Pharmacokinetic interaction between albendazole sulfoxide enantiomers and antiepileptic drugs in patients with neurocysticercosis

Follow up study of symptomatic human cystic echinococcosis treatment with albendazole and praziquantel, in Uruguay

BACKGROUND

Cystic echinococcosis (CE) is a chronic disease considered a neglected one. Cystic echinococcosis is endemic in Uruguay and the region. Surgery, using various technical approaches, has the potential to safely remove the cyst(s) and lead to a complete cure in a high number of patients with simple forms of CE. However, surgery may be impractical in patients with multiple cysts in several organs, high surgical risk, or in patients with previous multiple surgeries. In these cases, the pharmacological treatment with the benzimidazolic drug Albendazole (ABZ) alone or combined with Praziquantel (PZQ), has been promising as the best choice to achieve improvement or cure.

METHODS

In this study, we analyze the results obtained on the anti-parasitic treatment of 43 patients diagnosed with CE between the years 2003 and 2020. Patients were treated before and/or after surgery with ABZ or the combination ABZ/PZQ. The standardize protocol of the anti-parasitic drug treatment before surgery was 7 days, 15 days or 1 month depending on the urgency and availability of the surgical procedure. All cases that involved confirmed locations on lungs underwent immediate surgery with minimal pre-treatment when possible. After surgery, the standardize protocol of anti-parasitic drug treatment consisted of six cycles of 30 days each and resting intervals of 15 days in between. ABZ was used in all cases, administered orally, twice daily, at a total dosage of 15 mg/kg/day, with food high in fat content for improved absorption. The follow up was carried out according to WHO-IWGE guidelines for 5 years.

RESULTS

Of the 43 patients fourteen were ≤ 15 years of age and had a differentiated pre-surgical treatment. From the ≥ 16 years of age, 36 completed the treatments and the 5 years follow up. Four patients changed geographical locations, without a forwarding contact, after the post-surgery treatment. No patient died during the study. Of the 36 patients that completed the study, 32 were treated only with ABZ; 93.75% achieved treatment success as determined by improvement or cure, and 6.25% treatment failure determined by no change or worsening. The last four patients received the ABZ/PZQ combination therapy and achieved 100% treatment success.

CONCLUSION

The pharmacological treatment resulted in a good option not only as palliative but also as potentially curative. The main relevance of its use was in cases with previous multiple surgeries or surgeries with potential life-threatening complications due to the number and location of cysts and concurrent comorbidities. A follow-up of at least 5 years would be recommended to assure remission and control of the transmission. More randomized trials are needed to provide clear clinical evidence of different pharmacological treatments for CE.

The Impact of N-nitrosamine Impurities on Clinical Drug Development

Over the past few years, an increasing number of commercially available drugs have been reported to contain N-nitrosamine impurities above acceptable intake limits. Consequent interruption or discontinuation of the manufacturing and distribution of several marketed drugs has culminated into shortages of marketed drugs, including the antidiabetic drug metformin and the potentially life-saving drug rifampin for the treatment of tuberculosis. Alarmingly, the clinical development of new investigational products has been complicated as well by the presence of N-nitrosamine impurities in batches of marketed drug. In particular, rifampin is a key clinical index drug employed in drug-drug interaction (DDI) studies, and as a result of nitrosamine impurities regulatory bodies no longer accept the administration of rifampin in DDI studies involving healthy subjects. Drug developers are now forced to look at alternative approaches for commonly employed perpetrators, which will be discussed in this review.

Update on the diagnosis and management of neurocysticercosis

ABSTRACT Background: Neurocysticercosis (NCC) is a serious public health problem in several developing countries, including those in Latin America, Asia, and Africa. NCC is considered to be the main cause of late-onset epilepsy in endemic areas. Objective: This review summarizes recent advances in diagnosis and therapy of NCC. Methods: Relevant articles and books were reviewed and used as a source of information for this review. Results: The diagnosis of NCC is based upon neuroimaging studies (MRI and computed tomography) and laboratory analysis of the cerebrospinal fluid (CSF). Praziquantel and albendazole are considered parasiticidal drugs against NCC, but there is an intense debate over the value and safety of these drugs. Conclusion: Given the relative scarcity of clinical trials, more comparative interventional studies, especially randomized controlled trials in long-term clinical evolution, are required in order to clarify the controversy over the validity of parasitic therapy in patients with NCC.

Comparative Efficacy and Safety of Lacosamide and Oxcarbazepine for Seizure Control in Children with Newly Diagnosed Solitary Neurocysticercosis

BACKGROUND

In newly diagnosed neurocysticercosis (NCC) with seizures, the choice of anti-seizure medication (ASM) seems to be arbitrary due to a lack of comparative studies. Although oxcarbazepine (OXC) is often considered efficacious for focal seizures in NCC, due to adverse effects, newer ASMs like levetiracetam (LCM) and lacosamide are also being explored.

METHODS

This study was performed by case record review of children with newly diagnosed solitary viable parenchymal NCC aged 4-18years who received lacosamide and OXC at least for 12 weeks between August 2019 and April 2021, from a prospective registry of a tertiary care teaching hospital in north India. Seizure control, electroencephalographic abnormalities, resolution of inflammatory granulomas and adverse effects were compared between two arms at 12 and 24 weeks.

RESULTS

Total 31 (8.3 ± 4.7 years, 19 boys) and 72 (8.6 ± 4.2 years, 43 boys) completed at least 12 weeks follow-up in LCM and OXC groups, out of which 2 and 51 completed at least 24 weeks follow-up in LCM and OXC groups, respectively. The occurrence of breakthrough seizure was comparable in both arms at 12 and 24 weeks (1/31 and 2/22 in lacosamide group vs. 2/72 and 4/51 in OXC group, p = 0.66 and 0.59, respectively). Patients receiving OXC had more frequent treatment-emergent adverse events (p = 0.0001) and four patients required discontinuation due to severe adverse events (SAEs), while none in the lacosamide group had SAEs.

CONCLUSIONS

Lacosamide appears to be efficacious and safe for achieving seizure freedom in patients with solitary viable parenchymal neurocysticercosis.

Antiepileptic drugs for seizure control in people with neurocysticercosis

BACKGROUND

Neurocysticercosis is the most common parasitic infection of the brain. Epilepsy is the most common clinical presentation, though people may also present with headache, symptoms of raised intracranial pressure, hydrocephalus, and ocular symptoms depending upon the localisation of the parasitic cysts. Anthelmintic drugs, antiepileptic drugs (AEDs), and anti-oedema drugs, such as steroids, form the mainstay of treatment. This is an updated version of the Cochrane Review previously published in 2019.

OBJECTIVES

To assess the effects (benefits and harms) of AEDs for the primary and secondary prevention of seizures in people with neurocysticercosis. For the question of primary prevention, we examined whether AEDs reduce the likelihood of seizures in people who had neurocysticercosis but had not had a seizure. For the question of secondary prevention, we examined whether AEDs reduce the likelihood of further seizures in people who had had at least one seizure due to neurocysticercosis. As part of primary prevention studies, we also aimed to examine which AED was beneficial in people with neurocysticercosis in terms of duration, dose, and side-effect profile.

SEARCH METHODS

For the 2021 update of this review, we searched the Cochrane Register of Studies (CRS Web), MEDLINE, and LILACS to January 2021. CRS Web includes randomised or quasi-randomised, controlled trials from CENTRAL, the Specialised Registers of Cochrane Review Groups, including Epilepsy, PubMed, Embase, ClinicalTrials.gov, and the World Health Organisation International Clinical Trials Registry Platform. We also checked the reference lists of identified studies, and contacted experts and colleagues in the field to search for additional and ongoing studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials. Single-blind, double-blind, or unblinded studies were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We followed standard methodological procedures expected by Cochrane. Two review authors independently selected trials for inclusion and extracted the relevant data. The primary outcomes of interest were: proportion of individuals experiencing seizures, and time to first seizure post randomisation. Secondary outcomes included: seizure freedom, number of withdrawals, side effects, number of people seizure free with short or long durations of treatment, quality of life, therapy costs, hospitalisations, and mortality. We used an intention-to-treat analysis for the primary analysis. We calculated odds ratio (OR) for dichotomous data (proportion of individuals who experienced seizures, were seizure free for a specific time period (12 or 24 months), withdrew from treatment, developed drug-related side effects or complications, were seizure-free with each treatment policy, mortality), and planned to use mean difference (MD) for continuous data, if any continuous data were identified (quality of life, cost of treatment). We intended to evaluate time to first seizure after randomisation by calculating hazard ratios (HRs). We assessed precision using 95% confidence intervals (CIs). We stratified the analysis by treatment comparison. We also considered the duration of drug usage, co-medications, and the length of follow-up.

MAIN RESULTS

We did not find any trials that investigated the role of AEDs in preventing seizures among people with neurocysticercosis, presenting with symptoms other than seizures. We did not find any trials that directly compared individual AEDs for primary prevention in people with neurocysticercosis. We included four trials that evaluated the efficacy of short-term versus longer-term AED treatment for people with solitary neurocysticercosis (identified on computed tomography (CT) scan) who presented with seizures. In total, 466 people were enrolled. These studies compared AED treatment durations of 6, 12, and 24 months. The risk of seizure recurrence with six months of treatment compared with 12 to 24 months of treatment was inconclusive (odds ratio (OR) 1.34, 95% confidence interval (CI) 0.73 to 2.47; three studies, 360 participants; low-certainty evidence). The risk of seizure recurrence with six to 12 months of treatment compared with 24 months of treatment was inconclusive (OR 1.36, 95% CI 0.72 to 2.57; three studies, 385 participants; very low-certainty evidence). Two studies compared seizure recurrence with CT findings, and suggested that persistent and calcified lesions had a higher recurrence risk, and suggest longer duration of treatment with AEDs. One study reported no side effects, while the rest did not comment on side effects of the drugs. None of the studies addressed the quality of life of the participants. These studies had methodological deficiencies, such as small sample sizes, and a possibility of bias due to lack of blinding, which affect the results of the review.

AUTHORS' CONCLUSIONS

Despite neurocysticercosis being the most common cause of epilepsy worldwide, there is currently no evidence available regarding the use of AEDs as seizure prophylaxis among people presenting with symptoms other than seizures. For those presenting with seizures, there is no reliable evidence regarding the duration of treatment required. Therefore, there is a need for large scale randomised controlled trials to address these questions.

Neurocysticercosis and HIV/AIDS co-infection: A scoping review

OBJECTIVES

Neurocysticercosis (NCC) and human immunodeficiency virus (HIV) have a high disease burden and are prevalent in overlapping low- and middle-income areas. Yet, treatment guidance for people living with HIV/AIDS (PLWH/A) co-infected with NCC is currently lacking. This study aims to scope the available literature on HIV/AIDS and NCC co-infection, focusing on epidemiology, clinical characteristics, diagnostics and treatment outcomes.

METHODS

The scoping literature review methodological framework, and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. A total of 16,969 records identified through database searching, and 45 additional records from other sources were reduced to 52 included studies after a standardised selection process.

RESULTS

Two experimental studies, ten observational studies, 23 case series/case reports and 17 reviews or letters were identified. Observational studies demonstrated similar NCC seroprevalence in PLWH/A and their HIV-negative counterparts. Of 29 PLWH/A and NCC co-infection, 17 (59%) suffered from epileptic seizures, 15 (52%) from headaches and 15 (52%) had focal neurological deficits. Eighteen (62%) had viable vesicular cysts, and six (21%) had calcified cysts. Fifteen (52%) were treated with albendazole, of which 11 (73%) responded well to treatment. Five individuals potentially demonstrated an immune-reconstitution inflammatory syndrome after commencing antiretroviral therapy, although this was in the absence of immunological and neuroimaging confirmation.

CONCLUSIONS

There is a paucity of evidence to guide treatment of PLWH/A and NCC co-infection. There is a pressing need for high-quality studies in this patient group to appropriately inform diagnostic and management guidelines for HIV-positive patients with NCC.

The Effects of Nitric Oxide and Inhibitor, and Combination of Albendazole and Praziquantel On Liver in Mice Injected with Echinococcus granulosus Larvae

In this study, the role of nitric oxide (NO) in the pathogenesis of hydatidosis and the interaction with effects of anthelmintic drugs, albendazole and praziquantel, were examined in larval infection caused by protoscolices obtained from hydatid cysts of sheep liver in Albino Balb/c mice. Animals were divided into ten groups including controls and infected groups. Larval infection was established with intraperitoneal injection of protoscolices. Eight months after infection with protoscolices, the infected animals were divided into 6 groups. The infected animals were given a selective inhibitor of inducible nitric oxide synthase (iNOS) L-N⁶-(1-Iminoethyl) lysine-hydrochloride (L-NIL), NO donor sodium nitroprusside (SNP), albendazole and praziquantel as anthelmintic drugs for 7 days. In addition, control groups were composed of intact group, control, anthelmintic drugs + L-NIL, and anthelmintic drugs + SNP. The liver and blood samples were taken for cytological, histological, immunohistochemical and biochemical analyses 7 days after treatments at the end of experiment. The animals injected with protoscolices showed histopathological changes including inflammation areas, infiltration and accumulation of leukocytes, dilation of sinusoids, and damage in endothelial cells and hepatocytes at light microscopy. Electron microscopy were revealed severe damage in sinusoidal endothelial cells, leukocytes especially eosinophils in sinusoid lumens and disorganization in endoplasmic reticulum and nuclear membrane. Endothelial nitric oxide synthase (eNOS) and iNOS reactions were increased in the tissue. Anthelmintic drugs decreased inflammation areas and damages; however, it did not change NOS reactions in the animals given protoscolices. L-NIL and SNP diminished both iNOS and eNOS reactions. Unlike the group administered the inhibitor, SNP treated group exhibited less inflammation areas. Combination of these substances and drugs resulted in decreased inflammation areas. eNOS and iNOS reactions decreased in the drugs and SNP administered group, while only iNOS reaction was decreased in L-NIL given infection group. In addition, the infected groups which received SNP displayed expanded sinusoids and hepatocytes with vacuoles, intriguingly. While levels of serum nitrite/nitrate elevated only in the infection group given drugs and SNP, it decreased in the L-NIL administered group. Tissue level of malondialdehyde increased in infection groups with drugs and SNP. In conclusion, the results indicated that NO plays an important role in the pathogenesis of hydatidosis.

The effectiveness of anti-inflammatory and anti-seizure medication for individuals with single enhancing lesion neurocysticercosis: A meta-analysis and expert group-based consensus recommendations

Single brain enhancing lesions (SEL) are the most common presentation of neurocysticercosis (NCC) observed on neuroimaging in people presenting with epileptic seizures not only on the Indian sub-continent and in travelers returning from cysticercosis-endemic regions, but are also present in other parts of the world. The aim of this study, which consisted of a systematic review (CRD42019087665), a meta-analysis and an expert group consultation, was to reach consensus on the best anti-seizure medication and anti-inflammatory treatment for individuals with SEL NCC. Standard literature review methods were used. The Cochrane risk of bias tool was used and random effects model meta-analyses were performed. The quality of the body of evidence was rated using GRADE tables. The expert committee included 12 gender and geographically balanced members and recommendations were reached by applying the GRADE framework for guideline development. The 1-1.5-year cumulative incidence of seizure recurrence, cyst resolution or calcification following anti-seizure medication (ASM) withdrawal was not statistically different between ASM of 6, 12 or 24 months. In contrast, in persons whose cyst calcified post treatment, longer ASM decreased seizure recurrence. The cumulative incidence ratio (CIR) 1-1.5 years after stopping ASM was 1.79 95% CI: (1.00, 3.20) for patients given 6 versus 24 months treatment. Anti-inflammatory treatment with corticosteroids in patients treated with ASM compared to patients treated with ASM only showed a statistically significant beneficial effect on seizure reduction (CIR 0.44, 95% CI 0.23, 0.85) and cyst resolution (CIR 1.37, 95%CI: 1.07, 1.75). Our results indicate that ASM in patients with SEL NCC whose cysts resolved can be withdrawn, while patients whose cysts calcified seem to benefit from prolonged anti-seizure medication. Additional corticosteroid treatment was found to have a beneficial effect both on seizure reduction and cyst resolution.

Albendazole Sulfoxide Plasma Levels and Efficacy of Antiparasitic Treatment in Patients With Parenchymal Neurocysticercosis

BACKGROUND

The efficacy of albendazole therapy in patients with parenchymal neurocysticercosis (NCC) is suboptimal. Plasma levels of albendazole sulfoxide (ASOX), the active metabolite of albendazole, are highly variable among patients. We hypothesized that high ASOX plasma levels during albendazole therapy may be associated with an increased antiparasitic efficacy.

METHODS

ASOX plasma levels were measured at treatment day 7 in 118 patients with parenchymal NCC enrolled in a treatment trial. The relationships between increasing ASOX plasma levels with the proportion of cysts resolved and the proportion of patients with complete cyst resolution (evaluated by 6-month brain magnetic resonance) were assessed.

RESULTS

There was a trend toward a higher proportion of cysts resolved and a higher proportion of patients cured with increasing quartiles of ASOX plasma levels. In patients with 3 or more brain cysts, the regression analysis adjusted by the concomitant administration of praziquantel (PZQ) showed a 2-fold increase in the proportion of cysts resolved (risk ratio [RR], 1.98; 95% confidence interval [CI], 1.01-3.89; P = .048) and 2.5-fold increase in the proportion of patients cured (RR, 2.45; 95% CI, .94-6.36; P = .067) when ASOX levels in the highest vs the lowest quartile were compared. No association was found in patients with 1-2 brain cysts.

CONCLUSIONS

We suggest an association between high ASOX plasma levels and increased antiparasitic efficacy in patients with parenchymal NCC. Nonetheless, this association is also influenced by other factors including parasite burden and concomitant administration of PZQ. These findings may serve to individualize and/or adjust therapy schemes to avoid treatment failure.

Antiepileptic drugs for seizure control in people with neurocysticercosis

BACKGROUND

Neurocysticercosis is the most common parasitic infection of the brain. Epilepsy is the most common clinical presentation, though it may also present with headache, symptoms of raised intracranial pressure, hydrocephalus and ocular symptoms depending upon the localisation of the parasitic cysts. Anthelmintic drugs, anti-oedema drugs, such as steroids, and antiepileptic drugs (AEDs) form the mainstay of treatment.This is an updated version of the original Cochrane Review published in 2015, Issue 10.

OBJECTIVES

To assess the effects (benefits and harms) of AEDs for the primary and secondary prevention of seizures in people with neurocysticercosis.For the question of primary prevention, we examined whether AEDs reduce the likelihood of seizures in patients who have neurocysticercosis but have not had a seizure.For the question of secondary prevention, we examined whether AEDs reduce the likelihood of further seizures in patients who have had at least one seizure due to neurocysticercosis.As part of primary prevention studies, we also aimed to examine which AED has been found to be beneficial in people with neurocysticercosis in terms of duration, dose and side-effect profile.

SEARCH METHODS

For the latest update of this review, we searched the following databases on 8 July 2019: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid, 1946 to July 05, 2019) and LILACS (1982- ). CRS Web includes the Cochrane Epilepsy Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), and randomised or quasi-randomised, controlled trials from Embase, ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform (ICTRP). We also checked the references lists of identified studies, and contacted experts in the field and colleagues to search for additional studies and for information about ongoing studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials.Single-blind, double-blind or unblinded studies were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors screened all citations for eligibility (MS screened the initially identified 180 citations, MF and BDM screened the 48 citations identified for the purpose of this update).Two review authors independently extracted data and evaluated each study for risk of bias.

MAIN RESULTS

We did not find any trials that investigated the role of AEDs in preventing seizures among people with neurocysticercosis, presenting with symptoms other than seizures.We did not find any trials that evaluated evaluating individual AEDs in people with neurocysticercosis.We found one trial, comparing two AEDs in people with solitary neurocysticercosis with seizures. However, we excluded this study from the review as it was of poor quality.We found four trials that compared the efficacy of short term versus longer term AED treatment for people with solitary neurocysticercosis (identified on computed tomography (CT) scan) presenting with seizures. In total, 466 people were enrolled. These studies compared various AED treatment durations, six, 12 and 24 months. The risk of seizure recurrence with six months treatment compared with 12 to 24 months treatment was not statistically significant (odds ratio (OR) 1.34 (95% confidence interval (CI) 0.73 to 2.47; three studies, 360 participants; low-certainty evidence)). The risk of seizure recurrence with six to 12 months compared with 24 months treatment was not statistically significant (OR 1.36 (95% CI 0.72 to 2.57; three studies, 385 participants; low-certainty evidence)).Two studies co-related seizure recurrence with CT findings and suggested that persistent and calcified lesions had a higher recurrence risk and suggest longer duration of treatment with AEDs. One study reported no side effects, while the rest did not comment on side effects of drugs. None of the studies addressed the quality of life of the participants.These studies had certain methodological deficiencies such as a small sample size and a possibility of bias due to lack of blinding, which affect the results of this review.

AUTHORS' CONCLUSIONS

Despite neurocysticercosis being the most common cause of epilepsy worldwide, there is currently no evidence available regarding the use of AEDs as seizure prophylaxis among people presenting with symptoms other than seizures. For those presenting with seizures, there is no reliable evidence regarding the duration of treatment required. There is therefore a need for large scale randomised controlled trials to address these questions.

Design, synthesis and biological evaluation of imidazo[1,2-a]pyridine analogues or derivatives as anti-helmintic drug

The Albendazole was used as the lead compound, which was modified by structural transformation and with alkyl groups. A total of 18 compounds (4a-4r) were designed and synthesized. The in vitro experiment results showed that compounds 4e, 4f, 4k, 4l, 4q and 4r had good inhibitory effect on egg and imago of roundworm. IC₅₀ of compound 4l to anti-egg of roundworm was 0.65 ± 0.01 μmol/L and to anti-imago of roundworm was 1.04 ± 0.01 μmol/L. At the same time, it showed that compound 4l had the best effect in vivo, and the rate of anti-helmintic could reach more than 99%. The results of acute toxicity tests indicated that these compounds were with LD₅₀ > 2100 mg/kg by oral administration, so they were low toxicity compounds. In a word, compound 4l was most likely to be a new anti-helmintic drug through screening in vitro and in vivo.

Controversies in the treatment of seizures associated with neurocysticercosis

Seizures are the commonest manifestation of brain parenchymal cysticercosis. In terms of pathophysiological basis and prognostic significance of the seizures, a distinction might be applied between viable cysts, solitary cysticercus granuloma and calcific cysticerci. A number of uncertainties shroud the management of seizures in people with neurocysticercosis (NCC). Although antihelminthic treatment is effective in eliminating viable cysts and possibly cysticercus granulomas, its effect on seizure outcome remains uncertain. Corticosteroids and combinations of antihelminthic and corticosteroid treatments reduce the incidence of seizures in the short term at least. Although antiepileptic drugs (AEDs) are routinely employed in the treatment of seizures associated with NCC, there is no clear consensus regarding the choice and optimal duration of AED treatment. Long-term AED treatment is warranted in people with calcific residue following involution of brain parenchymal cysticercosis. This article is part of a Special Issue entitled "Neurocysticercosis and Epilepsy".

Antiepileptic drug therapy and recommendations for withdrawal in patients with seizures and epilepsy due to neurocysticercosis

INTRODUCTION

Neurocysticercosis (NCC) is a leading causes of secondary epilepsy worldwide. There is increasing evidence on the epileptogenic role of NCC, and the presence of edema, calcified scars, gliosis and hippocampal sclerosis support this phenomenon.

AREAS COVERED

We summarized principles of antiepileptic drug (AED) therapy as well as risk factors associated with seizure recurrence after AED withdrawal in patients with NCC. Expert commentary: First-line AED monotherapy is effective as a standard approach to control seizures in most NCC patients. Risks and benefits of AED withdrawal have not been systematically studied, and this decision must be individualized. However, a seizure-free period of at least two years seem prudent before attempting withdrawal. Risk factors for seizure recurrence after AED withdrawal include a history of status epilepticus, poor seizure control during treatment, neuroimaging evidence of perilesional gliosis, hippocampal sclerosis and calcified lesions, as well as persistence of paroxysmal activity in the EEG.

A review of pharmacokinetic drug-drug interactions with the anthelmintic medications albendazole and mebendazole

Medications indicated for helminthes and other parasitic infections are frequently being used in mass populations in endemic areas. Currently, there is a lack of guidance for clinicians on how to appropriately manage drug interactions when faced with patients requiring short-term anthelmintic therapy with albendazole or mebendazole while concurrently taking other agents. The objective of this review was to systematically summarize and evaluate published literature on the pharmacokinetics of albendazole or mebendazole when taken with other interacting medications. A search of MEDLINE (1946 to October 2014), EMBASE (1974 to October 2014), International Pharmaceutical Abstracts (1970 to October 2014), Google, and Google Scholar was conducted for articles describing the pharmacokinetics of albendazole or mebendazole when given with other medications (and supplemented by a bibliographic review of all relevant articles). Altogether, 17 articles were included in the review. Studies reported data on pharmacokinetic parameters for albendazole or mebendazole when taken with cimetidine, dexamethasone, ritonavir, phenytoin, carbamazepine, phenobarbital, ivermectin, praziquantel, diethylcarbamazine, azithromycin, and levamisole. Cimetidine increased the elimination half-life of albendazole and maximum concentration (Cmax) of mebendazole; dexamethasone increased the area under the plasma concentration-time curve (AUC) of albendazole; levamisole decreased the Cmax of albendazole; anticonvulsants (phenytoin, phenobarbital, carbamazepine) decreased the AUC of albendazole; praziquantel increased the AUC of albendazole; and ritonavir decreased the AUC of both albendazole and mebendazole. No major interactions were found with ivermectin, azithromycin, or diethylcarbamazine. Future research is required to clarify the clinical relevance of the interactions observed.

Routine drug and food interactions during antihelminthic treatment of neurocysticercosis: a reason for the variable efficacy of albendazole and praziquantel?

Neurocysticercosis (NC) or infection of the central nervous system with Taenia solium larvae is a leading cause of preventable seizures and epilepsy in endemic regions across the globe. Albendazole and praziquantel are commonly used antihelminthic agents to treat NC; however, viable cysts persist in the majority of patients, putting them at risk for future seizures and other neurological complications. Because of their pharmacokinetic profiles, albendazole and praziquantel have the potential to interact with many different drugs. During antihelminthic treatment, antiepileptic drugs and corticosteroids are commonly co-administered to manage seizures and cerebral edema; however, the most commonly used agents from these drug classes are known to significantly alter plasma concentrations of albendazole and praziquantel. The overarching issue with drug interactions during the treatment of NC is whether or not they have clinical relevance, as the plasma concentrations of albendazole and praziquantel have not been directly linked with eradication of viable cysts. Future studies should attempt to evaluate the validity of a causal relationship between antihelminthic plasma concentrations and outcomes so that drug interactions can be better understood and managed and so that treatment can be optimized.

Therapy for neurocysticercosis

Therapy for neurocysticercosis has advanced during the last 20 years with the advent of albendazole (Zentel) and praziquantel (Cysticide). Albendazole is the current medication of choice for the treatment of neurocysticercosis and is recommended for symptomatic patients with multiple viable cysts in the brain parenchyma. Albendazole may also be useful in extraparenchymal cysticercosis, especially in the subarachnoid racemose form, when complete surgical resection of the cysts is usually impracticable. Currently, there is an intense debate over the value and safety of anticysticercal therapy. Causes for failure of anticysticercal therapy include high inter-individual variability in plasma concentration of albendazole sulfoxide and the complex interactions of several drugs with the albendazole metabolite. Furthermore, albendazole sulfoxide is an enantiomeric mixture of (+)- and (-)-albendazole sulfoxide with accumulation of the (+)-enantiomer in the cerebrospinal fluid. However, the question over which enantiomer is effective against cysticerci remains to be clarified.

From seizures to epilepsy and its substrates: neurocysticercosis

Neurocysticercosis (NCC) is the main risk factor for late-onset seizures in many Taenia solium endemic countries and is also increasingly recognized in high income countries, where it was once thought to have been eliminated. The course and outcome of NCC-associated seizures and epilepsy are poorly understood. Substrates underlying NCC-associated seizures and epilepsy are unknown. Another unknown is if there is an association between NCC and hippocampal sclerosis (HS) and if it leads to intractable epilepsy. We review evidence regarding the structural basis of seizures and epilepsy in NCC and its association with HS. There are only a limited number of prospective studies of NCC-associated seizures and epilepsy. From these, it can be inferred that the risk of seizure recurrence is high following a first seizure, even though seizures are well-controlled with antiepileptic drugs. The single most important risk factor for ongoing or recurrent seizures is the persistence of either degenerating or residual calcified cysticercus cysts in the brain parenchyma on follow-up imaging studies. Medically intractable epilepsy requiring surgical treatment appears to be rare in people with NCC. In few cases that have been operated, gliosis around the cysticerci is the principal pathologic finding. Reports of the association between NCC and HS might be categorized into those in which the calcified cysticercus is located within the hippocampus and those in which the calcified cysticercus is located remote from the hippocampus. The former are convincing cases of medically intractable epilepsy with good seizure control following hippocampal resection. In the remaining, it is unclear whether a dual pathology relationship exists between HS and the calcified cysticercus. Carefully planned, follow-up studies incorporating high-resolution and quantitative imaging are desirable in order to clarify the outcome, the structural basis of NCC-associated epilepsy, and also its association with HS.

Drug-drug interactions between antiretrovirals and drugs used in the management of neglected tropical diseases: important considerations in the WHO 2020 Roadmap and London Declaration on Neglected Tropical Diseases

The group of infections known as the neglected tropical diseases (NTDs) collectively affect one billion people worldwide, equivalent to one-sixth of the world's population. The NTDs cause severe physical and emotional morbidity, and have a profound effect on cycles of poverty; it is estimated that NTDs account for 534 000 deaths per year. NTDs such as soil-transmitted helminth infections and the vector-borne protozoal infections leishmaniasis and trypanosomiasis occur predominantly in the most economically disadvantaged and marginalized communities. It is estimated that all low-income countries harbour at least five of the NTDs simultaneously. NTDs are neglected because they do not individually rank highly in terms of mortality data, and because they affect populations with little political voice. There is considerable geographic overlap between areas with high prevalence of NTDs and HIV, raising the possibility of complex polypharmacy and drug-drug interactions. Antiretrovirals pose a particularly high risk for potential drug-drug interactions, which may be pharmacokinetic or pharmacodynamic in nature and can result in raising or lowering plasma or tissue concentrations of co-prescribed drugs. Elevated drug concentrations may be associated with drug toxicity and lower drug concentrations may be associated with therapeutic failure. The aim of this paper is to review the currently available data on interactions between antiretrovirals and drugs used in the management of NTDs. It is intended to serve as a resource for policy makers and clinicians caring for these patients, and to support the recent WHO 2020 Roadmap and the 2012 London Declaration on NTDs.

Medical management of neurocysticercosis

INTRODUCTION

Neurocysticercosis (NCC) is considered to be the most common cause of acquired epilepsy worldwide. Formerly restricted to palliative measures, therapy for NCC has advanced with the advent of two drugs that are considered to be effective: praziquantel (PZQ) and albendazole (ALB).

AREAS COVERED

All available articles regarding research related to the treatment of NCC were searched. Relevant articles were then reviewed and used as sources of information for this review.

EXPERT OPINION

Anticysticercal therapy has been marked by intense controversy. Recent descriptions of spontaneous resolution of parenchymal cysticercosis with benign evolution, risks of complications and reports of no long-term benefits have reinforced the debate over the usefulness and safety of anticysticercal therapy. High interindividual variability and complex pharmacological interactions will require the close monitoring of plasma concentrations of ALB and PZQ metabolites in future trials. Given the relative scarcity of clinical trials, more comparative interventional studies - especially randomized controlled trials in long-term clinical evolution - are required to clarify the controversy over the validity of parasitic therapy in patients with NCC.

Albendazole-praziquantel interaction in healthy volunteers: kinetic disposition, metabolism and enantioselectivity

AIM

This study investigated the kinetic disposition, metabolism and enantioselectivity of albendazole (ABZ) and praziquantel (PZQ) administered alone and in combination to healthy volunteers.

METHODS

A randomized crossover study was carried out in three phases (n= 9), in which some volunteers started in phase 1 (400 mg ABZ), others in phase 2 (1500 mg PZQ), and the remaining volunteers in phase 3 (400 mg ABZ + 1500 mg PZQ). Serial blood samples were collected from 0-48 h after drug administration. Pharmacokinetic parameters were calculated using a monocompartmental model with lag time and were analyzed using the Wilcoxon test; P ≤ 0.05.

RESULTS

The administration of PZQ increased the plasma concentrations of (+)-ASOX (albendazole sulphoxide) by 264% (AUC 0.99 vs. 2.59 µg ml(-1) h), (-)-ASOX by 358% (0.14 vs. 0.50 µg ml(-1) h) and albendazole sulfone (ASON) by 187% (0.17 vs. 0.32 µg ml(-1) h). The administration of ABZ did not change the kinetic disposition of (+)-(S)-PZQ (-)-(R)-4-OHPZQ or (+)-(S)-4-OHPZQ, but increased the plasma concentration of (-)-(R)-PZQ by 64.77% (AUC 0.52 vs. 0.86 µg ml(-1) h).

CONCLUSIONS

The pharmacokinetic interaction between ABZ and PZQ in healthy volunteers was demonstrated by the observation of increased plasma concentrations of ASON, both ASOX enantiomers and (-)-(R)-PZQ. Clinically, the combination of ABZ and PZQ may improve the therapeutic efficacy as a consequence of higher concentration of both active drugs. On the other hand, the magnitude of this elevation may represent an increased risk of side effects, requiring, certainly, reduction of the dosage. However, further studies are necessary to evaluate the efficacy and safety of this combination.

A diagnostic and therapeutic scheme for a solitary cysticercus granuloma

BACKGROUND

Solitary cysticercus granuloma (SCG) is one of the most common forms of presentation of neurocysticercosis (NCC). The diagnostic workup and management approach to this condition remain uncertain and controversial.

OBJECTIVE

To review evidence and develop a consensus approach to the diagnosis and treatment of SCG.

METHODS

A multidisciplinary expert group meeting was convened in order to review and discuss various aspects of management of patients with SCG. Evidence reviewed was classified and a consensus was evolved according to standard protocols.

RESULTS

SCG is commonly recognized on CT as an enhancing lesion measuring <20 mm. Further evaluation with MRI does not add much information. The use of antihelminthic agents (specifically, albendazole in combination with corticosteroids) and corticosteroids alone have been shown to improve radiologic resolution and seizure outcome in patients with SCG. However, the sizes of the effects are modest. By convention, all patients with SCG presenting with seizures are initiated on antiepileptic drugs (AEDs). Available evidence suggests that withdrawal of AEDs after complete resolution of the SCG is safe. There is a high risk of seizure relapse after AED withdrawal in patients with calcific residue following resolution of the SCG. The duration of AED prophylaxis in these individuals is unclear.

CONCLUSIONS

It is desirable to have large, multicenter trials with sufficiently long follow-up, comparing outcomes with the use of antihelminthics with or without corticosteroids and corticosteroids alone in order to dissect out the benefits accrued due to each of these classes of drugs.

Treatment options for hepatic cystic echinococcosis

A number of surgical and non-surgical options exist to treat cystic echinococcosis of the liver. For decades, surgical excision via a conservative or radical approach was the recommended approach for hepatic hydatid cysts. The availability of chemotherapeutic agents with significant activity against Echinococcus granulosis has made it possible to undertake ultrasound- or computed tomography-guided transhepatic percutaneous drainage (termed puncture, aspiration, injection, and re-aspiration (PAIR)) of hydatid cysts. Pre- and post-intervention chemotherapy with albendazole or mebendazole offers the advantage of reducing the risk of disease recurrence and intraperitoneal seeding of infection that may develop via cyst rupture and spillage occurring spontaneously or during surgery or needle drainage. PAIR appears to have greater clinical efficacy (i.e. a higher incidence of cure), lower rates of major and minor complications, mortality, and disease recurrence, and fewer days of hospitalization compared to patients treated surgically. For patients who fail drug therapy alone, PAIR is a safe and effective procedure of choice for patients with hepatic echinococcosis, and perhaps other anatomic sites of infection such as lung, peritoneum, kidney, and other viscera. Surgery should be reserved for patients with hydatid cysts refractory to PAIR because of secondary bacterial infection or for those with difficult-to-manage cyst-biliary communication or obstruction.

Enantioselective renal excretion of albendazole metabolites in patients with neurocysticercosis

The present study investigates the urinary excretion of the enantiomers of (+)- and (-)-albendazole sulfoxide (ASOX) and albendazole sulfone (ASON) in 12 patients with neurocysticercosis treated with albendazole for 8 days (7.5 mg/kg/12 h). Serial blood samples (0-12 h) and urine (three periods of 8 h) were collected after administration of the last dose of albendazole. Plasma and urine (+)-ASOX, (-)-ASOX, and ASON metabolites were determined by HPLC using a chiral phase column (Chiralpak AD) with fluorescence detection. The pharmacokinetic parameters (P < 0.05) for (+)-ASOX, (-)-ASOX, and ASON metabolites are reported as means (95% CI); amount excreted (Ae) = 3.19 (1.53-4.85) vs. 0.72 (0.41-1.04) vs. 0.08 (0.03-0.13) mg; plasma concentration-time area under the curve, AUC(0-24) = 3.56 (0.93-6.18) vs. 0.60 (0.12-1.08) vs. 0.38 (0.20-0.55) microg x h/ml, and renal clearance Cl(R) = 1.20 (0.66-1.73) vs. 2.72 (0.39-5.05) vs. 0.25 (0.13-0.37) l/h. Sulfone formation capacity, expressed as the Ae ratio ASON/ASOX + ASON, was 2.21 (1.43-2.99). These data point to enantioselectivity in the renal excretion of ASOX as a complementary mechanism to the metabolism responsible for the plasma accumulation of (+)-ASOX. The results also suggest that the metabolite ASON is partially eliminated as a reaction product of the subsequent metabolism.

Diagnosis, treatment and control of Taenia solium cysticercosis

PURPOSE OF REVIEW

Taenia solium taeniasis/cysticercosis is now recognized as a major public health problem in most developing countries because of its association with seizures. Major advances in the diagnosis and epidemiology of taeniasis/cysticercosis have occurred in recent years. However, despite abundant literature on the subject, many questions remain unanswered including the role of anti-parasitic therapy and the potential for long-term control or elimination of the disease in field conditions following active interventions.

RECENT FINDINGS

Recent advances have included improved knowledge of the availability and optimization of diagnostic tools for the tapeworm stage, a better understanding of the meaning of antibody serology, the introduction of antigen detection assays, a consensus on the use of antiparasitic medication, awareness of inflammation and chronic scars around calcified cysts, population-based neuroimaging studies, application of control measures, and progress in the development of a pig vaccine.

SUMMARY

Neurocysticercosis is now much better understood than it was a few years ago. Infection and disease are now classified in terms of parasite viability, resulting in multiple and diverse clinical entities, each of which has a proper prognosis and management. As a result of this, the interpretation of diagnostic assays and imaging examinations is much more coherent. New aspects of this interesting disease have been recognized, mainly in relation to the frequency of calcified neurocysticercosis and its potential association with symptomatic relapses. Consensus diagnostic and treatment schemes have been proposed, and promising alternatives for control are currently being tested in several countries.

Clinically important drug interactions in epilepsy: interactions between antiepileptic drugs and other drugs

Antiepileptic drugs (AEDs) are commonly prescribed for long periods, up to a lifetime, and many patients will require treatment with other agents for the management of concomitant or intercurrent conditions. When two or more drugs are prescribed together, clinically important interactions can occur. Among old-generation AEDs, carbamazepine, phenytoin, phenobarbital, and primidone are potent inducers of hepatic enzymes, and decrease the plasma concentration of many psychotropic, immunosuppressant, antineoplastic, antimicrobial, and cardiovascular drugs, as well as oral contraceptive steroids. Most new generation AEDs do not have clinically important enzyme inducing effects. Other drugs can affect the pharmacokinetics of AEDs; examples include the stimulation of lamotrigine metabolism by oral contraceptive steroids and the inhibition of carbamazepine metabolism by certain macrolide antibiotics, antifungals, verapamil, diltiazem, and isoniazid. Careful monitoring of clinical response is recommended whenever a drug is added or removed from a patient's AED regimen.

A high performance liquid chromatography method for simultaneous determination of albendazole metabolites in human serum

A simple assay for albendazole (ABZ) main metabolites-albendazole sulphoxide (ABZ-SO), albendazole sulphone (ABZ-SO(2)) and albendazole amino sulphone (ABZ-SO(2)-NH(2))-in serum using high performance liquid chromatography was developed. The method involves liquid-liquid extraction of the serum by ethyl acetate, clean up with n-hexane and re-extraction with ethyl acetate, followed by separation on RP-C(8) column with a mixture of methanol: acetonitrile: acetic acid: water (40:1:10:49) as the eluting solvent. ABZ-SO and mebendazole-used as internal standard-were detected by UV (lambda=286 nm), and ABZ-SO(2) and ABZ-SO(2)-NH(2) with fluorescence spectrophotometer at (Excitation=286 nm, Emission=333 nm) and (Excitation=286 nm, Emission=315 nm), respectively. The assay was accurate and reproducible with a detection limit of 10 ng/ml for ABZ-SO, 2 ng/ml for ABZ-SO(2) and 4 ng/ml for ABZ-SO(2)-NH(2). Disregarding ABZ determination, which is not of pharmacokinetic importance as it is not found in human plasma after oral administration, the proposed method is appropriate for further pharmacokinetic and metabolism study of this drug.