{"id":2144,"date":"2021-11-01T12:00:11","date_gmt":"2021-11-01T12:00:11","guid":{"rendered":"http:\/\/moomango.co.uk\/guides\/?page_id=2144"},"modified":"2021-12-11T22:58:41","modified_gmt":"2021-12-11T22:58:41","slug":"side-effects-and-drug-levels","status":"publish","type":"page","link":"https:\/\/i-base.info\/guides\/side\/side-effects-and-drug-levels","title":{"rendered":"Side effects, drug levels and genetics"},"content":{"rendered":"<p><strong>Most drugs are approved at one standard dose even though different people absorb drugs differently. This can be related to differences in our genes and is a new area of research called pharmacogenetics.<\/strong><\/p>\n<p>For example, tiny differences in your DNA can explain the differences in levels of drugs including efavirenz, nevirapine and atazanavir.<\/p>\n<p><strong>Just as the blood levels of a drug affect how effective it is, they also affect the chance of side effects.<\/strong><\/p>\n<p>Drug levels for some HIV drugs can be checked using a test called therapeutic drug monitoring (TDM). The dose can then be changed if they are too high or too low.<\/p>\n<ul>\n<li>Protease inhibitors, NNRTIs and integrase inhibitors <b><i>can<\/i><\/b> be measured.<\/li>\n<li>Nukes (3TC, FTC, abacavir, tenofovir DF and TAF) <b><i>can not <\/i><\/b>be measured. This is because the important levels of these drugs are inside cells and the tests measure drug levels in blood.<\/li>\n<\/ul>\n<p>TDM is not routinely used but it is important in some situations.<\/p>\n<h2>When TDM might be considered<\/h2>\n<p><strong>TDM can be important when routine dosing is appropriate<\/strong>.<\/p>\n<p>For example:<\/p>\n<ul>\n<li>In children.<\/li>\n<li>In people with pre-existing liver or kidney damage.<\/li>\n<li>When drug levels might be linked to side effects. If you get yellow eyes with atazanavir TDM can help find an effective lower dose.<\/li>\n<li>When drug interactions are a concern. For example, when antacid drugs like omeprazole reduce levels of atazanavir and cause treatment to fail.<\/li>\n<\/ul>\n<p>TDM involves taking a blood sample, usually after you have been on a treatment for at least two weeks.<\/p>\n<p><strong>The hospital needs to know the exact time that you took your previous dose in order to interpret the results.<\/strong><\/p>\n<p>Sometimes a sample is taken just before you are due to take your next dose, and sometimes it is also taken 2\u20133 hours afterwards.<\/p>\n<p>TDM is part of an individualised approach for specific groups of people on ART.<\/p>\n<p><strong>More information on TDM<\/strong><\/p>\n<ul>\n<li><a href=\"http:\/\/www.lab21.com\/ClinicalLab\/Services\/HealthcareProfessionals\/DRUGMANAGEMENT\/HIVTherapeuticDrugMonitoring.aspx\">Lab 21<\/a> Commercial lab in the UK running TDM)<\/li>\n<\/ul>\n<p><strong>Drug interaction websites<\/strong><\/p>\n<ul>\n<li><a href=\"http:\/\/www.hiv-druginteractions.org\">HIV Drug Interactions &#8211; University of Liverpool<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Most drugs are approved at one standard dose even though different people absorb drugs differently. This can be related to differences in our genes and is a new area of research called pharmacogenetics. For example, tiny differences in your DNA &hellip;<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":291,"menu_order":8,"comment_status":"closed","ping_status":"closed","template":"page-guides.php","meta":{"footnotes":""},"class_list":["post-2144","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/2144","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/comments?post=2144"}],"version-history":[{"count":0,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/2144\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/291"}],"wp:attachment":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/media?parent=2144"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}