Analgesia in liver failure

There hasn't been a CRQ specifically on analgesia in liver disease, though pharmacological aspects of previous questions involving liver disease have been poorly answered.

The majority of the information comes from the British Assocation for Study of the Liver Guide (see link below), although the authors themselves note "evidence in this field is limited, and suggested doses and dosing intervals are based largely on expert opinion".

Resources

Symptom Control and End of Life Care in Adults with Advanced Liver Disease (BASL, 2019)

Drug	Dosing
Paracetamol	Up to 3g in 24hrs PO Can do 4g/24hrs PO for short periods (<7 days) if weight >50kg Up to 3g in 24hrs IV Avoid IV whenever possible and reduce dose
NSAIDs	Avoid due to risk of bleeding and nephrotoxicity

Anti-neuropathic agents

Both gabapentin (100mg PO BD) and pregabalin (50mg PO BD) have reduced starting doses and require monitoring for excess sedation, but can otherwise be uptitrated as normal
Amitriptyline should be avoided

Whenever opioids are used monitor the patient closely for constipation and worsening encephalopathy

Drug	Dose
Tramadol	Avoid due to 2x ↑ t_1/2 & lower seizure threshold
Codeine	Use oral morphine preferentially 15 - 30mg PO TDS
Morphine sulphate	1^st line if eGFR ≥30 2.5mg 4 - 6hrly PO PRN
Hydromorphone	1^st line if eGFR ≤30 1.3mg 8hrly PO PRN
Oxycodone	Ideally avoid as ≥3x ↑ t_1/2 1.25mg 6 - 8hrly PO PRN

Commonly used perioperative anti-emetics should have their frequency and/or dose reduced, e.g.:

Ondansetron 4mg BD (max 8mg in 24hrs)
Cyclizine 25mg (IV) - 50mg (PO) BD
Metoclopramide 5mg TDS
Droperidol 0.625mg TDS
Domperidone 5mg PO BD

Others should either be used with caution (promethazine, aprepitant) or avoided entirely (prochlorperazine)