Table 22

Morphine sublingual

Morphine sublingual
What is it?Opioid analgesic
Mechanism of actionMu opioid receptor antagonist
Starting dose2.5 mg given as drops, up to hourly
Time to effectUncertain (16–60 min oral, but drug not lipophyllic therefore likely to be significantly longer)17
Formulation20 mg/1 mL oral solution, designed for oral administration, risk of unpredictable absorption
OR injection
IndicationPain, breathlessness
Common adverse effects‘Appetite decreased; asthenic conditions; gastrointestinal discomfort; insomnia; neuromuscular dysfunction’16
Contraindications‘Acute abdomen; delayed gastric emptying; heart failure secondary to chronic lung disease; phaeochromocytoma’16
CautionSee for Drug Driving advice
Licencing‘Off label’ route of licensed oral solution; ‘off label’ route of licensed injection
BenefitsA transmucosal alternative to oral or subcutaneous morphine
RisksBest avoided due to unpredictability of bioavailability when buccal route used, likely lower than oral due to solution not being lipophilic, likely no advantage over oral administration
Cost£19.50 for 120 mL x 20 mg/mL oral solution; £11.47 for 10×10 mg/mL ampoules for injection