Overview

To assess the 1-week effects and safety of esketamine in combination with pregabalin and duloxetine to relieve pain in patients with postherpetic Neuralgia(PHN).

Eligibility

Inclusion Criteria:

1. Ages more than 18 years;
2. Pain present for more than 3 months after healing of a herpes zoster skin rash;
3. Has an average pain score of at least 4 on a Numeric Rating Scale (NRS, 0= no pain, 10= worst possible pain)；
4. Failed to respond to or tolerate the effective dose of pregabalin monotherapy.

Exclusion Criteria:

1. Obstructive sleep apnoea syndrome;
2. Those who receive interventional treatments;
3. A history of systemic immune diseases, organ transplantation, or cancers;
4. A history of severe cardiopulmonary, hepatic or renal dysfunction;
5. A history of schizophrenia, epilepsy, or myasthenia gravis, delirium;
6. Currently using monoamine oxidase inhibitors (MAOIs);
7. Having untreated angle-closure glaucoma;
8. Those suffering from increased intracranial pressure；
9. Comorbid hyperthyroidism or phaeochromocytoma;
10. Suspected or confirmed history of drug abuse;
11. Having contraindications to esketamine, pregabaline or duloxetine;
12. Communication difficulties;
13. Women who are preparing for pregnancy, in the pregnancy or lactation period.