{"id":7312,"date":"2005-06-15T17:52:11","date_gmt":"2005-06-15T16:52:11","guid":{"rendered":"http:\/\/moomango.co.uk\/htb\/?p=7312"},"modified":"2014-05-21T17:40:16","modified_gmt":"2014-05-21T17:40:16","slug":"levels-of-efavirenz-10-fold-above-minimum-target-level-despite-coadministration-with-rifampicin","status":"publish","type":"post","link":"https:\/\/i-base.info\/htb\/7312","title":{"rendered":"Levels of efavirenz 10-fold above minimum target level despite coadministration with rifampicin"},"content":{"rendered":"

Simon Collins, HIV i-Base<\/strong><\/p>\n

Several studies have previously reported extremely high levels of efavirenz in African women, and this has been linked with discontinuation related to CNS side effects.<\/strong><\/p>\n

A case report from Liverpool University, detailed the response of a 40 year old Zambian women, diagnosed in June 2004 with a CD4 count of 34 cells\/mm3, who was started on AZT\/3TC\/efavirenz. [1] Five-drug rifampicin-based treatment for pulmonary TB was started 2 months later, and the dose of efavirenz was increased to 800mg daily.<\/p>\n

Drug level monitoring (TDM) two weeks after initiation of TB treatment, showed EFV trough levels around 27,500 ng\/ml (minimum effective target =1,000 ng\/mL; maximum target = 4,000 ng\/mL). Although no neurological side effects were reported, EFV dose was reduced to 600mg\/day. Drug levels two weeks later had increased to almost 44,500 ng\/mL and efavirenz was stopped. At this point she appeared vague, confused and was unsteady on her feet, while MRI brain scan was normal.<\/p>\n

The authors commented that EFV levels were still at toxic levels two weeks after discontinuation of treatment, and that TDM had been vital to enable correct management.<\/p>\n

A second poster at the meeting presented results from a retrospective survey of the Liverpool TDM database of patients from 1999-2004 who had used efavirenz at a dose of either 600mg (n=20) or 800mg (n=125) while taking rifampicin. [2]<\/p>\n

They reported a large interpatient variability in drug levels that resulted in no statistically different percentages of patients below the minimum target level, or above the maximum target level.<\/p>\n

References:<\/p>\n

    \n
  1. Crowe G, Khoo SH. Toxic levels of efavirenz (EFV) two weeks after stopping therapy. 11th Annual BHIVA Conference, 20-23 April 2005, Dublin. Poster P61.<\/li>\n
  2. Gibbons S, Almond L, Back D et al. Efavirenz concentrations resulting from co-administration of rifampicin with either 600 or 800mg efavirenz. 11th Annual BHIVA Conference, 20-23 April 2005, Dublin. Poster P33.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

    Simon Collins, HIV i-Base Several studies have previously reported extremely high levels of efavirenz in African women, and this has been linked with discontinuation related to CNS side effects. A case report from Liverpool University, detailed the response of a …<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,34,8],"tags":[48],"class_list":["post-7312","post","type-post","status-publish","format-standard","hentry","category-conference-reports","category-pk-and-drug-interactions","category-side-effects","tag-bhiva-bashh-1st-2005"],"_links":{"self":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts\/7312","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/comments?post=7312"}],"version-history":[{"count":0,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts\/7312\/revisions"}],"wp:attachment":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/media?parent=7312"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/categories?post=7312"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/tags?post=7312"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}