Adjuvant Analgesics
| Class of drugs | Indication | Example | Adverse effects/comments |
|---|---|---|---|
| Non-steroidal anti- inflammatory drugs (NSAIDs) | Inflammation Bone metastases Soft tissue infiltration | Individual drug choice based on patient's risk factors and adverse effect profile of drug Use PPI cover | Peptic ulceration, bleeding and perforation Arterial thrombosis Renal impairment Fluid retention Avoid in elderly |
| Steroids | Inflammation Soft tissue infiltration Bone metastases Nerve compression Liver capsule pain Raised intracranial pressure | Dexamethasone (4–8 mg daily, morning dose to reduce insomnia) Titrate down to lowest dose that controls pain Short course with PPI cover | GI irritation and bleeding Fluid retention Cushingoid appearance |
| Anti-muscarinics | Smooth muscle colic | Hyoscine butylbromide | Dry mouth, constipation, urinary retention, blurred vision, flushing, tachycardia |
| Bisphosphonates | Painful bone metastases | Various regimens (usually IV infusion) | Flu-like symptoms Osteonecrosis of the jaw (need dental review before commencing) |
| Neuropathic agents | |||
| Gabapentin | Neuropathic pain (Anticonvulsant) | 300 mg PO with starting dose at night and titrate by 300 mg/24h every 2–3 days (Slower titration in elderly/frail: 100 mg at night and titrate by 100 mg/24h every 2–3 days) | Mild sedation Tremor Confusion Reduce dose in renal impairment |
| Pregabalin | Neuropathic pain (Anticonvulsant) | 75 mg 12-hourly PO starting dose and titrate at intervals of 3–7 days,in debilitated patients start with 25 –50 mg BD. | Dizziness, drowsiness (usually improve) Confusion, tremor, dry mouth Reduce dose in renal impairment |
| Amitriptyline | Neuropathic pain (antidepressant) | 10 mg PO with starting dose at night and titrate up after 3–7 days if tolerated | Sedation, dizziness, confusion, dry mouth, constipation, urinary retention Caution in heart failure |