Additionally, of every sixteen people treated with a TCA, one person is expected to stop the medication due to a bothersome side effect, such as dry mouth, constipation, or urinary retention (number needed to harm=16). The anticonvulsant medications pregabalin and gabapentin also effectively relieve postherpetic neuralgia pain. Treatment with pregabalin leads to a reduction in pain intensity of 50% or more in one person out of every 4–5 people treated (NNT=4–5). Similarly, treatment with gabapentin also leads to a 50% reduction in pain intensity in one person out of every 7-8 people treated (NNT=7.5).Opioids such as tramadol, methadone, oxycodone, and morphine have not been well-studied for postherpetic neuralgia treatment. Acetaminophen and nonsteroidal anti-inflammatory drugs are thought to be ineffective and have not undergone rigorous study for PHN. Prognosis
The natural history of postherpetic neuralgia involves slow resolution of the pain syndrome. A subgroup of affected individuals may develop severe, long-lasting pain that does not respond to medical therapy. Epidemiology
In the United States each year approximately 1,000,000 individuals develop herpes zoster. Of those individuals, approximately 10–18% develop postherpetic neuralgia.Fewer than 10 percent of people younger than 60 develop postherpetic neuralgia after a bout of herpes zoster, while about 40 percent of people older than 60 do. References
Further reading
Hempenstall K, Nurmikko TJ, Johnson RW, AHern RP, Rice AS (July 2005). "Analgesic therapy in postherpetic neuralgia: a quantitative systematic review". PLOS Medicine. 2 (7): e164. doi:10.1371/journal.pmed.0020164. PMC 1181872. PMID 16013891. == External links ==
Use caution with a history of GI disease (bleeding or ulcers), concurrent therapy with aspirin, anticoagulants and/or corticosteroids, smoking, use of alcohol, the elderly or debilitated patients. Use the lowest effective dose for the shortest duration of time, consistent with individual patient goals, to reduce risk of GI adverse events; alternate therapies should be considered for patients at high risk. When used concomitantly with ≤325 mg of aspirin, a substantial increase in the risk of gastrointestinal complications (e.g., ulcer) occurs; concomitant gastroprotective therapy (e.g., proton pump inhibitors) is recommended. The increased risk is about 81%. Hematologic effects: Anemia may occur; monitor hemoglobin or hematocrit in people on long-term treatment. Celecoxib does not usually affect prothrombin time, partial thromboplastin time or platelet counts; it does not inhibit platelet aggregation at approved doses.People with prior history of ulcer disease or GI bleeding require special precaution. Moderate to severe liver impairment or GI toxicity can occur with or without warning symptoms in people treated with NSAIDs. In October 2020, the U.S. Food and Drug Administration (FDA) required the drug label to be updated for all nonsteroidal anti-inflammatory medications to describe the risk of kidney problems in unborn babies that result in low amniotic fluid. They recommend avoiding NSAIDs in pregnant women at 20 weeks or later in pregnancy. Allergy
Celecoxib contains a sulfonamide moiety and may cause allergic reactions in those allergic to other sulfonamide-containing drugs. This is in addition to the contraindication in people with severe allergies to other NSAIDs.