• terminal care
• clinical decisions
• drug administration
• end of life care
• pharmacology

Phenobarbital is a barbiturate medication used clinically for over 100 years for the treatment of seizures, for anaesthesia and more recently for palliative sedation.1 Its primary mechanism of action is through enhancing the postsynaptic inhibitory activity of Gamma Amminobutyric Acid-A(GABA-A) receptor by permitting more chloride influx, as well as blockade of excitation via glutamate signal. These mechanisms result in hyperpolarised neurons resulting in antiepileptic and sedative properties.1

Palliative sedation is the provision of relief of suffering for the terminally ill by the provision of sedative medications, including benzodiazepines and phenothiazine neuroleptics, and in refractory cases, barbiturates. The European Association of Palliative Care framework for sedation states that barbiturates are useful where patients are tolerant to other sedatives due to their differing mechanism of action and as a third-line sedative in the palliative setting if other options have been used.1 Doses are reported as typically within the 800–1200 mg per 24 hours range via continuous subcutaneous infusion (CSCI), but with significant variability up to 3800 mg/24 hours via CSCI,1 depending on loading doses required and symptomatic response.

In our centre, phenobarbital is used as a sedative …