Application to Butterbur Products of a Suggested Daily Intake-Based Safety Evaluation of Individual Herbal Supplements with Cytochrome P450 Expression as a Major Index

The present paper first proposes a method for ensuring the safety of commercial herbal supplements, termed the suggested daily intake-based safety evaluation (SDI-based safety evaluation). This new method was inspired as a backward analog of the acceptable daily intake (ADI) derivation from the no observed adverse effect level (NOAEL), the basis of food additive risk analysis; namely, rats are dosed with individual herbal supplement products at the SDI for human use multiplied by 100 (the usual uncertainty factor value) per body weight for 8 d. The primary endpoint is the sign of adverse effects on liver, especially gene expression of cytochrome P450 (CYP) isoforms. The proposed method was then applied to three butterbur (Petasites hybridus) products without pyrrolizidine alkaloids but lacking clear safety information. Results showed that two oily products markedly enhanced the mRNA expression of CYP2B (>10-fold) and moderately enhanced that of CYP3A1 (<4-fold) with liver enlargement. These products also caused the renal accumulation of alpha 2-microglobulin. One powdery product showed no significant effect on liver and kidney. The large difference in effects of products was due to the difference in chemical composition revealed by liquid chromatography-mass spectroscopy. The oily and the powdery products required attention in terms of safety and effectiveness, respectively. Finally, the results from the SDI-based safety evaluation of butterbur and other herbal supplement products were grouped into four categories and cautionary notes were discussed. The SDI-based safety evaluation of their products by herbal supplement operators would contribute to safe and secure use by consumers.

New Approaches to Shifting the Migraine Treatment Paradigm

The standard of care paradigm for migraine treatment has been based almost exclusively on approaches that grew out of the happenstance use of market pharmaceuticals. Only methysergide, which has long since been removed from use for safety concerns, the ergotamine family of drugs, and the triptans were explicitly developed with migraine and other vascular headaches in mind. While the forward and innovative thinking to utilize the broad array of agents to treat migraine served millions well, their therapeutic efficacy was often low, and adverse event profiles were troublesome in the least. Advances in biochemical and molecular biology and the application of advanced "designing drugs" methods have brought about a potentially significant shift in treatment. The gepants have efficacies similar to the triptans but without vascular safety or medication overuse concerns. Preventative gepants offer innovative approaches to prevention and efficacy that exceed even the CGRP monoclonal antibodies. Those monoclonal antibodies brought rapid and highly effective outcomes across the spectrum of migraine. They outpaced older oral medication efficacy and eliminated most adverse events while potentially improving compliance with monthly or quarterly dosing. Other serotonin receptors beyond the 5HT1B and1D receptors have been targeted for decades. They now lead us to better formulations of dihydroergotamine for efficacy, convenience, and tolerability, and a 5HT1F-specific acute treatment like the gepants opens new options for acute management. Neuromodulation goes back to the mid-1800's. Our improved understanding of applied biomedical engineering has brought forward several tantalizing devices, including the application of currents distant from the target and patient regulated. Whether these advances change the paradigm of migraine treatment and standards of care remains to be seen, and issues such as cost and patient acceptance will help mold it.

Petasites for Migraine Prevention: New Data on Mode of Action, Pharmacology and Safety. A Narrative Review

Petasins are the pharmacologically active ingredients of butterbur and of therapeutic benefit in the treatment of migraine and tension headaches. Here, we summarize the pharmacology, safety and clinical efficacy of butterbur in the prevention of migraine attacks and present new data on its mode of action. We review published literature and study reports on the safety and clinical efficacy of the butterbur root extract Petadolex® and report new findings on petasins in dampening nociception by desensitizing calcium-conducting TRP ion channels of primary sensory neurons. Importantly, butterbur diminishes the production of inflammatory mediators by inhibiting activities of cyclooxygenases, lipoxygenases and phospholipase A2 and desensitizes nociception by acting on TRPA1 and TRPPV1 ion channels. It inhibits the release of calcitonin-gene related peptide (CGRP) of meningeal afferents during migraine attacks. We also evaluated the safety of a butterbur root extract in repeated dose studies for up to 6 months. A no-observable-adverse-effect-level at 15-fold of the maximal clinical dose (3 mg/kg/day MCD) was established for rats. At supratherapeutic doses, i.e., 45–90-fold MCD, we observed bile duct hyperplasia, and mechanistic studies revealed regulations of solute carriers to likely account for bile duct proliferations. Additionally, liver function tests were performed in cultures of primary human hepatocytes and did not evidence hepatotoxicity at therapeutic butterbur level and with migraine co-medications. Lastly, in randomized, double-blinded and placebo-controlled trials with Petadolex® migraine attack frequency was reduced significantly at 150 mg/day, and no relevant abnormal liver function was reported. Together, butterbur is effective in the prevention of migraine attacks by blocking CGRP signaling.

Migraine History and Outcomes in Military Pilots and Flight Surgeons

BACKGROUND: Migraine is a common disorder with significant aeromedical implications. The variability and unpredictable nature of occurrences hampers accurate assessment of future risk. This uncertainty results in a necessarily conservative approach to aeromedical recommendations, which unfortunately may lead to over-restrictive dispositions. Limited long-term follow up information is available on migraine outcomes in pilots, particularly assessing for impact of potential modifiable aggravating factors.Methods: This retrospective study reviewed 159 U.S. Air Force pilots with migraine who had been granted aeromedical waivers. As a comparison group, 44 U.S. Air Force flight surgeons with migraine who had been granted aeromedical waivers were reviewed.Results: Migraine with aura and isolated migraine aura without headache accounted for the majority of migraine subtypes in both male and female subjects. Self-identified triggering factors were identified by 62% of subjects. The most commonly reported triggers were dietary factors, sleep disturbances, stress, caffeine intake, and hormonal factors. Sleep disturbances, stress, hormonal factors, and ethanol triggers were more frequently noted in female subjects. Self-reported positive response to trigger factor modification was noted in 54% of subjects. Subjects reported an average of only 3 migraine attacks in the previous year. Long-term follow up indicated continued aeromedical waiver in 91% of subjects.Discussion: The majority of subjects had migraine with aura or isolated migraine aura. Significant salutary response to modification of commonly-reported triggering factors was noted. These findings can be incorporated into individualized aeromedically-compatible management strategies to clarify symptom impact on aviation safety, improve symptom control, and increase the possibility of safe return to fly recommendations.Hesselbrock RR, Haynes JT. Migraine history and outcomes in military pilots and flight surgeons. Aerosp Med Hum Perform. 2022; 93(1):26-31.

Metabolic Toxification of 1,2-Unsaturated Pyrrolizidine Alkaloids Causes Human Hepatic Sinusoidal Obstruction Syndrome: The Update

Saturated and unsaturated pyrrolizidine alkaloids (PAs) are present in more than 6000 plant species growing in countries all over the world. They have a typical heterocyclic structure in common, but differ in their potential toxicity, depending on the presence or absence of a double bond between C1 and C2. Fortunately, most plants contain saturated PAs without this double bond and are therefore not toxic for consumption by humans or animals. In a minority of plants, however, PAs with this double bond between C1 and C2 exhibit strong hepatotoxic, genotoxic, cytotoxic, neurotoxic, and tumorigenic potentials. If consumed in error and in large emouns, plants with 1,2-unsaturated PAs induce metabolic breaking-off of the double bonds of the unsaturated PAs, generating PA radicals that may trigger severe liver injury through a process involving microsomal P450 (CYP), with preference of its isoforms CYP 2A6, CYP 3A4, and CYP 3A5. This toxifying CYP-dependent conversion occurs primarily in the endoplasmic reticulum of the hepatocytes equivalent to the microsomal fraction. Toxified PAs injure the protein membranes of hepatocytes, and after passing their plasma membranes, more so the liver sinusoidal endothelial cells (LSECs), leading to life-threatening hepatic sinusoidal obstruction syndrome (HSOS). This injury is easily diagnosed by blood pyrrolizidine protein adducts, which are perfect diagnostic biomarkers, supporting causality evaluation using the updated RUCAM (Roussel Uclaf Causality Assessment Method). HSOS is clinically characterized by weight gain due to fluid accumulation (ascites, pleural effusion, and edema), and may lead to acute liver failure, liver transplantation, or death. In conclusion, plant-derived PAs with a double bond between C1 and C2 are potentially hepatotoxic after metabolic removal of the double bond, and may cause PA-HSOS with a potential lethal outcome, even if PA consumption is stopped.

Butterbur (Petasites hybridus) Extract Ameliorates Hepatic Damage Induced by Ovalbumin in Mice

The liver is the most vital organ that could be influenced by inducers of hypersensitivity such as ovalbumin. The current study was carried out to explore the effects of butterbur (Petasites hybridus) extract on the ovalbumin-induced liver hypersensitivity in Swiss albino male mice. Animals were divided into 4 groups, 1^st group served as a control group, 2^nd group treated with daily oral administration of 75 mg/kg of butterbur extract, 3^rd group received single oral dose 100 mg/kg of ovalbumin to induce hypersensitivity, and 4^th group treated with oral administration of butterbur extract one-day post to the hypersensitivity induction. Ovalbumin induces a significant increase in the activity of liver enzymes and MDA and decreased the activity of CAT after the ovalbumin treatment. Histopathological investigations revealed marked pathological alterations in liver tissues in the form of hyaline degeneration and fibrosis. Additionally, heavy immune response indicated by immunostaining of MDA and TNF-α could be observed. In contrast, posttreatment with butterbur extract after hypersensitivity induction resulted in a significant decrease of liver enzymes and oxidative stress and reduced the inflammation and fibrosis of liver tissues. These results suggest that butterbur extract is considered as anti-inflammatory and antioxidant therapeutic herb for hypersensitivity treatment of liver.

Worldwide Use of RUCAM for Causality Assessment in 81,856 Idiosyncratic DILI and 14,029 HILI Cases Published 1993-Mid 2020: A Comprehensive Analysis

Background: A large number of idiosyncratic drug induced liver injury (iDILI) and herb induced liver injury(HILI) cases of variable quality has been published but some are a matter of concern if the cases were not evaluated for causality using a robust causality assessment method (CAM) such as RUCAM (Roussel Uclaf Causality Assessment Method) as diagnostiinjuryc algorithm. The purpose of this analysis was to evaluate the worldwide use of RUCAM in iDILI and HILI cases. Methods: The PubMed database (1993-30 June 2020) was searched for articles by using the following key terms: Roussel Uclaf Causality Assessment Method; RUCAM; Idiosyncratic drug induced liver injury; iDILI; Herb induced liver injury; HILI. Results: Considering reports published worldwide since 1993, our analysis showed the use of RUCAM for causality assessment in 95,885 cases of liver injury including 81,856 cases of idiosyncratic DILI and 14,029 cases of HILI. Among the top countries providing RUCAM based DILI cases were, in decreasing order, China, the US, Germany, Korea, and Italy, with China, Korea, Germany, India, and the US as the top countries for HILI. Conclusion: Since 1993 RUCAM is certainly the most widely used method to assess causality in IDILI and HILI. This should encourage practitioner, experts, and regulatory agencies to use it in order to reinforce their diagnosis and to take sound decisions.

Hepatobiliary Events in Migraine Therapy with Herbs-The Case of Petadolex, A Petasites Hybridus Extract

Petadolex^®, a defined butterbur extract has clinically proven efficacy against migraine attacks. However, spontaneous reports indicate cases of herbal induced liver injury (HILI). While most HILI patients presented mild serum biochemistry changes (<3 ULN, dose range 50 to 225 mg/day; treatment duration 4–730 days) nine developed severe HILI (average time-to-onset 103 days, ALT-range 3–153; AST 2–104-fold ULN). HILI cases resolved after medication withdrawal though two patients required liver transplantation. Liver biopsies revealed an inconsistent injury pattern, i.e. necrosis, macrovesicular steatosis, inflammation, cholestasis, and bile duct proliferation. Causality assessment rated 3 cases likely, 13 possible, 8 unlikely and 24 as unclassifiable/unclassified. Note, 22 patients reported hepatotoxic co-medications especially during periods of pain. A no-observable-adverse-effect-level at 15-fold of the maximal clinical dose (3 mg/kg/day MCD) was established for rats. At >45 and 90-fold MCD bile duct hyperplasia was observed but could not be confirmed in an explorative minipig study at 218-fold MCD. Human hepatocyte studies at 49-fold C_max serum petasins (=active ingredient) and therapeutic Ibuprofen, Paracetamol and Naratriptan concentrations evidenced liver transaminase and CYP-monooxygenase changes. Collectively, Petadolex^® HILI cases are rare, idiosyncratic and frequently confounded by co-medications. A physician-supervised self-medication plan with herbs and pain relief medication is needed to minimize risk for HILI.

Complementary and Integrative Medicine for Episodic Migraine: an Update of Evidence from the Last 3 Years

PURPOSE OF REVIEW

The purpose of this review is to evaluate evidence from the last 3 years on complementary and integrative medicine treatment options for episodic migraine. Using Pubmed, Embase, and Cochrane databases, research published from 2015-2018 evaluating the modalities of mind/body therapies, supplements, and manual therapies for treatment of migraine were assessed.

RECENT FINDINGS

Although many studies had major methodological challenges that limit interpretation, several studies reported decreased headache frequency, improved quality of life, or less affective responses to pain. The evidence is currently most promising for the mind/body treatment options of mindfulness, yoga, and tai chi. Mindfulness meditation may be as effective as pharmacological treatment for medication-overuse headache after the offending medication is withdrawn. While older research has shown magnesium, riboflavin, feverfew, and butterbur to be helpful in migraine treatment, new research is promising to suggest potential benefit with melatonin, vitamin D, higher dosages of vitamin B₆ (80 mg)/folic acid 5 mg combinations, and the combination of magnesium 112.5 mg/CoQ10 100 mg/feverfew 100 mg. Omega 3s have limited evidence of efficacy in migraine. Butterbur needs to be free of pyrrolizidine alkaloids (PA) to ensure safety given their hepatotoxicity. Physical therapy (PT) continues to have strong evidence of support, and acupuncture is superior to sham acupuncture and placebo. Side effects and risks reported were minimal and well tolerated overall, with the exception of the life-threatening risk of cervical artery dissection with high-velocity chiropractic manipulation and hepatotoxicity with the PAs in butterbur. Several studies are ongoing to further evaluate mindfulness, melatonin, PT, exercise, chiropractic manipulation, and acupuncture. The American Academy of Neurology (AAN) and American Headache Society (AHS) are currently updating the guidelines for integrative treatment options for migraine, so additional recommendations may be available soon. In conclusion, many complementary and integrative treatment options may be helpful for patients with migraines, and understanding potential efficacy, benefits, and risks can help providers discuss these modalities with their patients. Such a conversation can empower patients, build the therapeutic relationship, and increase self-efficacy, thus improving outcomes and patient-centered care.