CYP2D6 phenotype explains reported yohimbine concentrations in four severe acute intoxications.

The indole alkaloid yohimbine is an alpha-2 receptor antagonist used for its sympathomimetic effects. Several cases of yohimbine intoxication have been reported and the most recent one involved four individuals taking a yohimbine-containing drug powder. All individuals developed severe intoxication symptoms and were admitted to the hospital. Even though all individuals were assumed to have taken the same dose of the drug powder, toxicology analyses revealed yohimbine blood concentrations of 249-5631 ng/mL, amounting to a 22-fold difference. The reason for this high variability remained to be elucidated. We used recently reported knowledge on the metabolism of yohimbine together with state-of-the art nonlinear mixed-effects modelling and simulation and show that a patient's cytochrome P450 2D6 (CYP2D6) phenotype can explain the large differences observed in the measured concentration after intake of the same yohimbine dose. Our findings can be used both for the identification of safe doses in therapeutic use of yohimbine and for an explanation of individual cases of overdosing.

Severe acute intoxication with yohimbine: Four simultaneous poisoning cases.

Yohimbine is an indole alkaloid from the leaves and bark of the Pausinystalia johimbe tree that has acquired an enviable reputation in treating erectile dysfunction. This report presents four simultaneous severe poisoning/death cases caused by yohimbine. The test samples comprised the venous blood of four middle-aged men (aged 47-65) who were suspected of poisoning; one of the men died due to ineffective rescue. Ethanol concentration determination and toxicological routine screening were performed using gas chromatography with flame ionization detection (GC-FID) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). A specific LC-MS/MS method was developed to quantify yohimbine, which showed concentrations of 459, 249, and 301ng/mL in three poisoned blood samples and concentrations as high as 5631ng/mL in the deceased. Moreover, the deceased's autopsy ruled out death from trauma and previous illness, and no other common toxic components were detected in his blood. Therefore, yohimbine poisoning appears to be the most likely cause of death. As a type of alkaloid that can be employed in the treatment of clinical diseases and additives for supplements, the danger of yohimbine should be of widespread concern in society.

An Increase in Dietary Supplement Exposures Reported to US Poison Control Centers.

INTRODUCTION: The objective of this study was to investigate the epidemiology of dietary supplement exposures in the USA. METHODS: A retrospective analysis was conducted of out-of-hospital dietary supplement exposures reported to the National Poison Data System from 2000 through 2012. RESULTS: There were 274,998 dietary supplement exposures from 2000 through 2012. The annual rate of dietary supplement exposures per 100,000 population increased by 46.1% during 2000-2002, decreased 8.8% during 2002-2005, and then increased again by 49.3% from 2005 to 2012. These trends were influenced by the decrease in ma huang exposures starting in 2002. Miscellaneous dietary supplements accounted for 43.9% of all exposures, followed by botanicals (31.9%), hormonal products (15.1%), and other supplements (5.1%). The majority of dietary supplement exposures (70.0%) occurred among children younger than 6 years old and were acute (94.0%) and unintentional (82.9%). Serious medical outcomes accounted for 4.5% of exposures and most (95.0%) occurred among individuals 6 years and older. Ma huang products, yohimbe, and energy products were the categories associated with the greatest toxicity. CONCLUSIONS: There was an overall increase in the rate of dietary supplement exposures from 2000 through 2012. Although the majority of these exposures did not require treatment at a health care facility or result in serious medical outcomes, exposures to yohimbe and energy products were associated with considerable toxicity. Our results demonstrate the success of the FDA ban on ma huang products and the need for FDA regulation of yohimbe and energy products in the USA.

Adverse drug events associated with yohimbine-containing products: a retrospective review of the California Poison Control System reported cases.

BACKGROUND: Herbal supplements are classified as foods rather than drugs and are not required to undergo premarketing review by the Food and Drug Administration. Yohimbine is an alpha(2)-antagonist available in both prescription and herbal supplement products. OBJECTIVE: To determine the prevalence and severity of yohimbine-related adverse drug events (ADEs) reported to the California Poison Control System (CPCS). METHODS: A retrospective review of the CPCS electronic database of cases within a 7-year period (2000-2006) was conducted. Cases involving adults aged 18 and older who were symptomatic following exposure to a yohimbine-containing product, with a causality rating of possible or better on the Naranjo scale, were included. RESULTS: A total of 238 cases were identified. There was a substantial increase in the annual prevalence of yohimbine-associated ADEs reported to the CPCS between 2000 and 2006; specifically, the prevalence (per 10,000 total adult exposures) increased from 1.8 cases in 2000 to 8.0 cases in 2006). The majority (98.7%) of cases involved herbal (vs prescription) yohimbine products. Common reasons for use included sexual enhancement (27.7%), weight loss (9.2%), and stimulant effects (7.6%). Common ADEs reported included: gastrointestinal distress (46%), tachycardia (43%), anxiety/agitation (33%), and hypertension (25%). Yohimbine exposures were associated with a significantly greater proportion of severe outcomes and were more likely to require management at a health-care facility than the average substance exposure reported to the CPCS (odds ratios [95% CIs] were 5.81 [4.43 to 7.64] and 2.35 [1.82 to 3.04], respectively). CONCLUSIONS: A substantial increase in the prevalence of ADEs associated with yohimbine herbal products was seen between 2000 and 2006. These ADEs were associated with significantly more serious outcomes than the average exposures reported to the CPCS. A reexamination of whether yohimbine should be considered a "safe" dietary supplement under the Dietary Supplement Health and Education Act is warranted.

Acute neurotoxicity after yohimbine ingestion by a body builder.

Yohimbine is an alkaloid obtained from the Corynanthe yohimbe tree and other biological sources. Yohimbine is currently approved in the United States for erectile dysfunction and has undergone resurgence in street use as an aphrodisiac and mild hallucinogen. In recent years yohimbine use has become common in body-building communities for its presumed lipolytic and sympathomimetic effects. We describe a 37-year-old bodybuilder in which severe acute neurotoxic effects occurred in 2 h after yohimbine ingestion. The patient presented with malaise, vomiting, loss of consciousness, and repeated seizures after ingestion of 5 g of yohimbine during a body-building competition in a gymnasium. His Glasgow Coma Score was 3, requiring orotracheal intubation. Two hours after admission, vital signs were blood pressure 259/107 mmHg and heart rate 140 beats/min. Treatment with furosemide, labetalol, clonidine, and urapidil and gastrointestinal decontamination were performed. Twelve hours later the patient was extubated with normal hemodynamic parameters and neurological examination. The yohimbine blood levels at 3, 6, 14, and 22 h after ingestion were 5,240; 2,250; 1,530; and 865 ng/mL, respectively, with a mean half-life of 2 h. Few data are available about yohimbine toxicity and the related blood levels. This is a case of a large ingestion of yohimbine in which severe hemodynamic and neurological manifestations occurred and elevated blood levels of yohimbine were detected.

Yohimbine: a new street drug.

Following the ingestion of an alleged aphrodisiac known as "yo-yo," a 16-year-old girl experienced an acute dissociative reaction accompanied by weakness, paresthesias, and incoordination. Subsequent symptoms included anxiety, headache, nausea, palpitations, and chest pain. Hypertension, tachycardia, tachypnea, diaphoresis, pallor, tremors, and an erythematous rash were noted on physical examination. Serum epinephrine and norepinephrine levels were found to be elevated. Symptoms resolved spontaneously but lasted approximately 36 hours. The ingested substance was identified as yohimbine. The pharmacology of yohimbine and the treatment of yohimbine poisoning are discussed.