Combination of probenecid-sulphadoxine-pyrimethamine for intermittent preventive treatment in pregnancy

Impact of Sulfadoxine-Pyrimethamine and Dihydroartemisinin-Piperaquine as Intermittent Preventive Treatment in Pregnancy on Stool Antimicrobial Resistance Gene Abundance

Increasing antimicrobial resistance (AMR) is a global public health emergency. Although chemoprevention has improved malaria-related pregnancy outcomes, the downstream effects on AMR have not been characterized. We compared the abundance of 10 AMR genes in stool samples from pregnant women receiving sulfadoxine-pyrimethamine (SP) as intermittent preventive treatment against malaria in pregnancy (IPTp) to that in samples from women receiving dihydroartemisinin-piperaquine (DP) for IPTp. All participants had at least one AMR gene at baseline. Mean quantities of the antifolate gene dfrA17 were increased after two or more doses of SP (mean difference = 1.6, 95% CI: 0.4-2.7, P = 0.008). Antimicrobial resistance gene abundance tended to increase from baseline in SP recipients compared with a downward trend in the DP group. Overall, IPTp-SP had minimal effects on the abundance of antifolate resistance genes (except for dfrA17), potentially owing to a high starting prevalence. However, the trend toward increasing AMR in SP recipients warrants further studies.

Drug repurposing for cardiovascular diseases: New targets and indications for probenecid

The available pharmacological options in the management of cardiovascular diseases such as ischaemic heart disease and subsequent heart failure are effective in slowing the progression of this condition. However, the long-term prognosis is still poor, raising the demand for new therapeutic strategies. Drug repurposing is a time- and cost-effective drug development strategy that offers approved and abandoned drugs a new chance for new indications. Recently, drugs used for the management of gout-related inflammation such as canakinumab or colchicine have been considered for drug repurposing in cardiovascular indications. The old uricosuric drug, probenecid, has been identified as a novel therapeutic option in the management of specific cardiac diseases as well. Probenecid can modulate myocardial contractility and vascular tone and exerts anti-inflammatory properties. The mechanisms behind these beneficial effects might be related inhibition of inflammasomes, and to modulation purinergic-pannexin-1 signalling and TRPV2 channels, which are recently identified molecular targets of probenecid. In this review, we provide an overview on repurposing probenecid for ischaemic heart disease and subsequent heart failure by summarizing the related experimental and clinical data and propose its potential repurposing to treat cardiovascular diseases.

CDER167, a dual inhibitor of URAT1 and GLUT9, is a novel and potent uricosuric candidate for the treatment of hyperuricemia

Urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) are important targets for the development of uric acid-lowering drugs. We previously showed that the flexible linkers of URAT1 inhibitors could enhance their potency. In this study we designed and synthesized CDER167, a novel RDEA3710 analogue, by introducing a linker (methylene) between the naphthalene and pyridine rings to increase flexibility, and characterized its pharmacological and pharmacokinetics properties in vitro and in vivo. We showed that CDER167 exerted dual-target inhibitory effects on both URAT1 and GLUT9: CDER167 concentration-dependently inhibited the uptake of [14C]-uric acid in URAT1-expressing HEK293 cells with an IC50 value of 2.08 ± 0.31 μM, which was similar to that of RDEA3170 (its IC50 value was 1.47 ± 0.23 μM). Using site-directed mutagenesis, we demonstrated that CDER167 might interact with URAT1 at S35 and F365. In GLUT9-expressing HEK293T cells, CDER167 concentration-dependently inhibited GLUT9 with an IC50 value of 91.55 ± 15.28 μM, whereas RDEA3170 at 100 μM had no effect on GLUT9. In potassium oxonate-induced hyperuricemic mice, oral administration of CDER167 (10 mg·kg-1 · d-1) for 7 days was more effective in lowering uric acid in blood and significantly promoted uric acid excretion in urine as compared with RDEA3170 (20 mg·kg-1 · d-1) administered. The animal experiment proved the safety of CDER167. In addition, CDER167 displayed better bioavailability than RDEA3170, better metabolic stability and no hERG toxicity at 100 μM. These results suggest that CDER167 deserves further investigation as a candidate antihyperuricemic drug targeting URAT1 and GLUT9.

Safety and tolerability of available urate-lowering drugs: a critical review

INTRODUCTION

Urate-lowering therapy (ULT) is the cornerstone of gout management, which is a widespread chronic illness characterized by hyperuricemia, arthropathy, tophus development, and urolithiasis. Since asymptomatic increased serum urate levels are associated with a higher risk of cardiovascular, renal and metabolic disorders, a larger use of ULTs in the general population is expected in the near future.

AREAS COVERED

This review will focus on the safety and tolerability profile of the available urate-lowering drugs: xanthine oxidase inhibitors (XOIs), uricosuric agents and injectable uricases.

EXPERT OPINION

Older drugs for ULT like allopurinol are well studied and extensively described from typical adverse effects (mild skin rash) to unusual fatal reactions, while febuxostat seems to be overall well tolerated. More evidence is required to define the safety profile of topiroxostat, arhalofenate, tranilast, and sulfinpyrazone. Furthermore, there are some unanswered questions about the pharmacological interactions of probenecid and the hepatotoxicity of benzbromarone. Despite a limited use in clinical practice, combination therapy with lesinurad or verinurad and XOI is not frequently accompanied by side effects. Rasburicase and pegloticase are usually well tolerated with some specific exceptions. Before prescribing UL drugs, physicians should take into account their safety profile tailoring the treatment on the patient characteristics.

Amoxicillin and Ceftriaxone as Treatment Alternatives to Penicillin for Maternal Syphilis

There is no proven alternative to penicillin for treatment of maternal syphilis. We report 2 case-patients with maternal syphilis who were successfully treated without penicillin. We used amoxicillin and probenecid for the first case-patient and amoxicillin, probenecid, and ceftriaxone for the second case-patient.

Trimester-Specific Population Pharmacokinetics and Other Correlates of Variability in Sulphadoxine-Pyrimethamine Disposition Among Ugandan Pregnant Women

Background

Sulphadoxine–pyrimethamine (SP) is widely used as an intermittent preventive treatment for malaria in pregnancy (IPTp). However, pharmacokinetic studies in pregnancy show variable and often contradictory findings. We describe population and trimester-specific differences in SP pharmacokinetics among Ugandan women.

Methods

SP (three tablets) were administered to 34 nonpregnant and 87 pregnant women in the second trimester. Seventy-eight pregnant women were redosed in the third trimester. Blood was collected over time points ranging from 0.5 h to 42 days postdose. Data on the variables age, body weight, height, parity, gestational age, and serum creatinine, alanine transaminase and albumin levels were collected at baseline. Plasma drug assays were performed using high-performance liquid chromatography with ultraviolet detection. Population pharmacokinetic analysis was done using NONMEM software.

Results

A two-compartment model with first-order absorption and a lag time best described both the sulphadoxine and pyrimethamine data. Between trimesters, statistically significant differences in central volumes of distribution (V₂) were observed for both drugs, while differences in the distribution half-life and the terminal elimination half-life were observed for pyrimethamine and sulphadoxine, respectively. Significant covariate relationships were identified on clearance (pregnancy status and serum albumin level) and V₂ (gestational age) for sulphadoxine. For pyrimethamine, clearance (pregnancy status and age) and V₂ (gestational age and body weight) were significant. Considering a 25 % threshold for clinical relevance, only differences in clearance of both drugs between pregnant and nonpregnant women were significant.

Conclusion

While clinically relevant differences in SP disposition between trimesters were not seen, increased clearance with pregnancy and the increasing volume of distribution in the central compartment with gestational age lend support to the revised World Health Organization guidelines advocating more frequent dosing of SP for IPTp.

Pharmacokinetics of artesunate alone and in combination with sulfadoxine/pyrimethamine in healthy Sudanese volunteers

Artesunate (AS) in combination with sulfadoxine/pyrimethamine (SP) is the first-line therapy for management of uncomplicated Plasmodium falciparum malaria in Sudan. The objective of this study was to assess the potential impact of SP on the pharmacokinetics of AS and its active metabolite, dihydroartemisinin (DHA), in healthy adults. A single-dose, randomized, open-label, crossover study design with a washout period of three weeks was performed with 16 volunteers. After oral administration of AS alone or in combination with SP, Tmax values of AS and DHA were significantly prolonged in the combination group (P < 0.05). However, there was no significant effect on the other pharmacokinetic parameters (P > 0.05). The t1/2 values of AS and DHA were significantly higher in females than in males (P < 0.05). The present findings suggest that co-administration of SP with AS has no clinically relevant impact on the pharmacokinetics of AS or DHA in healthy persons.

Impact of folate supplementation on the efficacy of sulfadoxine/pyrimethamine in preventing malaria in pregnancy: the potential of 5-methyl-tetrahydrofolate

Malaria remains the leading cause of mortality and morbidity in children under the age of 5 years and pregnant women. To counterbalance the malaria burden in pregnancy, an intermittent preventive treatment strategy has been developed. This is based on the use of the antifolate sulfadoxine/pyrimethamine, taken at specified intervals during pregnancy, and reports show that this approach reduces the malaria burden in pregnancy. Pregnancy is also associated with the risk of neural tube defects (NTDs), especially in women with low folate status, and folic acid supplementation is recommended in pregnancy to lower the risk of NTDs. Thus, in malaria-endemic areas, pregnant women have to take both antifolate medication to prevent malaria and folic acid to lower the risk of NTDs. However, the concomitant use of folate and antifolate is associated with a decrease in antifolate efficacy, exposing pregnant women to malaria. Thus, there is genuine concern that this strategy may not be appropriate. We have reviewed work carried out on malaria folate metabolism and antifolate efficacy in the context of folate supplementation. This review shows that: (i) the folate supplementation effect on antifolate efficacy is dose-dependent, and folic acid doses required to protect pregnant women from NTDs will not decrease antifolate activity; and (ii) 5-methyl-tetrahydrofolate, the predominant form of folate in the blood circulation, could be administered (even at high dose) concomitantly with antifolate without affecting antifolate efficacy. Thus, strategies exist to protect pregnant women from malaria while maintaining adequate folate levels in the body to reduce the occurrence of NTDs.

Ciprofloxacin is actively transported across bronchial lung epithelial cells using a Calu-3 air interface cell model

Ciprofloxacin is a well-established broad-spectrum fluoroquinolone antibiotic that penetrates well into the lung tissues; still, the mechanisms of its transepithelial transport are unknown. The contributions of specific transporters, including multidrug efflux transporters, organic cation transporters, and organic anion-transporting polypeptide transporters, to the uptake of ciprofloxacin were investigated in vitro using an air interface bronchial epithelial model. Our results demonstrate that ciprofloxacin is subject to predominantly active influx and a slight efflux component.