Side effects of pharmaceuticals not elicited by comparable herbal medicines: The case of tetrahydrocannabinol and marijuana

Objective Herbalists claim that the polypharmacy of botanical remedies prov ides 2 advantages over single-ingredient drugs: (1) primary active ingredie nts in herbs are synergized by secondary compounds, and (2) secondary compo unds mitigate the side effects caused by primary active ingredients. To exa mine this second claim, medical marijuana was compared with its primary act ive ingredient, tetrahydrocannabinol. Data Sources A search on MEDLINE (1966-1999), AGRICOLA (1990-1999), and Bio logical and Agricultural Index (1964-1999) using keywords "cannabinoids," " marijuana, " "tetrahydrocannabinol," "Cannabis," and "hemp." Phytochemical and ethnobotanical data sere searched with the Agricultural Research Servic e database. Unindexed botanical journals were scanned by hand. Study Selection Studies documenting the efficacy of secondary compounds mit igating sine effects of tetrahydrocannabinol consisting of double-blind tri als, unblinded studies, animal models, and in vitro experiments. Data Extraction and Data Synthesis Data validity was assessed by consensus, weighted by source (peer-reviewed article vs popular press), identificatio n methodology (analytical chemistry vs clinical history), and frequency of independence observations. Conclusions Good evidence suggests that some side effects of tetrahydrocann abinol an mitigated by other volatile compounds present in the essential oi l of marijuana. Inhaling tetrahydrocannabinol, which avoids first-pass hepa tic metabolism has advantages over ingesting if. Other cannabinoids, terpen oids, and flavonoids can reduce tetrahydrocannabinol-induced anxiety, choli nergic deficits, and immunosuppression. Other compounds increase cerebral b lood flour enhance cortical activity kill respiratory pathogens, and provid e anti-inflammatory activity. The ha;ards of marijuana smoke can be reduced with appropriate technology. Proprietary Cannabis extracts containing a mi xture of cannabinoids, terpenoids, and flavonoids are currently being devel oped and reared.