Strychnine poisoning due to traditional Chinese medicine: a case series

Background: Strychnine poisoning is rare but possibly fatal. The most reported sources of strychnine poisoning include rodenticides and adulterated street heroin. Here we report a case series of an unusual cause of strychnine poisoning – Strychnisemen, a herb known as “maqianzi” in traditional Chinese medicine (TCM).

Methods: All cases of strychnine poisoning confirmed by the Hospital Authority Toxicology Reference Laboratory (HATRL, the highest-level clinical toxicology laboratory in Hong Kong) between May 2005 and May 2018 were reviewed.

Results: Twelve cases of strychnine poisoning were recorded, and Strychni semen was the exclusive source. Ten (83%) patients presented with muscle spasms, and four (33%) developed typical conscious convulsions. The poisoning was severe in two (17%) patients, moderate in three (25%) and mild in eight (58%). No case fatality was recorded. Three (25%) patients were TCM practitioners and two (17%) were laymen who bought the herb themselves without a proper prescription.

Conclusion: The practice of TCM is becoming popular in different parts of the world amid the COVID-19 pandemic. The spectrum of clinical features of strychnine poisoning secondary to Strychni semen are similar to those arising from different origins. Eliciting a history of TCM use, apart from exposure to rodenticides and drugs of abuse, may allow timely diagnosis in patients with compatible clinical features. Enhancement of TCM safety could minimize the hazard.

Comparative Anticonvulsant Study of Epoxycarvone Stereoisomers

Stereoisomers of the monoterpene epoxycarvone (EC), namely (+)-cis-EC, (-)-cis-EC, (+)-trans-EC, and (-)-trans-EC, were comparatively evaluated for anticonvulsant activity in specific methodologies. In the pentylenetetrazole (PTZ)-induced anticonvulsant test, all of the stereoisomers (at 300 mg/kg) increased the latency to seizure onset, and afforded 100% protection against the death of the animals. In the maximal electroshock-induced seizures (MES) test, prevention of tonic seizures was also verified for all of the isomers tested. However, the isomeric forms (+) and (-)-trans-EC showed 25% and 12.5% inhibition of convulsions, respectively. In the pilocarpine-induced seizures test, all stereoisomers demonstrated an anticonvulsant profile, yet the stereoisomers (+) and (-)-trans-EC (at 300 mg/kg) showed a more pronounced effect. A strychnine-induced anticonvulsant test was performed, and none of the stereoisomers significantly increased the latency to onset of convulsions; the stereoisomers probably do not act in this pathway. However, the stereoisomers (+)-cis-EC and (+)-trans-EC greatly increased the latency to death of the animals, thus presenting some protection. The four EC stereoisomers show promise for anticonvulsant activity, an effect emphasized in the isomers (+)-cis-EC, (+)-trans-EC, and (-)-trans-EC for certain parameters of the tested methodologies. These results serve as support for further research and development of antiepileptic drugs from monoterpenes.

[Brucine chitosan thermosensitive hydrogel for intra-articular injection]

The aim of this study was to develop a sustained release converse thermosensitive hydrogel for intra-articular injection using chitosan-glycerol-borax as matrix, its physical properties and biocompatibility were investigated. Taking gelation time and gelation condition as index, the influence of concentration of chitosan, ratio of chitosan to glycerol, pH on physical properties of hydrogel were investigated. And then the in vitro drug release, rheological properties and biocompatibility were studied. The thermosensitive hydrogel flows easily at room temperature and turns to gelation at body temperature, which can certainly prolong the release of drug and has good biocompatibility.

Ayurvedic processed seeds of nux-vomica: neuropharmacological and chemical evaluation

The effect of detoxification on Strychnos nux-vomica seeds by traditional processing with aloe and ginger juices (B), by frying in cow ghee (C), and by boiling in cow milk (D) was investigated. The ethanolic extracts of these samples were subjected to spontaneous motor activity (SMA), pentobarbitone-induced hypnosis, PTZ induced convulsions, diazepam-assisted protection, and morphine-induced catalepsy. All samples reduced SMA and inhibited catalepsy. The seeds processed in milk (D) showed the lowest strychnine content in the cotyledons, exhibited marked inhibition of PTZ induced convulsions and maximal potentiation of hypnosis, and were the safest (LD(50)).

Neuropharmacological studies on Wedelia calendulacea Less stem extract

The neuropharmacological activities of the methanolic and aqueous extract of Wedelia calendulacea stem were screened in rats and mice. The extracts effect on pentobarbital-induced sleeping time, pentylenetetrazole- and styrychnine-induced seizure, spontaneous motor activity, exploratory behaviour, and rota-rod performance (motor coordination) were evaluated. The methanolic extract (20 and 50 mg/kg, i.p.) and aqueous extract (200 and 500 mg/kg, i.p.) produced a significant (p<0.001) prolongation of pentobarbital-induced sleeping time, and reduced the SMA and exploratory behaviour. The extract prolonged onset of the phases of seizure activity but did not protect mice against lethality induced by pentylenetetrazole and strychnine. It also failed to affect the motor coordination test. These results suggest that the extract contained an agent with neuropharmacological activity that may be sedative in nature. In addition, from the crude methanolic extract of Wedelia calendulacea stem a HPLC fingerprint profile and liquid chromatography/sequential mass spectrometry (LC/MS) were performed.

Effect of some convulsants on the protective activity of loreclezole and its combinations with valproate or clonazepam in amygdala-kindled rats

Loreclezole (5 mg/kg) exerted a significant protective action in amygdala-kindled rats, reducing both seizure and afterdischarge durations. The combinations of loreclezole (2.5 mg/kg) with valproate, clonazepam, or carbamazepine (applied at their subprotective doses) also exhibited antiseizure effect in this test. However, only two first combinations occurred to be of pharmacodynamic nature. Among several chemoconvulsants, bicuculline, N-methyl-D-aspartic acid and BAY k-8644 (the opener of L-type calcium channels) reversed the protective activity of loreclezole alone and its combination with valproate. On the other hand, bicuculline, aminophylline and BAY k-8644 inhibited the anticonvulsive action of loreclezole combined with clonazepam. The results support the hypothesis that the protective activity of loreclezole and its combinations with other antiepileptics may involve potentiation of GABAergic neurotransmission and blockade of L-type of calcium channels.

Design and synthesis of semicarbazones and their bio-isosteric analogues as potent anticonvulsants: the role of hydrogen bonding

A series of p-nitrophenyl substituted semicarbazones (4a-c) and phenoxy/p-bromophenoxy acetyl hydrazones (8a-q) were synthesized and their anticonvulsant activity was screened against maximal electroshock seizure (MES), subcutaneous metrazole (ScMet) and subcutaneous strychnine (ScSty) tests. Compounds 4a-c with -NHCO- were found to be the most active in all these tests. These compounds were also active in the MES test after oral administration in rats. On the other hand, compounds 8a-q with -OCH2- were devoid of anticonvulsant activity. The studies revealed that the hydrogen bonding domain in semicarbazones, adjacent to the lipophilic aryl ring, is essential for the anticonvulsant activity.

Quantifying fear potentiated startle using absolute versus proportional increase scoring methods: implications for the neurocircuitry of fear and anxiety

RATIONALE

The fear-potentiated startle paradigm [increased startle in the presence of a conditioned fear stimulus (CS)] has become increasingly popular as a tool for evaluating the potential efficacy of putative anxiolytic compounds. However, when the tested compounds also influence baseline startle, it is unclear how comparisons with control groups can best be made.

OBJECTIVE

To evaluate the validity of absolute difference (startle amplitude on CS minus non-CS test trials) vs. proportional increase (the absolute difference score divided by startle amplitude on non-CS test trials) scoring methods.

METHODS

The effect on proportional increase and absolute difference scores of baseline shifts that occur with or without concomitant increases in fear was evaluated in rats. A reliable measure should yield similar scores across shifting baselines, provided that fear levels remain constant.

RESULTS

Preexisting baseline differences, and those brought about by different startle-eliciting noise burst intensities, by strychnine injections, or by CRH infusions, each increased absolute difference scores without markedly influencing proportional change scores. These baseline differences were not associated with different fear levels. Increases in baseline startle brought about by unsignaled footshocks or by a second CS - increases which are associated with increased fear - partially occluded additional CS-induced increases using either measure.

CONCLUSIONS

Across different baselines, CS-elicited fear is most accurately reflected in proportional change scores. Under certain conditions saturation effects may interfere with an accurate assessment using either measure. However, these same saturation effects may provide opportunities to explore the neural circuitry of fear and anxiety in novel ways.

Herbal medicine causing likely strychnine poisoning

'Maqianzi' (the dried ripe seed of Strychnos nux-vomica L.) contains 1.0-1.4% each of strychnine and brucine. After processing to reduce its toxicity, 'maqianzi' was used as a herbal remedy for rheumatism, musculoskeletal injuries and limb paralysis. A 42-year old woman with neck pain was prescribed 15 g of 'maqianzi' to be taken in two doses at 7 hours apart, although the recommended dose was 0.3-0.6 g. She was apparently well after drinking the first of two bowls of 'maqianzi' decoction. One hour after she drank the second bowl of herbal decoction, she suddenly developed tonic contractions of all her limb muscles and carpopedal spasm lasting 5 min, difficulty in breathing, chest discomfort and perioral numbness. The second bowl of decoction probably became more concentrated because of evaporation of water during continued boiling and contained a larger amount of 'maqianzi'. On arrival in the hospital 1 hour later, she complained of muscle pain and tiredness. She was found to have hyperventilation and weakness of four limbs, with muscle power of grade 5(-)/5. All her symptoms gradually subsided over the next few hours. This case illustrated that 'maqianzi' can cause strychnine poisoning even after processing, especially when the recommended dose is greatly exceeded. In any patient with 'unexplained' muscle spasms or convulsions, strychnine poisoning should be included in the differential diagnosis and they should be asked about the use of herbal medicines.

[An experimental validation of pharmacological agents to arrest the vestibulo-autonomic syndrome (motion sickness)]

The results of development and experimental evaluation of the efficiency of pharmacological means of cupping the vestibulo-vegetative syndrome in man are presented. A model and procedure of evaluation of pharmacological cupping of the Vestibulo-vegetative syndrome are developed. The intramuscular injection of the mixture containing ephedrine, promethazine hydrochloride and strychnine (25, 50, and 1 mg, respectively) appeared most effective.

Strychnine-like multifocal myoclonus and seizures in extremely high-dose opioid administration: treatment strategies

While occasional myoclonic jerks are prevalent in cancer patients receiving opioids, severe myoclonic jerks and seizures due to opioids are uncommon. In this retrospective case series, we describe five cancer patients with refractory cancer pain and severe neuroexcitatory toxicity associated with extremely high-dose opioid therapy to characterize better the syndrome, its treatment, and its outcome. Two patients died following seizures, but three patients recovered following prompt treatment with parenteral midazolam infusions and rotation to alternative opioids. Possible mechanisms and treatment options for this potentially lethal clinical syndrome are reviewed. The authors conclude that severe multifocal myoclonus and seizures associated with extremely high-dose opioid therapy are life-threatening, and respond to parenteral midazolam infusion, rotation to alternative opioids, and aggressive supportive care.

Clinical toxicity of cocaine adulterants

Adulterants are found in all street samples of cocaine. They add an unappreciated dimension to the clinical toxicity of cocaine abuse. Identification of these adulterants is necessary to separate their effects from those of cocaine. The comprehensive toxic screen, which provides multiple modalities of drug analysis, will be a key diagnostic tool in the further investigation of these inherently toxic agents and their impact on syndromes of cocaine intoxication.

[Formation of epileptic activity complexes under the effect of the determinant focus in the cortex isolé]

In experiments on cats foci of enhanced excitation working in independent regimes were created in the neuronal-isolated cortex using weak strychnine solutions. Creation of a hyperactive focus by means of application of strychnine concentrated solutions or crystals leads to an increase in the amplitude and discharge frequency in other foci, synchronism in discharges of these foci and their unification into a single functional complex, working in the hyperactive focus regime. The latter, in such a way, presented the determinant structure. Under the influence of the determinaant focus there was also a marked generalization of the convulsive activity manifested by an embrace with epileptical discharges of the cortex area intact from strychnine. The results obtained indicate that the established relations between the foci of hyperactivity in the cortx as well as the effects of the determinant structure may be realized by the cortex mechanisms proper.

[Effect of different doses of strychnine on blood coagulation and lymph]

Tests conducted with dogs ascertained that strychnine used in a dose producing convulsions brings on an intensified coagulation of the blood and lymph along with a higher fibrinolytic activity. This reaction is largely due to the ejection of thromboplastic and fibrinolytic agents from the active muscles.

Drugs and reality in captive society. Some observations on chemical adaptation

The prison world is a captive society with its government, its policies, its sanctions, its language and its customs. It forms part of a greater population of ‘rounders’ who live in free society, are associated with criminal activity and have had previous prison experience.

The rounder justifies his actions with general statements: “there is no really honest man”; “honesty is just a fear of getting caught.” He is prevented from belonging to the free society once it has banished him to prison, and his criminal record and his past associations are never forgotten. He usually lives out his ‘rounder life’ because there is no other society for him. The prison custodial and professional staff are part of the ‘world in opposition’, and the inmate calls them ‘squares’, scoffs at their apparent honesty and well-meaning efforts, feels they are deceitful, untrustworthy and justifiable targets for opportunity, connivance and manipulation.

In parallel, the uses of drugs, chemicals and fermentations in prison have a distinctly different set of values and frame of reference than in free society. These variations and modifications in the use of drugs, together with the role of chemicals and poisons, reflect the ambivalent attitude which the inmate has towards the social system in general.

The Medical Officer must not allow himself to be identified as an inmate man or an institutional man. He cannot be party to any plan or activity either by the administration or the inmate population. He must function only in his role as doctor in the society of antagonists, and use his professional standards and his judgment to carry out his medical duties in his neutral position, to interpret the language of the two societies, one to the other, and prevent both groups from using the medical department for reasons of their own. The Medical Officer is truly the ‘third man’ in the institutional life.