What is the oral dose of Nozinan (levomepromazine) used as needed (prn) for agitation in a general adult patient?

Oral Nozinan (Levomepromazine) PRN Dosing for Agitation in Adults

For oral levomepromazine PRN in agitated adults who can swallow, there is no established oral PRN dosing regimen in the available guidelines—levomepromazine is primarily recommended via subcutaneous route for delirium with agitation, not as an oral PRN agent for simple agitation. 1

Clinical Context and Guideline Recommendations

The NICE guidelines specifically address levomepromazine only in the context of delirium in patients unable to swallow, where it is given subcutaneously at 12.5-25 mg as a starting dose, then hourly as required (6.25-12.5 mg in elderly patients). 1 This is notably different from your clinical scenario of oral PRN dosing for general agitation.

What Guidelines Actually Recommend for Oral Agitation Management

For adults with agitation who can swallow, NICE guidelines recommend: 1

• Lorazepam 0.5-1 mg orally four times daily PRN (maximum 4 mg/24 hours)
• Reduced to 0.25-0.5 mg in elderly or debilitated patients (maximum 2 mg/24 hours)
• Oral tablets can be used sublingually if needed 1

For delirium with agitation in patients who can swallow, the recommendation is: 1

• Haloperidol 0.5-1 mg orally at night and every 2 hours PRN
• Maximum 10 mg daily (5 mg daily in elderly patients)
• Consider higher starting dose (1.5-3 mg) if severely distressed or causing immediate danger 1

Levomepromazine's Actual Role

Levomepromazine is positioned as a second-line agent for delirium when patients cannot swallow, not as a first-line oral PRN for simple agitation. 1 The ESMO oncology guidelines list oral levomepromazine (methotrimeprazine) at 5-12.5 mg PO or SC stat, with PRN dosing of 5-12.5 mg PO/SC every 2 hours PRN for delirium management, using lower doses (2.5 mg) in older or frail patients. 1 However, this is specifically for delirium in cancer patients, not general agitation.

Important Safety Considerations for Levomepromazine

• Sedating with significant anticholinergic effects 1
• May cause extrapyramidal side effects, orthostatic hypotension, and paradoxical agitation 1
• Subcutaneous injection may cause local irritation 1
• Limited evidence base for schizophrenia treatment, with available data insufficient to confidently comment on effectiveness 2

Clinical Algorithm for Oral PRN Agitation Management

Step 1: Address reversible causes first 1

• Hypoxia, urinary retention, constipation
• Ensure effective communication and orientation
• Optimize environmental factors (lighting, noise)

Step 2: Choose appropriate oral PRN based on clinical presentation 1

• For anxiety-driven agitation: Lorazepam 0.5-1 mg PO PRN (0.25-0.5 mg in elderly)
• For delirium with agitation: Haloperidol 0.5-1 mg PO PRN every 2 hours
• For severe distress or immediate danger: Haloperidol 1.5-3 mg PO as higher starting dose

Step 3: If considering levomepromazine specifically 1

• Use 5-12.5 mg PO every 2 hours PRN (2.5 mg in elderly/frail)
• Reserve for delirium cases where other agents have failed
• Monitor closely for sedation and hypotension

Critical Prescribing Pitfalls

• Do not use levomepromazine as first-line oral PRN for simple agitation—benzodiazepines are preferred and have better evidence 1, 3
• Avoid in Parkinson's disease or Lewy body dementia due to extrapyramidal side effect risk 1
• Approximately 50% of psychiatric inpatients receive PRN medications, but overuse is associated with increased morbidity, dependence, and polypharmacy 4
• Benzodiazepines should be first-line for acute agitation because they avoid the serious side effects common with traditional antipsychotics 3