Background

Mucositis can cause severe acute pain and may be opioid refractory. 

 

Aims 

To evaluate ketamine’s efficacy versus placebo in managing treatment-related oral and pharyngeal mucositis pain.

 

Mucositis patients with an average pain score of ≥ 4 (Brief Pain Inventory) received ketamine plus midazolam 5 mg or placebo plus midazolam 5 mg via subcutaneous infusion over 24 hours for 3 to 5 days. Ketamine dosage was escalated from 100 to 300 mg/24 hours in 100 mg increments. Clinical pain response indicated at least a 2-point reduction in average pain score from baseline without over four breakthrough analgesic doses in 24 hours. A linear mixed-effects model was used for repeated measures data and sample size calculation, requiring 18 patients to achieve 80% power. Fisher’s Exact test was used. Baseline data, pain scores, and medications were recorded. 

 

A preliminary analysis of 14 participants was performed. The pain response rate was 75 % (6 of 8) in the ketamine and 0% (0 of 6) in the placebo groups, with a significant difference (P=0.009). The mean average pain score significantly decreased from 6.25 to 2.00 (95%CI, 0.62 to 3.39) and 7.17 to 6.00 (95%CI, 4.87 to 7.13) in ketamine and placebo groups, respectively; P=0.019. The mean worst pain in ketamine group decreased from 8.13 to 3.20 (95%CI, 1.11 to 5.30) compared to 8.50 to 7.33 (95%CI, 6.69 to 7.98) in placebo group;P=0.031. The mean morphine daily dose was significantly lower in the ketamine group (P=0.027). Ketamine improved functional oral intake (P=0.031) and yielded a 50% improvement in dysphagia score versus placebo (P=0.085). All adverse effects were grade 1, with no difference between groups.

This is the first study investigating ketamine’s efficacy in mucositis patients. Preliminary results support the low-dose, subcutaneous ketamine infusion as effective analgesia for moderate to severe mucositis pain.