Using 6% gabapentin, 4% amitriptyline, ketoprofen 10%, lidocaine 5%, and ketamine 10% probably in Lipoderm could give some relief topically. Ketamine 100 mg/ml with 0.1 ml spray nasally could give additional relief. 30% mannitol might be good here.
Case Rep Med. 2015;2015:392874. doi: 10.1155/2015/392874.
Topical and intranasal analgesic therapy in a woman with refractory postherpetic neuralgia.
Hohmeier KC(1), Almon LM
http://downloads.hindawi.com/journals/crim/2015/392874.pdf
- 20% of shingles cases may develop post herpetic neuralgia
- “as many as half of patients failing to respond to any treatment; other patients may experience limited efficacy despite being on multiple agents.”
- “oral medications often carry with them a high risk of adverse effects”
- “According to White et al., herpes zoster patients with PHN have a mean of 17.1 prescriptions filled compared to 5.5 prescriptions for patients without PHN”
- 78 yr old with PHN head and neck with actual sharp neuralgic component to problem.
- Neither 0ral Amitriptyline nor topical Capsaicin 0.025% were tolerated ( I would have added 5% lidocaine and 0.5% Hydrocortisone to Capsaicin to cut down pain and irritation of application). Capsaicin 0.075% had been shown to maybe reduce pain up to 23–30%; authors suggest pretreatment with topical lidocaine.
- Could not manage increases in oral gabapentin and oxcarbazepine ( In elderly I would stick to pregabalin but tolerance is still a problem and hence lack of effectiveness). Oxcarbazepine (trade name Trileptal) is better tolerated than carbamazepine (Tegretol) but still not well tolerated – and expensive as not covered by our drug plan. Usual Oxcarbazepine maintenance dose is 900 mg orally per day.
- 5% lidocaine patches were insufficient ( In Canada we don’t have patches so 5 – 10% lidocaine in Uremol lotion might have to do (the urea increases efficacy).
Topical treatment
- In case study, fiddled with formulation and came up with gabapentin 6%, ketoprofen 10%, lidocaine 5%, and ketamine 10%. Left out the amitriptyline because patient hated oral amitriptyline. 4% amitriptyline was found better than 2% in one poster presentation:
APS meeting Vancouver 2007 Poster #: 787
Title: A multicenter, double-blind, randomized, placebo controlled study of the efficacy/safety of two doses of amitriptyline/ketamine topical cream in treating post-herpetic neuralgia (PHN)
Authors: D Everton, D Bhagwat,M Damask
http://www.ampainsoc.org/db2/abstract/view?poster_id=3208#787
Problem with topicals is that they don’t come cheap…. - I tried using PLO gels on face and it causes irritation so I have found Lipoderm better.
- For mucosal irritation, 10% gabapentin “compounded with commercially available Orabase (a gel with benzocaine 20%)” was used in above study.
Ketamine
- Ketamine 100 mg/mL (10%) metered-dose intranasal spray delivering 0.1 mL/spray. “Patient was directed to inhale 1 spray (0.1 mL), alternating nostrils 90 seconds apart, up to three times daily (with a maximum of 5 sprays per dose) for breakthrough pain. The patient was asked to lie in a supine position with her neck extended at a 45-degree angle and to maintain this position for 30 seconds after administration.”…”The patient reported breakthrough pain relief on intranasal ketamine within 2–5 minutes after administration, on average 2–4 sprays (0.2–0.4 mLs) of the solution.”
- I’ve no experience with that and think this won’t come cheap.
- Authors suggest intranasal delivery of Ketamine could effect the trigeminal nerve directly and have more than systemic effect for facial neuralgias. Onset intranasal ketamine is 10 minutes , and it lasts 60 minutes apparently.
- Contacted a compounding pharmacy in town (Hill Ave. Pharmacy) and the only ketamine spray they make is 12.5 mg /ml – doesn’t seen as likely to help though one could start there and work up. They do have the powder though and could make up 100 mg/ml. Suspect would not be cheap and there is NO palliative care coverage for it.
Comment – I would like to beg the authors forgiveness for narrating his report but felt this information is desperately needed out there. Apparently there was a case or PHN told there was nothing that could be done for him and so he shot himself.. That is just tragic. I hope this blog note helps someone.
Just came back from the Canadian Pain Society Meeting in PEI. Helene Bertrand with UBC in Vancouver is making up a 30% mannitol in a vanishing cream that apparently can greatly help 55% of skin pain cases. I ordered some mannitol powder off ebay and can’t wait to try it. Helene is hoping to market it and has fine tuned the cream. She makes the point that some cases are so tender, they cannot rub in a cream – for those put cream on saran wrap and just place the wrap on the skin.