Friday, November 3, 2006
Natural history of PHN; truth telling and cancer; a few more scraps of data on methadone; spirituality & HIV
Several things in brief before the weekend:
Pain has a prospective study looking at the natural history of post-herpetic neuralgia. It followed 94 older patients who had shingles and were felt to be at high risk for PHN (defined as having acute pain over 2/10 for at least 48 hours). 30 patients had PHN at 6 months (defined as any residual pain); however only 2 patients had pain at least 3/10 at 6 months. A substantial number of patients had pain for much of the study period (although most had resolved by 6 months). An interesting finding of this study was a suggestion that pain decreased at the same rate for the subjects: the worse your pain was at baseline the longer it would take for your pain to go away, but it overall steadily decreased. Overall this study adds to the perception that PHN that is both severe and prolonged is rare.
Lancet Oncology has a "personal view" piece about truth telling in oncology . It's pretty good.
For you methadone junkies out there (poor choice of words I guess...):
Therapeutic Drug Monitoring has a study on methadone enantiomers in hospice patients. This is a small study of 13 hospice cancer patients who were switched to methadone from morphine. I am sure there are many elements to this study which will be of interest to the more pharmacologically minded, but I took note of it because there still remains such little data on switching to methadone that everything published is of interest. (The study hails from my familial homeland of beautiful Perth, Australia.) Overall the study lends support to the consensus on methadone: a) final morphine:methadone "equianalgesic" ratios varied widely (final mean ratio was 5.2:1, range 1.3-11) between patients; b) methadone's potency generally increased as baseline morphine dose increased; and c) methadone's half-life is very long (averaged in the 30-50 hour range). For what it's worth, about half the patients achieved "optimal pain control" with the switch but I can't say the study is a resounding endorsement of rotation to methadone. Analgesia seemed to have little relation to methadone serum level. One patient had super-high methadone serum levels but this was not apparently clinically evident. Despite these two findings the authors for some reason recommend following methadone levels in hospice patients, but their study seems to support the futility of doing this as far as I can tell.
The Journal of General Internal Medicine has an entire supplement issue on spirituality and HIV/AIDS patients .