Naming the problem
Four months after shingles on the left chest, the rash has healed, but the client has burning, shooting pain along the same band and finds even the touch of her blouse painful. Pain from a stimulus that is normally not painful is allodynia. Pain that persists along a dermatome after the zoster rash heals is postherpetic neuralgia, a form of neuropathic pain caused by damage to the sensory nerve during the infection. Neuropathic pain responds to drugs that calm overactive nerve signaling, not to standard anti-inflammatory analgesics.
First-line drug classes and why gabapentin fits her
First-line drugs for neuropathic pain are the gabapentinoids (gabapentin, pregabalin), the tricyclic antidepressants (such as amitriptyline), and the serotonin–norepinephrine reuptake inhibitors. Topical lidocaine is also used for localized pain. Choosing among them depends on the client's other conditions. This client had a myocardial infarction two months ago, and tricyclics are avoided after a recent myocardial infarction because of their effects on cardiac conduction. Her kidney function is normal, so gabapentin can be given at a usual starting dose. A low bedtime dose such as 300 mg lets her adjust to its drowsiness and dizziness before the dose is increased.
| Option | Fit for her? | Reason |
|---|
| Gabapentin | Best | First-line; no cardiac conduction concern; kidneys normal |
| Amitriptyline | Avoid | Tricyclic; conduction effects after recent MI |
| Ibuprofen | Poor | NSAIDs largely ineffective for neuropathic pain; add cardiovascular risk |
| Acyclovir | No | Helps only in acute zoster, not months later |
Why the distractors are wrong
Amitriptyline is a reasonable drug for neuropathic pain in general, which is what makes it tempting, but her recent infarction rules it out. Ibuprofen and other NSAIDs relieve inflammatory pain but do little for neuropathic pain, and they add cardiovascular and kidney risk in a client with recent heart disease. Acyclovir treats active varicella-zoster replication and is started early in acute shingles; months after the rash has healed there is no active infection to treat, and it does not relieve postherpetic pain.
Nursing considerations with gabapentin
The nurse teaches that gabapentin can cause drowsiness, dizziness, and unsteadiness, so she should rise slowly and take fall precautions, especially as an older adult. The drug is not stopped suddenly, and relief builds over days to weeks as the dose is adjusted. Gabapentin is cleared by the kidneys, so doses are reduced if kidney function declines. Nonpharmacologic measures such as loose, soft clothing over the area also help with allodynia.
Exam takeaway
Key point For neuropathic pain, choose a first-line agent that is safe for the client's other conditions. After a recent myocardial infarction, a gabapentinoid is preferred over a tricyclic.