptoms, provided this aligns with the individual's goals and preferences, following informed consent.
How to deprescribe
CBR	We suggest individualising the tapering schedule and adjusting it according to the individual's response. In general, given the likelihood of symptom recurrence in long-term users, we suggest reducing the dosing frequency every one to two weeks: For those on three times daily, reduce to twice daily, then once daily, then cease completely; or For those on twice daily, reduce to once daily, then cease completely and switch to on-demand or intermittent use at the lowest effective dose. If symptoms recur during tapering, we suggest restarting at the previously tolerated tapered dose until symptoms resolve, delaying further dose reductions by an agreed interval for stabilisation, and planning for a more gradual taper.
Monitoring
CBR	We suggest closely monitoring for disease exacerbations (e.g. symptoms recurrence) or adverse drug withdrawal events (ADWEs, e.g. withdrawal-emergent abnormal movements), every two weeks following each dose adjustment until at least four weeks after the medicine is fully ceased if practical. After this initial period, we suggest monthly monitoring for at least three months, followed by monitoring every six months thereafter. However, this should be tailored based on individual factors such as their preferences, responses and tolerance to deprescribing. For persistent ADWEs, we suggest collaborating with other relevant healthcare providers (e.g. physiotherapist and speech pathologist) to evaluate their impact and seriousness and develop strategies to resolve them. If in-person visits are impractical, we suggest informing people to report symptom recurrence (e.g. dizziness) and/or any appearance of new symptoms as needed.

CBR, consensus-based recommendation; GPS, good practice statement

Introduction

Prochlorperazine is a dopamine antagonist indicated for symptomatic relief of acute vertigo and to prevent or treat both nausea and vomiting [177]. Prochlorperazine and other anti-vertigo medications should be limited to acute use and administered for the shortest duration possible. Vestibular rehabilitation should be considered as part of the management plan where appropriate. Furthermore, people with benign paroxysmal positional vertigo would benefit from Epley manoeuvres as the first-line treatment. When performed by a trained healthcare provider, Epley manoeuvres can usually resolve symptoms [178].

Narrative summary of evidence on deprescribing

We were unable to identify any direct evidence related to the deprescribing of prochlorperazine in older people from the systematic review and meta-analysis. Recommendations are provided in this section following a Delphi consensus process.

Justification of recommendations

Long-term use of prochlorperazine to treat dizziness and vertigo is not recommended due to the potential sedative and hypotensive effects that may increase the risk of falls, especially in older people [177]. The risk of more serious side effects including extrapyramidal symptoms (usually acute dystonic reactions) increases with cumulative dose and length of treatment [177]. Extra caution is required for older people, particularly those with Parkinson’s disease where it is recommended to best avoid (Beers Criteria) [177, 179]. Prochlorperazine also causes many anticholinergic side effects including confusion, delirium, hallucinations, visual disturbance, urinary retention, constipation and tachycardia [180]. In older people, these may be severe and lead to cognitive impairment, falls and increased all-cause mortality [180]. Prochlorperazine is commonly initiated due to dizziness as a side effect of other medicines such as diuretics (i.e. a prescribing cascade) [181]. A significant association between cardiovascular medicines, NSAIDs, opioids and sedatives and the subsequent initiation of prochlorperazine has previously been reported [181]. It is crucial to identify dizziness as a potential side effect of other medicines before initiating treatment to avoid inappropriate prescribing cascades.

The tapering approach is based on pharmacological rationale and clinical experience, considering the possible recurrence of symptoms and the risk of withdrawal-emergent abnormal movements in long-term users.

Given the lack of deprescribing-specific evidence, the monitoring plan should be informed by known adverse effects associated with dopamine antagonists and the clinical consensus on safe withdrawal practices in older populations. ADWEs such as extrapyramidal symptoms may emerge during or after dose reduction and should be closely observed.

Note: While metoclopramide is part of the top 100 PBS medicines, it is not covered in this guideline as it is typically used short term (up to five days).