Potential liver toxicity of herbal supplement NMDA relief Exendo
The Netherlands Pharmacovigilance Centre Lareb received two reports of liver toxicity associated with the use of herbal supplement NMDA relief Exendo. One patient needed a liver transplantation as a result of the liver damage. The other patient recovered from the hepatitis after discontinuation of NMDA relief Exendo.
NMDA relief Exendo is a herbal supplement. It is used to increase concentration and focus as it promotes relaxation and reduces anxiety for persons experiencing mental pressure. The product has no registration as a medicine in the Netherlands. It is sold as a herbal supplement in drug stores and web shops.
NMDA relief Exendo contains among others the herb skullcap (Scutelaria lateriflora). For herbal supplements, not all herbs or synthetic compounds are always declared on the label describing the content of the supplement. For this reason in is sometimes difficult to indicate the exact toxic substance in a herbal supplement. Skullcap has however previously been associated with liver toxicity.
The remaining tablets from both patients were investigated. In the samples only the active substances from the skullcap were found, indicating that the liver toxicity would be caused by this active substance. There was a remarkable difference in the amount of skullcap between the sample tablets. Herbal supplements have less strict requirements concerning dose and quality compared to registered drugs.