Archived posting to the Leica Users Group, 2006/05/24
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]On May 24, 2006, at 4:56 AM, Allen Graves wrote: > Chloroquine (used for treating malaria) and its cousin, Plaquenil > (hydroxychloroquine)-used for treating rheumatologic disorders like > lupus- can also cause color blindness. > > When I use ethambutol the normal screening for retinal toxicity is > to check color vision IF the drug is going to be used for more than > 2 or 3 months. It takes several months for toxicity to develop and > it is usually reversible if detected early. Screening is usually > every month or two after the first 3 months. If is continued too > long after toxicity develops it can cause macular degeneration. We > usually use ethambutol for 2 months and then discontinue it. > > The risk of toxicity from ethambutol is quite small compared to the > risk of dying from untreated drug-resistant tuberculosis. > > I've never used chloroquine for long enough to have to bother with > vision screening. Patients on Plaquenil are usually screened every > 6 months or so. > > As far as I know, the mechanism of ethamutol toxicity is direct > toxicity to the retinal receptor cells. The cones, which detect > color, seem to be more sensitive and develop problems earlier (if > problems are going to develop-I've only seen this once), allowing > color vision to be used as a screening tool. > > I am unable to find any problems with color blindness caused by > the sort of antibiotics used for sepsis. nice summary Allen, thank you. We check kids that are on ethambutol (which is rare) but I have never seen toxicity documented. As far as all the antibiotics used for bacterial infections/sepsis, not aware of any problems...Steve > > Allen > >> hi Greg, a fascinating question, yours... I will tell you what I >> have found so far, and I'll share it with the LUG list... >> >> ethambutol, a drug which is part of multidrug TB therapy, can >> sometimes affect vision and especially color vision. >> >> this seems to be generally what is referred to, when we google... >> >> (I am not sure what the mechanism is...) >> >> I am also checking to see if any of the customary antibiotics >> that are used to treat bacterial sepsis, may also cause >> risk...though of this I don't know, but I'm further searching the >> medical literature...and if I find something I'll let you know. >> >> It's a provocative question... one that I have never seen >> investigated in questions of antibiotic toxicity, with the >> exception of the drug ethambutol... >> the LUG sure can be an amazing source of information, >> >> Steve >> >> >> >> >> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information