Amitriptyline for the prevention of post-herpetic neuralgia
Shingles
Amitriptyline 10 mg tablets (or matched placebo tablet), increasing in 10 mg steps over 2 weeks as tolerated, to 30 mg maximum per day, for 70 days. Total follow-up is 12 months, with participant surveys at baseline and 30, 60, 90, 120, 180 and 360 days after rash onset. Randomisation: Trial participants will be allocated in a 1:1 ratio to receive amitriptyline or placebo. Randomisation will be stratified by centre and minimised on age deciles, gender at birth, pain in the last 24 hours and shingles vaccination history. The randomisation sequence will be generated by the company Sealed Envelope™ using their online randomisation system, which will allocate the participant to a treatment arm. The person undertaking the randomisation and the participant will remain masked as to which treatment group this code refers.
1. Adults aged ≥50 years 2. Clinical diagnosis of herpes zoster (HZ) 3. Rash onset <144 hours
1. Inability to give informed consent 2. Third or more episode of herpes zoster 3. Known adverse reaction to amitriptyline or contraindications (monoamine oxidase inhibitors) 4. Current/recent (within previous two weeks) use of a tricyclic antidepressant 5. Prolonged QT interval or concomitant drugs that prolong the QT interval 6. Suicidal ideation 7. Heart block 8. Recent myocardial infarction (<4 weeks) 9. Immunosuppression 10. Significant bradycardia 11. Uncompensated heart failure 12. Hyperthyroidism 13. Severe liver disease 14. Phaeochromocytoma 15. Urinary retention 16. If female; current or planned (in next 3 months) pregnancy or breastfeeding 17. Currently (or recently, within the previous 4 months) enrolled in another CTIMP