Page 199 Guide to Pain Management in Low-Resource Settings

Management of Postherpetic Neuralgia 187

procedures, when no general anesthesia is possible or sodium-channel-blocking anticonvulsant such as carba-
necessary. Th ese epidural catheters may be inserted at mazepine, which often is more successful in this specifi c
almost all levels (cervical, thoracic, or lumbosacral). If type of neuropathic pain.
the head or upper neck region is aff ected, then epidu-
ral analgesia will not succeed. Th ere is no evidence that If the standard drugs are not reducing the
regional anesthesia shortens the course of acute zoster pain adequately or cannot be tolerated due to
lasting side eff ects, what options are available,
or reduces the chances for PHN. Th erefore, such an in-
especially with allodynia?
vasive treatment would only be justifi ed with refractory
excruciating pain, in order to control pain for a limited When standard drugs do not reduce the pain adequate-
time period until the spontaneous reduction of pain oc- ly, especially with allodynia (pain in response to light
curs. touch in the aff ected dermatome), local topical therapy
Regional sympathetic chain blocks, for exam- options should be tried. A very good option would be
ple at the stellate ganglion or at the thoracic or lumbar topical local anesthetics, such as EMLA cream (which
sympathetic chain, are usually only possible as one-time might be available from the anesthesia department),
injections, and therefore do not control pain for more which can be very eff ective if used 3–4 times a day.
than a couple of hours. Th ese techniques have their use Lidocaine patches are small, bandage-like
in PHN at a specialized pain clinic when there is evi- patches that contain the topical pain-relieving medica-
dence that the pain is sympathetically maintained. tion, lidocaine. Th e patches, available by prescription,
must be applied directly to painful skin to deliver relief
What to do when the acute herpes zoster has for up to 12 hours (preferably at night). Patches contain-
healed and postherpetic neuralgia persists with ing lidocaine can also be used on the face, taking care to
intolerable pain? avoid mucus membranes including the eyes, nose, and
Clinical experience shows that successful treatment mouth. Th e advantage of EMLA cream and lidocaine
of established PHN is diffi cult. Th e main reason is the patches is that the local anesthetic they contain is only
considerable nerve damage present and the unlikeli- absorbed into the bloodstream in very low quantities,
hood that repair mechanisms will restore the nerve therefore avoiding any systemic side eff ects, but possibly
roots. Th erefore, the patient must be instructed not to causing local skin irritation.
have expectations that are too high. Th e goal of therapy EMLA cream and lidocaine patches are expen-
is, therefore not “healing” with complete recovery of the sive and are not yet available in most of the develop-
sensory defi cit and complete disappearance of pain, but ing countries. A cheap and available alternative is the
only the reduction of pain, and usually 50% reduction is local use of 5% lidocaine jelly. A thin fi lm, spread over
seen as a “successful treatment.” the painful area of skin and covered with a fi ne sheet of
polyethylene for 1 hour, eff ective in most patients. It is
What drugs should be chosen for postherpetic important to remove any jelly from the patient’s clothes.
neuralgia?
In general, the drugs of fi rst choice for PHN are the What other options would I have, where I
same as for treatment of pain in acute herpes zoster. have the possibility of referring the patient
Th erefore, the fi rst thing to do is to increase the dose of to a colleague experienced in invasive pain
the tricyclic antidepressant (e.g., amitriptyline 25 mg at procedures?
night) or the anticonvulsant (e.g., gabapentin 100 mg at Patients with pain unresponsive to systemic drug
night) or the weak opioid (e.g., tramadol) in a stepwise treatment could receive repeated nerve blocks of the
fashion, trying to reach the goal of 50% pain reduction. corresponding areas of pain, such as the intercostal
If this is not possible due to side eff ects, the tricyclic nerves. Apart from targeting the peripheral nerves,
antidepressant or the anticonvulsant should be com- the epidural or intrathecal space may be used to ap-
bined with a weak opioid. Th e next step would be to try ply analgesics. Epidural catheters, using, for example,
a strong opioid, such as morphine, to replace tramadol, 5 mL bupivacaine 0.125%, morphine 2 mg, and cloni-
titrating the morphine until pain reduction is achieved. dine 35 μg/12 hours, are eff ective for control of pain.
If attacks of pain, such as shooting or electrical pain, oc- Unfortunately, this catheter technique is not able to re-
cur, gabapentin or pregabalin should be replaced by a duce pain in the long term. Th erefore, after cessation