Unraveling snake venom phospholipase A2: an overview of its structure, pharmacology, and inhibitors

Snake bite is a neglected disease that affects millions of people worldwide. WHO reported approximately 5 million people are bitten by various species of snakes each year, resulting in nearly 1 million deaths and an additional three times cases of permanent disability. Snakes utilize the venom mainly for immobilization and digestion of their prey. Snake venom is a composition of proteins and enzymes which is responsible for its diverse pharmacological action. Snake venom phospholipase A2 (SvPLA2) is an enzyme that is present in every snake species in different quantities and is known to produce remarkable functional diversity and pharmacological action like inflammation, necrosis, myonecrosis, hemorrhage, etc. Arachidonic acid, a precursor to eicosanoids, such as prostaglandins and leukotrienes, is released when SvPLA2 catalyzes the hydrolysis of the sn-2 positions of membrane glycerophospholipids, which is responsible for its actions. Polyvalent antivenom produced from horses or lambs is the standard treatment for snake envenomation, although it has many drawbacks. Traditional medical practitioners treat snake bites using plants and other remedies as a sustainable alternative. More than 500 plant species from more than 100 families reported having venom-neutralizing abilities. Plant-derived secondary metabolites have the ability to reduce the venom's adverse consequences. Numerous studies have documented the ability of plant chemicals to inhibit the enzymes found in snake venom. Research in recent years has shown that various small molecules, such as varespladib and methyl varespladib, effectively inhibit the PLA2 toxin. In the present article, we have overviewed the knowledge of snake venom phospholipase A2, its classification, and the mechanism involved in the pathophysiology of cytotoxicity, myonecrosis, anticoagulation, and inflammation clinical application and inhibitors of SvPLA2, along with the list of studies carried out to evaluate the potency of small molecules like varespladib and secondary metabolites from the traditional medicine for their anti-PLA2 effect.

Efficacy and safety of lopinavir-ritonavir in COVID-19: A systematic review of randomized controlled trials

BACKGROUND

Lopinavir-ritonavir is a repurposed drug for coronavirus disease-2019 (COVID-19). In this study, a pooled effect of lopinavir-ritonavir on mortality, virological cure, radiological improvement and safety profile in COVID-19 patients has been evaluated.

METHODS

The databases were searched for comparative randomized controlled studies evaluating the efficacy and/or safety of lopinavir-ritonavir in COVID-19 patients. The mortality outcome was pooled as a risk difference (RD) with 95% CI. The virological cure, radiological improvement and adverse events were pooled as risk ratio (RR) with 95% CI. All outcomes were pooled using the Mantle-Hanzle method random effect model. The heterogeneity was assessed using the I2 test.

RESULTS

Out of 82 full text assessed, seven studies were included in the analysis. The included studies had five different control interventions: supportive care (n=4), umifenovir (arbidol) (n=2), navaferon (recombinant anti-tumour and anti-virus protein) (n=1), lopinavir-ritonavir+novaferon (n=1) and lopinavir-ritonavir+interferon beta 1b+ribavirin (n=1). Lopinavir-ritonavir group did not show significant difference in mortality [RD: 0.00 (95% CI: -0.01, 0.02), I2=0], virological cure [RR: 1.06 (95% CI: 0.85, 1.31), I2=0%], radiological improvement [RR: 0.81 (95% CI: 0.62, 1.05)] and adverse events [RR: 2.59 (95% CI: 0.17, 38.90), I2=75%] than supportive care. Similarly, no difference was observed for any efficacy outcomes between lopinavir-ritonavir and other control interventions. We observed significantly high risk of adverse events with lopinavir-ritonavir as compared to umifenovir [RR: 2.96 (95% CI: 1.42-6.18); I2=0%].

CONCLUSION

There is no benefit of the addition of lopinavir-ritonavir to the standard care in COVID-19 patients.

Efficacy and safety outcomes with remdesivir in COVID-19 patients: A meta-analysis

BACKGROUND

Remdesivir is a broad-spectrum antiviral drug having in vitro activity against severe acute respiratory syndrome coronavirus 2 and is currently being used on a compassionate basis outside of clinical trials.

AIM

To analyze the efficacy and safety of remdesivir compared with other interventions in coronavirus disease 2019 (COVID-19) patients.

METHODS

We searched online databases to include randomized controlled trials evaluating the efficacy and safety of remdesivir compared with other interventions in COVID-19 patients. We summarized efficacy and safety data as risk ratios (RRs) with 95% confidence interval (CI) and used Mantel-Haenszel fixed or random-effect models. We estimated the number needed to treat (NNT) to cause one additional outcome. We used the GRADE approach to assess the quality of the evidence for all outcome parameters.

RESULTS

We included four randomized controlled trials. We observed no significant difference in mortality (RR: 0.83; 95%CI: 0.57–1.20; I² = 59%) and rate of ventilation (RR: 0.69; 95%CI: 0.41-1.18; I² = 77%) between remdesivir- and placebo-treated patients. Remdesivir showed higher rates of clinical recovery than placebo (RR: 1.10; 95%CI: 1.04–1.16; I² = 0%; NNT: 14.3). We observed no difference in overall adverse events between remdesivir- and placebo-treated patients (RR: 1.05; 95%CI: 0.86–1.27; I² = 77%). We observed less risk of serious adverse events (RR: 0.75; 95%CI: 0.63–0.89; I² = 0%) in remdesivir- than placebo-treated patients. The GRADE approach suggested moderate quality of evidence for all efficacy and safety outcomes.

CONCLUSION

We observed limited clinical benefit of remdesivir over placebo in the treatment of COVID-19. Our findings could be biased because of the small number of trials.

Does Adding of Hydroxychloroquine to the Standard Care Provide any Benefit in Reducing the Mortality among COVID-19 Patients?: a Systematic Review

Hydroxychloroquine has been promoted for its use in treatment of COVID-19 patients based on in-vitro evidences. We searched the databases to include randomized and observational studies evaluating the effect of Hydroxychloroquine on mortality in COVID-19 patients. The outcome was summarized as odds ratios (OR) with a 95% confidence interval (CI).We used the inverse-variance method with a random effect model and assessed the heterogeneity using I² test. We used ROBINS-I tool to assess methodological quality of the included studies. We performed the meta-analysis using ‘Review manager software version 5.3’. We identified 6 observationalstudies satisfying the selection criteria. In all studies, Hydroxychloroquine was given as add on to the standard care and effect was compared with the standard care alone. A pooled analysis observed 251 deaths in 1331 participants of the Hydroxychloroquine arm and 363 deaths in 1577 participants of the control arm. There was no difference in odds of mortality events amongst Hydroxychloroquine and supportive care arm [1.25 (95% CI: 0.65, 2.38); I² = 80%]. A similar trend was observed with moderate risk of bias studies [0.95 (95% CI: 0.44, 2.06); I² = 85%]. The odds of mortality were significantly higher in patients treated with Hydroxychloroquine + Azithromycin than supportive care alone [2.34 (95% CI: 1.63, 3.34); I² = 0%]. A pooled analysis of recently published studies suggests no additional benefit for reducing mortality in COVID-19 patients when Hydroxychloroquine is given as add-on to the standard care.

Comparative Study between Mesotherapy and Topical 5% Minoxidil by Dermoscopic Evaluation for Androgenic Alopecia in Male: A Randomized Controlled Trial

Aim:

This study aims to compare efficacy and safety between mesotherapy (intralesional injection) and 5% topical minoxidil solution in male androgenic alopecia (AGA) by dermoscopic evaluation.

Methodology:

In a randomized active controlled trial, we enrolled 49 clinically diagnosed males of AGA and randomly allotted them into two groups – mesotherapy (A) (25) and minoxidil (B) (24). Males in Group A were given total 8 sessions of intralesional mesosolution with microneedling procedure while Group B males were prescribed topical solution of minoxidil 5% twice daily for 4 months. Results were evaluated at baseline and then monthly for 4 months with clinical photographs, dermoscopy, trichoscan, 7-point standard assessment tool, and patient-self assessment scores.

Results:

Grade II was the most common presentation in our study. All dermoscopic parameters such as variation of hair shaft diameter, follicular units with single and multiple hairs, yellow dots, and perifollicular halo did not show any significant difference between the groups at all time points except at 1^st month where the difference in variation of hair shaft diameter between the two group was 0.04. We observed a significant increase (P = 0.01) in the variation of hair shaft diameter between pre- and post-treatment in mesotherapy group compared to minoxidil group. The rest of parameters failed to show any significant difference within the group in mesotherapy and minoxidil.

Conclusion:

In our study, we observed a significant increase in the variation of hair shaft diameter between pre- and post-treatment in Group A compared to B. Other dermoscopic, trichoscan, and subjective measurement tool failed to show significant difference between two groups. Our observation suggests that there is no significant improvement of mesotherapy in male AGA over minoxidil.

Fenofibrate Nanocrystals Embedded in Oral Strip-Films for Bioavailability Enhancement

The aim of the present study was to make a fenofibrate (FNB) nanocrystal (NC) by wet media milling, characterizations and formulates into oral strip-films (OSFs). Mechanical properties, redispersion study, and solid-state characterizations results suggested that reduction of drug crystal size at nanoscale and incorporation into OSFs does not affect the solid-state properties of the drug. In vitro dissolution kinetics showed enhanced dissolution rate was easily manipulated by changing the thickness of the OSF. In situ UV-imaging was used to monitor drug dissolution qualitatively and quantitatively in real time. Results confirm that the intrinsic dissolution rates and surface drug concentration measured with this device were in agreement with the USP-IV dissolution profiles. In vivo pharmacokinetics in rabbits showed a significant difference in the pharmacokinetics parameter (1.4 fold increase bioavailability) of FNB NC-loaded OSFs as compared to the marketed formulation “Tricor” and as-received (pristine) drug. This approach of drug nanocrystallization and incorporation into OSFs may have significant applications in cost-effective tools for bioavailability enhancement of FNB.

Cardiovascular abnormalities with single dose of tapentadol

This case represents the development of dizziness, palpitation, tightness in chest, flushing, and tremor on consumption of a single dose of tapentadol (100 mg) for acute lower back pain. The patient was admitted in the intensive cardiac care unit for continuous monitoring. At admission, electrocardiogram showed tachycardia (140/min) along with ST segment elevation in second chest lead (V2). The patient was monitored and advised not to take further doses of tapentadol. He was discharged after 36 hours of admission. Tapentadol should be used cautiously in patients with cardiovascular diseases and receiving sympathomimetic drugs.

Effectiveness and tolerability of short course co-trimoxazole, norfloxacin and levofloxacin in bacteriological cure of uncomplicated urinary tract infection in outpatient setting. An open label, parallel group, randomized controlled trial

To compare the bacteriological cure rate of short-course (3-day) treatment of uncomplicated urinary tract infection (UTI) using co-trimoxazole, norfloxacin and levofloxacin, patients with uncomplicated UTI were randomized to receive either co-trimoxazole (960 mg) twice a day or norfloxacin (400 mg) twice a day or levofloxacin (250 mg) once a day for three days. Urine culture was done at the end of treatment and evaluated for bacteriological cure rate in each group. Among a total of 175 patients, Escherichia coli (74.29%) was the most common organism isolated followed by Klebsiella (11.43%), Streptococcus (6.29%), Staphylococcus saphrophyticus (5.14%), and Pseudomonas (2.86%). At the end of three days' treatment, bacteriological cure rates were 86.2%, 87.7% and 83.3% for co-trimoxazole, norfloxacin and levofloxacin, respectively (p>0.05). Therefore short-course treatment with co-trimoxazole 960 mg twice a day, norfloxacin 400 mg twice a day and levofloxacin 250 mg once a day are almost equally effective for treatment of uncomplicated UTI.

Drug-induced Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and SJS-TEN overlap: a multicentric retrospective study

BACKGROUND

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare immune-mediated severe cutaneous adverse reactions with incidence rate of 0.05 to 2 persons per million populations per year. Drugs are the most commonly implicated in 95% of cases.

AIMS

To audit the causative drugs, clinical outcome, and cost of management in SJS, TEN, and SJS-TEN overlap.

SETTING AND DESIGN

Tertiary care hospitals-based multicentric retrospective study (case series).

MATERIALS AND METHODS

Indoor case papers of SJS, TEN, and SJS-TEN overlap admitted between January 2006 and December 2009 in four tertiary care hospitals of Gujarat were scrutinized. Data were collected for demographic information, causative drugs, investigations, treatment given, duration of hospital stay, time interval between onset of symptoms and drug intake, clinical outcome, and complications. Data were analyzed to find out proportion of individual drugs responsible, major complications, and clinical outcome in SJS, TEN, and SJS-TEN overlap. Total cost of management was calculated by using cost of drugs, investigations, and consumables used during entire hospital stay.

STATISTICAL ANALYSIS

One-way Analysis of Variance followed by Tukey-Kramer multiple comparison test was used for comparison of incubation period, duration of hospital stay, and cost of management.

RESULTS

Antimicrobials (50%), nonsteroidal anti-inflammatory drugs (22.41%), and antiseizure drugs (18.96%) were the most commonly associated groups. Nevirapine (28.12%) was the most common drug. Antiseizure drugs were more often associated with serious form of adverse reaction (TEN: 81.8%) than other drugs. Duration of hospital stay (20.6 vs 9.7 days) and cost of management (7,910/- vs 2,460/-) were significantly higher in TEN than SJS (P=0.020 and P<0.001, respectively). Time duration between drug intake and onset of symptoms (17.7 vs 27.5 days) was nonsignificantly lower in TEN as compared with SJS. Secondary infection (28.12%) was the most common complication noted. Mortality rate was 15.6% among all cases; 9% in SJS and 26.7% in TEN.

CONCLUSION

Antimicrobial drugs are the most commonly implicated drugs and cost of managing these adverse drug reactions is higher than other serious ADRs.

Phenytoin induced chorea in a pediatric patient: An interaction between phenytoin, phenobarbital and clobazam

A 3-year-old female patient developed chorea possibly due to an interaction between phenytoin, phenobarbital and clobazam used for generalized tonic clonic seizures. Phenytoin withdrawal resulted in recovery within 24 hours. Post reaction computerized tomography (CT)-scan of brain was normal. Combined use of anti-seizure drugs and interactions between them may be responsible for the reaction. Therapeutic drug monitoring is important while prescribing two or more anti-seizure drugs.