Agranulocytosis and other consequences due to use of illicit cocaine contaminated with levamisole

Hydroxy levamisole and its phase II conjugates as potential indicators of levamisole doping in thoroughbred horses

RATIONALE

According to previous research, aminorex is the major metabolite of levamisole; however, in the screening of levamisole-positive racehorse urine and plasma samples, aminorex could only be detected in trace amounts or not at all. In forensic laboratories, hydroxy levamisole and its phase II conjugates make it easier to confirm levamisole misuse and to differentiate between the abuse of levamisole and aminorex. This study aimed to identify the major levamisole metabolites that can be detected along with the parent drug.

METHODS

The study describes levamisole and its metabolites in thoroughbred horses following oral administration and in vitro with equine liver microsomes. The plausible structures of the detected metabolites were postulated using liquid chromatography combined with high-resolution mass spectrometry.

RESULTS

Under the experimental conditions 26 metabolites (17 phase I, 2 phase II, and 7 conjugates of phase I metabolites) were detected (M1-M26). The major phase I metabolites identified were formed by hydroxylation. In phase II, the glucuronic acid conjugates of levamisole and hydroxy levamisole were detected as the major metabolites. In plasma, the parent drug and major metabolites are detectable for up to eight days, while in urine, they are detectable for up to twenty days. Levamisole levels rapidly increased at 45 min following administration, then declined gradually until detectable levels were reached approximately 8 days after administration, according to a pharmacokinetics study.

CONCLUSIONS

A prolonged elimination profile and relatively high concentration of hydroxy metabolites suggest that the detection of hydroxy metabolites is imperative for investigating levamisole doping in horses.

Ceftriaxone-Induced Reversible Agranulocytosis: A Case Report and Review of Drug-Induced Agranulocytosis

In the modern era of medicine, agranulocytosis is a rare occurrence. Despite significant improvement in patient survival, it still carries significant mortality. Agranulocytosis is most commonly caused by chemotherapeutic agents and numerous non-chemo drugs. As it can develop anytime during treatment and patients can remain asymptomatic, frequent cell count monitoring is an essential tool to make a timely diagnosis. An appropriate drug switch, work up to rule out infection and granulocyte colony-stimulating factor (G-CSF) injection in high-risk cases is the management. The patient should be kept under observation till the resolution of agranulocytosis. We present a case of ceftriaxone-induced agranulocytosis which was completely reversible upon stoppage of drug and granulocyte colony-stimulating factor administration. The pathogenesis of ceftriaxone-induced agranulocytosis is unknown. It is suggested to occur either by an immunologic mechanism or because of direct drug toxicity.

Abdominal Imaging Manifestations of Recreational Drug Use

Recreational drug use is a burgeoning health issue worldwide, with a variety of presenting symptoms and complications. These complications can be secondary to the toxic effects of the drug itself, drug impurities, and nonsterile injection. The abdominal radiologist is likely to encounter patients who use drugs recreationally and may be responsible for recognizing and reporting these acute conditions, which in some cases can be life threatening. Because these patients often present with an altered mental state and may deny or withhold information on drug use, the underlying cause may be difficult to determine. The most commonly used drugs worldwide include cocaine, cannabinoids, opioids, and amphetamines and their derivatives. Complications of use of these drugs that can be seen at abdominopelvic CT can involve multiple organ systems, including the soft tissue and gastrointestinal, genitourinary, vascular, and musculoskeletal systems. A diverse range of abdominal complications associated with these drugs can be seen at imaging, including disseminated infections, gastrointestinal ischemia, and visceral infarction. Radiologists should be familiar with the imaging findings of these complications to accurately diagnose these entities and help guide workup and patient treatment. ^©RSNA, 2020.

Potential Anti-SARS-CoV-2 Therapeutics That Target the Post-Entry Stages of the Viral Life Cycle: A Comprehensive Review

The coronavirus disease-2019 (COVID-19) pandemic continues to challenge health care systems around the world. Scientists and pharmaceutical companies have promptly responded by advancing potential therapeutics into clinical trials at an exponential rate. Initial encouraging results have been realized using remdesivir and dexamethasone. Yet, the research continues so as to identify better clinically relevant therapeutics that act either as prophylactics to prevent the infection or as treatments to limit the severity of COVID-19 and substantially decrease the mortality rate. Previously, we reviewed the potential therapeutics in clinical trials that block the early stage of the viral life cycle. In this review, we summarize potential anti-COVID-19 therapeutics that block/inhibit the post-entry stages of the viral life cycle. The review presents not only the chemical structures and mechanisms of the potential therapeutics under clinical investigation, i.e., listed in clinicaltrials.gov, but it also describes the relevant results of clinical trials. Their anti-inflammatory/immune-modulatory effects are also described. The reviewed therapeutics include small molecules, polypeptides, and monoclonal antibodies. At the molecular level, the therapeutics target viral proteins or processes that facilitate the post-entry stages of the viral infection. Frequent targets are the viral RNA-dependent RNA polymerase (RdRp) and the viral proteases such as papain-like protease (PLpro) and main protease (Mpro). Overall, we aim at presenting up-to-date details of anti-COVID-19 therapeutics so as to catalyze their potential effective use in fighting the pandemic.

A fatal case of levamisole induced bone marrow failure

A 20-year-old college student presented with high grade, intermittent fever for 10 days associated with blood stained loose stools after taking tablet levamisole for 17 days for vitiligo vulgaris. He was febrile, had a toxic appearance and appeared pale. Investigations showed neutropaenia with thrombocytopaenia. Blood cultures were sterile and stool cultures did not grow any enteric pathogens. His bone marrow examination was suggestive of an aplastic anaemia. He was administered empirical antibiotics, granulocyte colony stimulating factor and platelet transfusions. However, his fever and blood stained stools persisted. A repeat bone marrow examination after 2 weeks still revealed a hypoplastic marrow. Hence, a diagnosis of a levamisole induced bone marrow failure was made. While being worked up for an allogeneic stem cell transplantation, he developed neutropaenic enterocolitis and refractory septic shock with carbapenem resistant Klebsiella pneumoniae and succumbed to his illness.

Levamisole-induced vasculitis

Levamisole is a veterinary antihelminthic, chemotherapeutic agent, and immunomodulator that also is used as an adulterant and cutting agent in cocaine distribution. This drug may potentiate the sympathomimetic actions of cocaine and can cause neutropenia, agranulocytosis, purpuric retiform lesions, and skin necrosis. This article describes two cases of suspected levamisole-induced vasculitis. No standardized diagnostic or treatment algorithm exists for this challenging condition. Diagnosis and treatment require a multidisciplinary team approach.

Levamisole-Adulterated Cocaine Leading to Fatal Vasculitis: A Case Report

Cocaine is often "cut" with various additives to increase the profitability of the drug. One of the most common additives on today's market is levamisole, an anthelmintic medication used to destroy and expel parasitic worms in animals. The use of levamisole-contaminated cocaine can result in agranulocytosis and vasculitis (inflammation and constriction of small blood vessels). The resulting clotting and decrease in peripheral blood flow lead to cutaneous lesions, particularly on the ears, face, hands, and feet, and in severe cases can cause generalized tissue necrosis throughout the entire body. Treatment is generally supportive, and symptoms typically abate with complete cessation of cocaine use. However, symptoms may recur with subsequent cocaine use and, as this case illustrates, severe neutropenia and extensive vasculitis may lead to overwhelming sepsis and death.

A Case of Levamisole-Induced Agranulocytosis

A sixty-eight-year-old male with a past medical history of recurrent cocaine use presented to the emergency department with recurrent diarrhea and was found to have a white blood cell (WBC) count of 1.9 × 10⁹/L with agranulocytosis (absolute neutrophil count (ANC) of 95 cell/mm³). At admission, the patient disclosed that he used cocaine earlier during the day, and a urine drug screen tested positive for this. On hospital day one, the patient was found to have a fever with a maximum temperature of 313.6 K. After ruling out other causes and noting the quick turnaround of his neutropenia after four days of cocaine abstinence, the patient's neutropenia was attributed to levamisole-adulterated cocaine.

New frontiers in the treatment of colorectal cancer: Autophagy and the unfolded protein response as promising targets

Colorectal cancer (CRC), despite numerous therapeutic and screening attempts, still remains a major life-threatening malignancy. CRC etiology entails both genetic and environmental factors. Macroautophagy/autophagy and the unfolded protein response (UPR) are fundamental mechanisms involved in the regulation of cellular responses to environmental and genetic stresses. Both pathways are interconnected and regulate cellular responses to apoptotic stimuli. In this review, we address the epidemiology and risk factors of CRC, including genetic mutations leading to the occurrence of the disease. Next, we discuss mutations of genes related to autophagy and the UPR in CRC. Then, we discuss how autophagy and the UPR are involved in the regulation of CRC and how they associate with obesity and inflammatory responses in CRC. Finally, we provide perspectives for the modulation of autophagy and the UPR as new therapeutic options for CRC treatment.

A case of recurrent agranulocytosis due to levamisole

Agranulocytosis is a rare complication of levamisole. We report a 22-year-old female who developed agranulocytosis due to levamisole. The patient initially presented with salmonellosis and agranulocytosis, and then she recovered with treatment. However, 2 months after discharge, she again presented with tonsillitis and agranulocytosis. This time the family revealed that she had been taking levamisole. Though Salmonella infection is a recognized cause of agranulocytosis, any patient presenting with repeated agranulocytosis after an initial recovery should make the clinician suspect another cause, especially drug-induced. A case of Salmonella infection where levamisole was an unsuspecting cause of agranulocytosis has not been described in indexed literature. Recurrent agranulocytosis due to repeated exposure to levamisole has also not been described.

Tetramisole and Levamisole Suppress Neuronal Activity Independently from Their Inhibitory Action on Tissue Non-specific Alkaline Phosphatase in Mouse Cortex

Tissue non-specific alkaline phosphatase (TNAP) may be involved in the synthesis of GABA and adenosine, which are the main inhibitory neurotransmitters in cortex. We explored this putative TNAP function through electrophysiological recording (local field potential ) in slices of mouse somatosensory cortex maintained in vitro. We used tetramisole, a well documented TNAP inhibitor, to block TNAP activity. We expected that inhibiting TNAP with tetramisole would lead to an increase of neuronal response amplitude, owing to a diminished availability of GABA and/or adenosine. Instead, we found that tetramisole reduced neuronal response amplitude in a dose-dependent manner. Tetramisole also decreased axonal conduction velocity. Levamisole had identical effects. Several control experiments demonstrated that these actions of tetramisole were independent from this compound acting on TNAP. In particular, tetramisole effects were not stereo-specific and they were not mimicked by another inhibitor of TNAP, MLS-0038949. The decrease of axonal conduction velocity and preliminary intracellular data suggest that tetramisole blocks voltage-dependent sodium channels. Our results imply that levamisole or tetramisole should not be used with the sole purpose of inhibiting TNAP in living excitable cells as it will also block all processes that are activity-dependent. Our data and a review of the literature indicate that tetramisole may have at least four different targets in the nervous system. We discuss these results with respect to the neurological side effects that were observed when levamisole and tetramisole were used for medical purposes, and that may recur nowadays due to the recent use of levamisole and tetramisole as cocaine adulterants.

Trojan horses: drug culprits associated with antineutrophil cytoplasmic autoantibody (ANCA) vasculitis

PURPOSE OF REVIEW

Antineutrophil cytoplasmic autoantibody (ANCA) vasculitis is a systemic autoimmune disease resulting in small-vessel inflammation caused by pathogenic autoantibodies directed against proteinase 3 or myeloperoxidase. Legal drug culprits have been implicated as causative agents in secondary forms of disease, and a recent burst of reports also implicate levamisole-adulterated cocaine as a culprit.

RECENT FINDINGS

Here, we briefly discuss all drug culprits associated with ANCA vasculitis and then focus on clinical, serologic, therapeutic and mechanistic aspects of four main drug culprits receiving attention of late, namely hydralazine, minocycline, propylthiouracil (PTU) and levamisole-adulterated cocaine.

SUMMARY

Hydralazine, minocycline, propylthiouracil and levamisole-adulterated cocaine use should be closely considered in any patient where ANCA vasculitis is entertained given the wide use of these drugs in the community. Furthermore, medical practitioners should test urine for the presence of cocaine in any patient with presumed ANCA vasculitis, and if positive, then urine should also be tested for levamisole. Clinical features can be severe requiring not only drug cessation and supportive care, but also immunosuppression, plasma exchange in severe cases and dialysis as needed. Clinical trial investigators should strongly consider excluding patients with drug-induced forms of disease and mechanistic inroads are greatly needed in these secondary forms of disease to help elucidate the underlying cause and pathogenesis of ANCA vasculitis.

[Agranulocytosis and vasculitis in a cocaine addict: levamisole, the hidden culprit]

INTRODUCTION

Adulterants are compounds added to street drugs to increase profits for the seller. Levamisole, a veterinary antihelminthic agent, has become the most common adulterant of cocaine. The prevalence of levamisole in samples of cocaine is increasing. Levamisole can lead to neutropenia and to a dramatic vasculopathy and even vasculitis of small and medium-size blood vessels.

CASE REPORT

We here reported the first French case of levamisole related toxicity, due to cocaine use in a 50-year-old man, revealed by fever and agranulocytosis, high titters of antineutrophil cytoplasmic antibodies (ANCA), anticoagulant and positive Coombs tests. Outcome was slowly favorable with exposition withdrawal.

CONCLUSION

Clinicians should be aware that agranulocytosis or vasculitis or vasculopathy could be related to levamisole toxicity in individuals who use cocaine.

Aminorex, a metabolite of the cocaine adulterant levamisole, exerts amphetamine like actions at monoamine transporters

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We quantified adulterants in street drugs sold as cocaine.

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We analyzed effects of the most common adulterant levamisole, on neurotransmitter transporters.

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Differences in the selectivity of levamisole can be explained by homology modelling and docking.

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Aminorex, a metabolite of levamisole, modulates neurotransmitter transporters directly.

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Depending on the transporter, aminorex acts as a blocker or as a releaser.

Psychostimulants such as amphetamine and cocaine are illicitly used drugs that act on neurotransmitter transporters for dopamine, serotonin or norepinephrine. These drugs can by themselves already cause severe neurotoxicity. However, an additional health threat arises from adulterant substances which are added to the illicit compound without declaration. One of the most frequently added adulterants in street drugs sold as cocaine is the anthelmintic drug levamisole. We tested the effects of levamisole on neurotransmitter transporters heterologously expressed in HEK293 cells. Levamisole was 100 and 300-fold less potent than cocaine in blocking norepinephrine and dopamine uptake, and had only very low affinity for the serotonin transporter. In addition, levamisole did not trigger any appreciable substrate efflux. Because levamisole and cocaine are frequently co-administered, we searched for possible allosteric effects; at 30 μM, a concentration at which levamisole displayed already mild effects on norepinephrine transport it did not enhance the inhibitory action of cocaine. Levamisole is metabolized to aminorex, a formerly marketed anorectic drug, which is classified as an amphetamine-like substance. We examined the uptake-inhibitory and efflux-eliciting properties of aminorex and found it to exert strong effects on all three neurotransmitter transporters in a manner similar to amphetamine. We therefore conclude that while the adulterant levamisole itself has only moderate effects on neurotransmitter transporters, its metabolite aminorex may exert distinct psychostimulant effects by itself. Given that the half-time of levamisole and aminorex exceeds that of cocaine, it may be safe to conclude that after the cocaine effect “fades out” the levamisole/aminorex effect “kicks in”.

Cocaine-induced recurrent leukoencephalopathy

Cocaine-induced leukoencephalopathy is a rare neurological complication. It is most likely related to the substances used to adulterate the cocaine. Levamisole is one of the most common adulterants of cocaine and causes reversible leukoencephalopathy. Patients display severe neurological symptoms that resolve at termination of the exposure. MRI shows diffuse white matter involvement with sparing of the U fibers, without brain stem or cerebellar involvement. We describe the case of a woman with three neurologic episodes and remitting and recurrent brain white matter lesions.

Cocaine-induced recurrent leukoencephalopathy

Cocaine-induced leukoencephalopathy is a rare neurological complication. It is most likely related to the substances used to adulterate the cocaine. Levamisole is one of the most common adulterants of cocaine and causes reversible leukoencephalopathy. Patients display severe neurological symptoms that resolve at termination of the exposure. MRI shows diffuse white matter involvement with sparing of the U fibers, without brain stem or cerebellar involvement. We describe the case of a woman with three neurologic episodes and remitting and recurrent brain white matter lesions.

Cocaine-induced vasculitis: clinical and immunological spectrum

Levamisole-contaminated cocaine has recently been recognized in North America and Europe, and its use is associated with a variety of clinical and autoimmune abnormalities. The clinical characteristic seems to be the presence of a painful purpuric skin rash that predominantly affects the ear lobes and cheeks, often accompanied by systemic manifestations including fever, malaise, arthralgias, myalgias, and laboratory abnormalities, for example leukopenia, neutropenia, positive ANA, ANCA, and phospholipid antibodies. Most of these manifestations can be seen with the use of either drug, especially levamisole. There is no specific therapy, and discontinuation of its use is followed by improvement. Prednisone and immunosuppressive therapy may be needed at times. Further use of the drug is characterized by recurrence of most of the complaints.

The head, neck, and systemic manifestations of levamisole-adulterated cocaine use

Systemic complications of levamisole-adulterated cocaine (LAC) use have recently been described. The objective of this review is to increase awareness of these manifestations among oral and maxillofacial surgeons. LAC exposure through inhalation, nasal insufflation, or injection can induce cutaneous vasculopathy and hematologic abnormalities such as neutropenia or agranulocytosis. Unlike other vasculopathies involving the skin, LAC-induced vascular injury frequently manifests with purpuric and necrotic lesions that involve the face and ears. Oral manifestations have also been reported but are not yet well characterized. The aforementioned hematologic manifestations are not uncommon, and patients exposed to LAC are potentially at higher risk for infectious complications. When manifestations of LAC affect the head, neck, and oral cavity, oral and maxillofacial surgeons may be the first providers to encounter the patient. Early recognition of the clinical signs and laboratory abnormalities will better allow for distinguishing LAC-related effects from various clinical mimics, will facilitate appropriate patient management, and may further contribute to the understanding of the biological effects of LAC.