Levomepromazine
Class: antipsychotic/neuroleptic – phenothiazine
Indications (NB some may be unlicensed): psychosis, severe ‘terminal’ pain with anxiety/distress/restlessness, schizophrenia, with other analgesics for pain, anxiety and distress, nausea/vomiting in palliative care
Contraindications/cautions: hepatic dysfunction, encephalopathy, Parkinson’s disease, DLB
Adverse reactions: common: dry mouth, somnolence, postural hypotension, sedation; less common: hypotension, extrapyramidal side effects (long term high dose usually)
Metabolism/clearance: metabolised by sulphonation then glucuronidation. Metabolites may be active and are excreted by the kidneys so care in renal dysfunction. May inhibit CYP2D
Interactions:
- increased clinical effect/toxicity of some drugs (due to increased blood concentrations of them) may occur with levomepromazine due to metabolising enzyme inhibition by levomepromazine e.g. amitriptyline, codeine (decreased morphine concentrations so decreased clinical efficacy of codeine), fluoxetine, nortriptyline, oxycodone, paroxetine, promethazine
- additive CNS effects with other CNS depressants e.g. benzodiazepines (e.g. lorazepam), other phenothiazines (e.g. chlorpromazine), tricyclic antidepressants (e.g. amitriptyline), opioids, alcohol
- additive increased risk of QT interval prolongation (cardiac adverse effect which may lead to arrhythmias) with tricyclic antidepressants (e.g. amitriptyline), flecainide, erythromycin, theophylline, domperidone
| Dosing: | ||
|---|---|---|
| pain, restlessness, distress, delirium | nausea/vomiting | |
| oral: | 6.25 to 50 mg every 4 to 8 hours | 6.25 to 12.5 mg daily |
| subcut: | 6.25 to 200 mg/24 hours | 6.25 to 12.5 mg/24 hours |
| rectal: | not available | not available |
Syringe driver: see syringe driver compatibility chart
Mechanism of action: suppresses sensory impulses in the CNS via various neuro- transmitters
Onset: im/subcut (analgesia): 20 to 40 minutes
Duration: im/subcut: 12 to 24 hours Half life: 15 to 30 hours
Notes:
- only phenothiazine with analgesic properties
- D2, 5HT alpha adrenergic, H1 and muscarinic antagonist
- doses of less than 25 mg/24 hours are associated with minimal sedation
- benztropine 2 mg may be useful in alleviating extrapyramidal side effects
- may be a useful option in patients with multiple symptoms
- only available as a 25 mg tablet – quarter of a tablet = 6.25 mg for nausea
- for smaller doses disperse tablets in water and give a fraction of it