Over the counter drugs, Serotonin syndrome and failure of antiretroviral therapy

Q: 48 year old male is admitted to ICU with serotonin syndrome 3 weeks after he was started on Citalopram on an outpatient basis. Patient also has an history of HIV and on admission his viral load appears to be high. Family reported him to be very health conscious since his diagnosis of HIV few years ago, and fully compliant with his prescriptions. Also, he is taking many nutritional products to keep himself healthy. Which of the following over the counter drug is the most probable cause of his serotonin syndrome and failure of anti-retroviral therapy?

A) Coenzyme Q10 
B) Fish oil 
C) Ginkgo biloba 
D) Green tea 
E) St. John's wort 


Answer: E

Although any over the counter drug can downgrade or upgrade the effects of any prescription drug but St. John's wort, the common name for Hypericum perforatum, should be used with caution in patients with centrally acting medicines as they are very prone to cause serotonin syndrome. Also, it can cause failure of antiretroviral therapy in HIV patients. There is a component in St. John's wort called hyperforin which induces the cytochrome P450 3A4 (CYP3A4) system, which metabolizes many drugs including protease inhibitors, cyclosporine, oral contraceptives, warfarin, and digoxin. FDA has advisory against its use with HAART (antiretroviral regimen) medications. 3

Ginkgo biloba tends to do more coagulopathy. Other choices given above are relatively safe.

#pharmacology



References:

1. Wong AH, Smith M, Boon HS. Herbal remedies in psychiatric practice. Arch Gen Psychiatry 1998; 55:1033. 

2. Lantz MS, Buchalter E, Giambanco V. St. John's wort and antidepressant drug interactions in the elderly. J Geriatr Psychiatry Neurol 1999; 12:7.

3. Food & Drug Administration: Center for Drug Evaluation and Research. FDA Public Health Advisory - Risk of drug interactions with St John's wort and indinavir and other drugs. February 10, 2000. Last accessed on 1-27-2009.