From the Guidelines
Patients taking Strattera (atomoxetine) should have baseline labs before starting treatment and annual monitoring thereafter, including liver function tests, cardiovascular assessment, weight, and height in children, to minimize the risk of adverse effects and monitor for potential changes in morbidity, mortality, and quality of life 1. When initiating Strattera, it is essential to perform a complete blood count, liver function tests, and cardiovascular assessment, including blood pressure and heart rate, to establish a baseline for future monitoring 1.
Annual Monitoring
Annual monitoring should include:
- Liver function tests (ALT, AST) to assess for potential liver damage, as Strattera is metabolized primarily through the CYP2D6 enzyme pathway in the liver 1
- Blood pressure and heart rate to monitor for potential cardiovascular effects, as Strattera can increase blood pressure and heart rate 1
- Weight and height in children to monitor for potential growth delays, as Strattera has been linked to growth delays compared to expected trajectories in the first 1 to 2 years of treatment 1
Additional Considerations
Some patients may be poor metabolizers of CYP2D6, leading to higher blood levels of the medication and potentially more side effects, emphasizing the importance of monitoring and potential dose adjustment 1. Additional monitoring may be needed for patients with pre-existing liver or cardiovascular conditions, and clinicians should be aware of the potential for increased suicidal thoughts, gastrointestinal symptoms, and other adverse effects associated with Strattera 1. By prioritizing regular monitoring and baseline assessments, clinicians can minimize the risk of adverse effects and optimize treatment outcomes for patients taking Strattera, ultimately improving morbidity, mortality, and quality of life.
From the FDA Drug Label
Atomoxetine is eliminated primarily by oxidative metabolism through the cytochrome P450 2D6 (CYP2D6) enzymatic pathway and subsequent glucuronidation. Laboratory tests are available to identify CYP2D6 PMs Routine laboratory tests are not required. CYP2D6 metabolism - Poor metabolizers (PMs) of CYP2D6 have a 10-fold higher AUC and a 5-fold higher peak concentration to a given dose of atomoxetine hydrochloride compared with extensive metabolizers (EMs).
Straterra Metabolism and Yearly Labs:
- Atomoxetine is metabolized through the CYP2D6 pathway.
- Yearly labs are not required for patients taking atomoxetine, but laboratory tests are available to identify CYP2D6 poor metabolizers (PMs) 2.
- Patients who are CYP2D6 PMs may require dosage adjustment of atomoxetine hydrochloride 2.
From the Research
Straterra Metabolism
- Straterra, also known as atomoxetine, is primarily eliminated via cytochrome P4502D6 (CYP2D6) 3
- The pharmacokinetics of atomoxetine and its primary metabolites were investigated in adults with hepatic impairment, and the results showed that the systemic clearance of atomoxetine was significantly reduced in those with hepatic impairment compared with controls 3
Yearly Labs for Straterra
- Monitoring of liver function tests is crucial for patients taking atomoxetine, as it can cause hepatotoxicity 4, 5
- The predictive value of liver "function" tests for monitoring hepatotoxicity is limited, and alternative methods may be needed 6
- Patients with jaundice or laboratory evidence of liver injury should discontinue atomoxetine and not restart it 5
Hepatotoxicity Associated with Straterra
- Atomoxetine has been associated with reversible liver injury, and three spontaneously reported cases of reversible drug-induced liver injury were deemed probably related to it 5
- The risk of hepatotoxicity associated with atomoxetine is rare, but monitoring of liver function tests is still necessary 4, 5
- Other medications, such as antidepressants, can also cause hepatotoxicity, and monitoring of liver function tests is essential for patients taking these medications 4