Table 2 The effect of vitamin C on acute and chronic viral-associated pain

Placebo controlled RCT

 Herpes Zoster [70]

i. Placebo infusion (N = 42)

i. 4.2 ↓ VAS, 57% PHN incidence

ii. 5 g IV vitamin C (N = 45) on days 1, 3, 5

ii. ≥5.6 ↓ VAS*, 31% PHN incidence* (at 8 and 16 week follow up)

 Postherpetic neuralgia [69]

i. Placebo infusion (N = 20)

i. 0.9 ↓ NRS, 10% PGIC

ii. 50 mg IV vitamin C/kg body weight (max dose 2.5 g/day) (N = 21) three times over 5 days

ii. 3.1 ↓ NRS*, 62% PGIC* (at 7 day follow up)

Uncontrolled prospective

 Herpes Zoster [68]

7.5 g IV vitamin C (N = 64) 2–4 times/week for 2 weeks

Baseline: 58% pain (VAS)

Week 2: 22% pain

Week 12: 6% pain

 Chikungunya virus—moderate to severe pain [75]

H₂O₂ + 25–50 g IV vitamin C (N = 56) single infusion

Before: 80% pain (NRS)

After: 20% pain, no pain in 9% of patients

Case report

 Parvovirus B19 viremia—chronic arthralgia [74]

i. 10 g/day oral vitamin C for 10 days

i. Before: 30% pain (VAS)

After: 5% pain

ii. 10 g/day oral vitamin C for 3 weeks

ii. Before: 40% pain (VAS)

After: 10% pain (at 3–5 week follow up,

there was↓ pain within 5 days)

 Chikungunya virus—severe joint pain [73]

100 g/day IV vitamin C for 2 days

Pain resolved within 24 h

 Refractory herpes zoster-associated pain [67]

4 g/day IV vitamin C for 5 days

Before: 70% pain (VAS)

After: 0% pain (at 3 month follow up)

 Herpes zoster—severe dermatological pain [66]

Cantharidin + 7.5 g IV vitamin C every 2 days for 2 weeks

Before: 80% pain (NAS)

After: 40% pain (within 2 weeks),

0% pain (at 8 week follow up)

 Acute herpetic neuralgia [65]

15 g IV vitamin C every 2 days for 12 days

Before: 80% pain (VAS)

After: 0% pain (within 8 days)

 Acute herpetic neuralgia [65]

15 g IV vitamin C every 2 days for 16 days

Before: 100% pain (VAS)

After: 0% pain (within 12 days)

 Postherpetic neuralgia [64]

2.5 g IV vitamin C every 2 days for 5 days

Before: 73% pain (NRS)

After: 0% pain (within 7 days and at 3 month follow up)