Lidocaine intranasal spray for treatment of trigeminal neuralgia
Cambridge, UK
E-mail: dww21{at}cam.ac.uk
Editor—Kanai and colleagues1 are to be congratulated on their study of the efficacy of lidocaine 8% intranasal spray for the treatment of paroxysmal second division trigeminal neuralgia. They showed that 0.2 ml of lidocaine 8% applied to the sphenopalatine ganglion, which lies just posterior to the middle turbinate, provides effective pain relief for approximately 4 h. They observed that 15 out of 25 subjects felt burning or stinging in the treated nostril and commented that this made the study difficult to blind.
Lee and colleagues2 recently described a means of inserting a laryngeal mask airway using topical anaesthesia with lidocaine 10% combined with a remifentanil infusion. All the subjects experienced a sore throat afterwards. I experienced a very sore throat after topical anaesthesia with lidocaine 10% when participating in a fibre-optic intubation course. A fibre-optic intubation instructor I know believes the incidence of burning and stinging increases proportionately with lidocaine concentration and avoids very concentrated lidocaine solutions for this reason despite the lack of published data on the matter.
I appreciate that lidocaine 8% was chosen for this study to reduce the volume administered, as participants in other studies have reported an unpleasant taste and swallowing difficulties as a result of local anaesthetic applied to the nostril reaching the pharynx and larynx.3 4 However, it would have been useful if Kanai and colleagues had communicated the proportion of patients continuing to use the lidocaine 8% spray after the study ended, providing a good indication to the tolerability of the treatment and reassurance that it does not simply replace one pain with another.
Kitasato, Japan
E-mail: kanaiakifumi{at}aol.com
We greatly appreciate the comments by Dr Wheeler regarding our article on intranasal lidocaine 8% spray. As he described, 0.2 ml of lidocaine 8% frequently produces burning, stinging, or numbness of the treated nostril, resulting in unpleasantness for patients. In our department, the treatment is not the first-line therapy for trigeminal neuralgia. However, we often apply intranasal lidocaine spray to patients with refractory trigeminal neuralgia. Most patients prefer the intranasal spray to trigeminal nerve block with a needle because of prompt analgesia without severe pain attendant on procedure. Further work is required to assess the proper concentration and volume of intranasal lidocaine in order to provide a better effect and at the same time less unfavourable adverse effects in patients with refractory trigeminal neuralgia.
References
1 Kanai A, Suzuki A, Kobayashi M, Hoka S. (2006) Intranasal lidocaine 8% spray for second-division trigeminal neuralgia. Br J Anaesth 97:559–63.
2 Lee MC, Absalom AR, Menon DK, Smith HL. (2006) Awake insertion of the laryngeal mask airway using topical lidocaine and intravenous remifentanil. Anaesthesia 61:32–5.[CrossRef][Web of Science][Medline]
3 Sadek SA, De R, Scott A, White AP, Wilson PS, Carlin WV. (2001) The efficacy of topical anaesthesia in flexible nasendoscopy: a double-blind randomised controlled trial. Clin Otolaryngol Allied Sci 26:25–8.
4 Kudrow L, Kudrow DB, Sandweiss JH. (1995) Rapid and sustained relief of migraine attacks with intranasal lidocaine: preliminary findings. Headache 35:79–82.[CrossRef][Web of Science][Medline]
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