Efficacy of IV magnesium on neuropathic pain - BJA 2002

From the BJA - here.

Results. During the administration, pain scores were significantly lower for magnesium compared with placebo at 20 and 30 min (P=0.016) but not at 10 min. I.V. magnesium sulphate was safe, well-tolerated and effective in patients with postherpetic neuralgia.
Conclusion. The present study supports the concept that the N-methyl-D-aspartate receptor is involved in the control of postherpetic neuralgia. 

QUESTIONS ARISING
1. What effect does Mg have on neuropathic pain after this period?
2. What effect would Mg have on chronic/acute pain?
3. Would this change your practice in management of PHN pain?
4. Would you consider Mg as part of your NMDA receptor blockade regime?
5. Does this have implications for other areas of practice with people and chronic pain?
6. Was the study large enough to boast the effects stated? This was a small, double-blind, placebo-controlled, cross-over study.