A floating 3D printed polypill formulation for the coadministration and sustained release of antihypertensive drugs.

Polypharmacy is a common issue, especially among elderly patients resulting in administration errors and patient inconvenience. Hypertension is a prevalent health condition that frequently leads to polypharmacy, as its treatment typically requires the co-administration of more than one different Active Pharmaceutical Ingredients (API's). To address these issues, floating hollow torus-shaped dosage forms were developed, aiming at providing prolonged gastric retention and sustained drug release. The dosage forms (polypills) containing three anti-hypertensive API's (diltiazem (DIL), propranolol (PRP) and hydrochlorothiazide (HCTZ)) were created via Fused Deposition Modelling 3D printing. A multitude of the dosage forms were loaded into a capsule and the resulting formulation achieved prolonged retention times over a 12-hour period in vitro, by leveraging both the buoyancy of the dosage forms, and the "cheerios effect" that facilitates the aggregation and retention of the dosage forms via a combination of surface tension and shape of the objects. Physicochemical characterization methods and imaging techniques were employed to investigate the properties and the internal and external structure of the dosage forms. Furthermore, an ex vivo porcine stomach model revealed substantial aggregation, adhesion and retention of the 3D printed dosage forms in porcine stomach. In vitro dissolution testing demonstrated almost complete first-order release of PRP and DIL (93.52 % and 99.9 %, respectively) and partial release of HCTZ (65.22 %) in the 12 h timeframe. Finally, a convolution-based single-stage approach was employed in order to predict the pharmacokinetic (PK) parameters of the API's of the formulation and the resemblance of their PK behavior with previously reported data.

Platelet-activating factor contracts guinea pig esophageal muscularis mucosae by stimulating extracellular Ca2+ influx through diltiazem-insensitive Ca2+ channels.

Platelet-activating factor (PAF) is expected to increase esophageal motility. However, to the best of our knowledge, this has not been examined. Thus, we investigated the contractile effects of PAF on guinea pig (GP) esophageal muscularis mucosae (EMM) and the extracellular Ca2+ influx pathways responsible. PAF (10-9-10-6 M) contracted EMM in a concentration-dependent manner. PAF (10-6 M)-induced contractions were almost completely suppressed by apafant (a PAF receptor antagonist, 3 × 10-5 M). In EMM strips, PAF receptor and PAF-synthesizing/degrading enzyme mRNAs were detected. PAF (10-6 M)-induced contractions were abolished by extracellular Ca2+ removal but were not affected by diltiazem [a voltage-dependent Ca2+ channel (VDCC) inhibitor, 10-5 M]. PAF (10-6 M)-induced contractions in the presence of diltiazem were significantly suppressed by LOE-908 [a receptor-operated Ca2+ channel (ROCC) inhibitor, 3 × 10-5 M], SKF-96365 [an ROCC and store-operated Ca2+ channel (SOCC) inhibitor, 3 × 10-5 M], and LOE-908 plus SKF-96365. Among the tested ROCC/SOCC-related mRNAs, Trpc3, Trpc6, and Trpv4/Orai1, Orai3, and Stim2 were abundantly expressed in EMM strips. These results indicate that PAF potently induces GP EMM contractions that are dependent on extracellular Ca2+ influx through ROCCs/SOCCs, and VDCCs are unlikely to be involved.

Anti-hypertensive therapy for preeclampsia: a network meta-analysis and systematic review.

BACKGROUND: Preeclampsia (PE) is a pregnancy disorder that represents a major cause of maternal and perinatal morbidity and mortality. METHODS: This network meta-analysis was registered with PROSPERO. We searched the PubMed, ClinicalTrials.gov. and Embase databases for studies published from inception to the 31st of March 2023. RevMan5.3 software provided by the Cochrane Collaboration was used for direct meta-analysis (DMA) statistical analysis. Funnel maps, network meta-analysis (NMA), the surface under the cumulative ranking curve (SUCRA) to rank the different interventions and publication bias were generated by STATA 17.0 software. RESULTS: We included eight randomized controlled trials (RCTs) involving a total of 1192 women with PE; two studies were of high quality and six were of moderate quality. Eight interventions were addressed in the NMA. In the DMA, we found that blood pressure in the Ketanserin group were significantly higher than those in the Nicardipine group. NMA showed that blood pressure in the Dihydralazine group was significantly higher than that in the Methyldopa, Labetalol, Nicardipine and Diltiazem groups. And the blood pressure in the Labetalol group was significantly lower than that in the Nicardipine group. SUCRA values showed that Diltiazem was more effective in lowering blood pressure than other drugs looked at in this study. CONCLUSION: According to the eight RCTs included in this study, Diltiazem was the most effective in reducing blood pressure in PE patients; Labetalol and Nicardipine also had good effects. Diltiazem is preferred for the treatment of patients with severe PE and high blood pressure.

Efficacy of diltiazem 2% rectal gel in the treatment of chronic anal fissure: a retrospective observational study.

OBJECTIVE: The aim of this study is to describe the effectiveness and safety of a magistral formulation of diltiazem 2% rectal gel as a treatment for chronic anal fissure. MATERIAL AND METHODS: A retrospective observational study of all patients that began treatment with diltiazem 2% gel during 2019. The primary endpoint of the study was anal fissure healing. We also looked for differences in effectiveness between those initiating treatment and those who had been previously treated, long-term effectiveness through a 2-year follow-up and frequency of adverse effects. RESULTS: Of the 166 patients included in the study, anal fissure healed in 72.9%. We detected adverse effects in 12 patients, the most common was local irritation. After 2 years of follow-up, 88% of patients did not relapse. CONCLUSION: In this study, use of topical diltiazem 2% has been shown to be effective and safe in the treatment of anal fissure and should be considered as the first line of therapy.

OBJETIVO: El objetivo de este estudio es describir la efectividad y la seguridad de una fórmula magistral de diltiazem 2% gel rectal, como tratamiento de la fisura anal crónica. MATERIAL Y MÉTODOS: Un studio observacional retrospectivo de todos los pacientes que comenzaron a ser tratados con diltiazem 2% gel durante el año 2019. La variable principal del estudio fue la cicatrización de la fisura anal. También se buscaron diferencias de efectividad entre aquellos que iniciaban el tratamiento y los que ya habían sido tratados previamente, efectividad a largo plazo mediante un seguimiento de 2 años y frecuencia de aparición de efectos adversos. RESULTADOS: De los 166 pacientes incluidos en el estudio, el 72,9% cicatrizaron la fisura anal. No detectamos diferencias estadísticamente significativas de efectividad entre los pacientes naive y aquellos que ya habían sido tratados. Detectamos efectos adversos en 12 pacientes, siendo el más frecuente la irritación local. Tras 2 años de seguimiento, el 88% de los pacientes no presentaron ninguna recaída. CONCLUSIÓN: En este estudio, el uso de diltiazem 2% tópico ha mostrado ser efectivo y seguro en el tratamiento de la fisura anal y debería considerarse como primera línea terapéutica.

Diltiazem HCl suppresses porcine reproductive and respiratory syndrome virus infection in susceptible cells and in swine.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a pathogen for swine, resulting in substantial economic losses to the swine industry. However, there has been little success in developing effective vaccines or drugs for PRRSV control. In the present study, we discovered that Diltiazem HCl, an inhibitor of L-type Ca2+ channel, effectively suppresses PRRSV replication in MARC-145, PK-15CD163 and PAM cells in dose-dependent manner. Furthermore, it demonstrates a broad-spectrum activity against both PRRSV-1 and PRRSV-2 strains. Additionally, we explored the underlying mechanisms and found that Diltiazem HCl -induced inhibition of PRRSV associated with regulation of calcium ion homeostasis in susceptible cells. Moreover, we evaluated the antiviral effects of Diltiazem HCl in PRRSV-challenged piglets, assessing rectal temperature, viremia, and gross and microscopic lung lesions. Our results indicate that Diltiazem HCl treatment alleviates PRRSV-induced rectal temperature spikes, pulmonary pathological changes, and serum viral load. In conclusion, our data suggest that Diltiazem HCl could serve as a novel therapeutic drug against PRRSV infection.

Opioid-free anesthesia with ultrasound-guided quadratus lumborum block in the supine position for lower abdominal or pelvic surgery: a randomized controlled trial.

In the past, quadratus lumborum block (QLB) was mostly used for postoperative analgesia in patients, and few anesthesiologists applied it during surgery with opioid-free anesthesia (OFA). Consequently, it is still unclear whether QLB in the supine position can provide perfect analgesia and inhibit anesthetic stress during surgery under the OFA strategy. To observe the clinical efficacy of ultrasound-guided quadratus lumborum block (US-QLB) in the supine position with OFA for lower abdominal and pelvic surgery. A total of 122 patients who underwent lower abdominal or pelvic surgery in People's Hospital of Wanning between March 2021 and July 2022 were selected and divided into a quadratus lumborum block group (Q) (n = 62) and control group (C) (n = 60) according to the random number table method. Both groups underwent general anesthesia combined with QLB in the supine position. After sedation, unilateral or bilateral QLB was performed via the ultrasound guided anterior approach based on images resembling a "human eye" and "baby in a cradle" under local anesthesia according to the needs of the operative field. In group Q, 20 ml of 0.50% lidocaine and 0.20% ropivacaine diluted in normal saline (NS) were injected into each side. In group C, 20 ml of NS was injected into each side. The values of BP, HR, SPO2, SE, RE, SPI, NRS, Steward score, dosage of propofol, dexmedetomidine, and rocuronium, the number of patients who needed remifentanil, propofol, or diltiazem, puncture point, block plane, duration of anesthesia, catheter extraction, and wakefulness during the operation were monitored. There were no significant differences in the general data, number of cases requiring additional remifentanil, propofol, or diltiazem treatment, as well as puncture point and puncture plane between the two groups (P > 0.05). HR, SBP, and DBP values were higher in group Q than in group C at T1; HR, SPI, and SE, while RE values were lower in group Q than in group C at T3, SE, and RE; the Steward score was higher in group Q than in group C at T4 and T5, and the difference was statistically significant (P < 0.05). The extubation and awake times were lower in group Q than in group C, and the difference was statistically significant (P < 0.05). The SE, RE, and SPI values were lower at T1, T2, T3, and T4 than at T0. The Steward scores at T4 and T5 were higher in group Q than in group C, and were lower than at T0, with a statistically significant difference (P < 0.05). There were significant differences in the effectiveness of postoperative analgesia between the two groups at t1, t3 and t4 (P < 0.05). US-QLB in the supine position with OFA is effective in patients undergoing lower abdominal or pelvic surgery with stable intraoperative vital signs, complete recovery and better postoperative analgesia.

SERCA-1 conformational change exerted by the Ca2+-channel blocker diltiazem affects mammalian skeletal muscle function.

In skeletal muscle (SM), inward Ca2+-currents have no apparent role in excitation-contraction coupling (e-c coupling), however the Ca2+-channel blocker can affect twitch and tetanic muscle in mammalian SM. Experiments were conducted to study how diltiazem (DLZ) facilitates e-c coupling and inhibits contraction. 1) In complete Extensor Digitorum Longus (EDL) muscle and single intact fibres, 0.03 mM DLZ causes twitch potentiation and decreases force during tetanic activity, with increased fatigue. 2) In split open fibres isolated from EDL fibres, DLZ inhibits sarcoplasmic reticulum (SR) Ca2+-loading in a dose-dependent manner and has a potentiating effect on caffeine-induced SR Ca2+-release. 3) In isolated light SR (LSR) vesicles, SERCA1 hydrolytic activity is not affected by DLZ up to 0.2 mM. However, ATP-dependent Ca2+-uptake was inhibited in a dose-dependent manner at a concentration where e-c coupling is changed. 4) The passive Ca2+-efflux from LSR was reduced by half with 0.03 mM diltiazem, indicating that SR leaking does not account for the decreased Ca2+-uptake. 5) The denaturation profile of the SERCA Ca2+-binding domain has lower thermal stability in the presence of DLZ in a concentration-dependent manner, having no effect on the nucleotide-binding domain. We conclude that the effect of DLZ on SM is exerted by crossing the sarcolemma and interacting directly with the SERCA Ca2+-binding domain, affecting SR Ca2+-loading during relaxation, which has a consequence on SM contractility. Diltiazem effect on SM could be utilized as a tool to understand SM e-c coupling and muscle fatigue.

Risk factors for anticoagulant-associated gastrointestinal hemorrhage: a systematic review and meta-analysis.

BACKGROUND/AIMS: There may be many predictors of anticoagulation-related gastrointestinal bleeding (GIB), but until now, systematic reviews and assessments of the certainty of the evidence have not been published. We conducted a systematic review to identify all risk factors for anticoagulant-associated GIB to inform risk prediction in the management of anticoagulation- related GIB. METHODS: A systematic review and meta-analysis were conducted to search PubMed, EMBASE, Web of Science, and Cochrane Library databases (from inception through January 21, 2022) using the following search terms: anticoagulants, heparin, warfarin, dabigatran, rivaroxaban, apixaban, DOACs, gastrointestinal hemorrhage, risk factors. According to inclusion and exclusion criteria, studies of risk factors for anticoagulation-related GIB were identified. Risk factors for anticoagulant-associated GIB were used as the outcome index of this review. RESULTS: We included 34 studies in our analysis. For anticoagulant-associated GIB, moderate-certainty evidence showed a probable association with older age, kidney disease, concomitant use of aspirin, concomitant use of the antiplatelet agent, heart failure, myocardial infarction, hematochezia, renal failure, coronary artery disease, helicobacter pylori infection, social risk factors, alcohol use, smoking, anemia, history of sleep apnea, chronic obstructive pulmonary disease, international normalized ratio (INR), obesity et al. Some of these factors are not included in current GIB risk prediction models. such as anemia, co-administration of gemfibrozil, co-administration of verapamil or diltiazem, INR, heart failure, myocardial infarction, etc. CONCLUSION: The study found that anemia, co-administration of gemfibrozil, co-administration of verapamil or diltiazem, INR, heart failure, myocardial infarction et al. were associated with anticoagulation-related GIB, and these factors were not in the existing prediction models. This study informs risk prediction for anticoagulant-associated GIB, it also informs guidelines for GIB prevention and future research.

Sustainable asymmetric synthesis of diltiazem precursor enabled by recombinant Escherichia coli whole cells co-expressing an engineered ketoreductase and glucose dehydrogenase.

As a key synthetic intermediate of the cardiovascular drug diltiazem, methyl (2R,3S)-3-(4-methoxyphenyl) glycidate ((2R,3S)-MPGM) (1) is accessible via the ring closure of chlorohydrin (3S)-methyl 2-chloro-3-hydroxy-3-(4-methoxyphenyl)propanoate ((3S)-2). We report the efficient reduction of methyl 2-chloro-3-(4-methoxyphenyl)-3-oxo-propanoate (3) to (3S)-2 using an engineered enzyme SSCRM2 possessing 4.5-fold improved specific activity, which was obtained through the structure-guided site-saturation mutagenesis of the ketoreductase SSCR by reliving steric hindrance and undesired interactions. With the combined use of the co-expression fine-tuning strategy, a recombinant E. coli (pET28a-RBS-SSCRM2 /pACYCDuet-GDH), co-expressing SSCRM2 and glucose dehydrogenase, was constructed and optimized for protein expression. After optimizing the reaction conditions, whole-cell-catalyzed complete reduction of industrially relevant 300 g L-1 of 3 was realized, affording (3S)-2 with 99% ee and a space-time yield of 519.1 g∙L-1 ∙d-1 , representing the highest record for the biocatalytic synthesis of (3S)-2 reported to date. The E-factor of this biocatalytic synthesis was 24.5 (including water). Chiral alcohol (3S)-2 generated in this atom-economic synthesis was transformed to (2R,3S)-MPGM in 95% yield with 99% ee.

Relaxant Effects of Piperine and Piperlongumine from Piper longum Fruits on Porcine Coronary Artery.

Since ancient times, Piper longum Linn. fruits have been recognized for exhibiting various effects, including the diaphoretic effects linked to enhanced blood flow. Piperine and piperlongumine coexist in Piper longum Linn. fruits, although the cardiovascular effects of both compounds remain elusive. We investigated their action of piperine and piperlongumine in porcine coronary arteries, comparing them to the Ca2+ channel antagonist diltiazem. Piperlongumine, unlike piperine or diltiazem, concentration-dependently inhibited basal contractile tone in endothelium-denuded coronary arteries. All three compounds inhibit tonic contractions induced by high potassium chloride (KCl) concentrations. The order of relaxation potency indexed by the half-maximal effective concentration (EC50) were as follows: diltiazem > piperlongumine > piperine. These effects were not different between endothelium-intact and -denuded preparations. In endothelial-denuded preparations, pretreatment with these compounds not only inhibited KCl-induced tonic contractions attenuated calcium chloride (CaCl2)-induced ones in a Ca2+-free medium. Histamine-induced phasic contractions in a Ca2+-free medium containing intracellular Ca2+ chelator was completely suppressed by selective inositol trisphosphate receptor antagonist and piperlongumine, whereas piperine or diltiazem do not have the same effect. These findings suggest that piperine and piperlongumine similar to diltiazem cause vasorelaxation by inhibiting both KCl- and CaCl2-induced contractions in coronary arteries, possibly through the inhibition of voltage-dependent Ca2+ channels. Piperlongumine inhibits histamine-induced contractions in a Ca2+-free medium, which is associated with the intracellular Ca2+ signaling pathway, suggesting that the relaxant effect of piperlongumine differs from that of piperine.

Intravenous Diltiazem Versus Metoprolol in Acute Rate Control of Atrial Fibrillation/Flutter and Rapid Ventricular Response: A Meta-Analysis of Randomized and Observational Studies.

BACKGROUND: Atrial fibrillation (AF) and/or atrial flutter (AFL) with rapid ventricular response (RVR) is a condition that often requires urgent treatment. Although guidelines have recommendations regarding chronic rate control therapy, recommendations on the best choice for acute heart rate (HR) control in RVR are unclear. METHODS: A systematic search across multiple databases was performed for studies evaluating the outcome of HR control (defined as HR less than 110 bpm and/or 20% decrease from baseline HR). Included studies evaluated AF and/or AFL with RVR in a hospital setting, with direct comparison between intravenous (IV) diltiazem and metoprolol and excluded cardiac surgery and catheter ablation patients. Hypotension (defined as systolic blood pressure less than 90 mmHg) was measured as a secondary outcome. Two authors performed full-text article review and extracted data, with a third author mediating disagreements. Random effects models utilizing inverse variance weighting were used to calculate odds ratios (OR) and 95% confidence intervals (CI). Heterogeneity was assessed using the I2 test. RESULTS: A total of 563 unique titles were identified through the systematic search, of which 16 studies (7 randomized and 9 observational) were included. In our primary analysis of HR control by study type, IV diltiazem was found to be more effective than IV metoprolol for HR control in randomized trials (OR 4.75, 95% CI 2.50-9.04 with I2 = 14%); however, this was not found for observational studies (OR 1.26, 95% CI 0.89-1.80 with I2 = 55%). In an analysis of observational studies, there were no significant differences between the two drugs in odds of hypotension (OR 1.12, 95% CI 0.51-2.45 with I2 = 18%). CONCLUSION: While there was a trend toward improved HR control with IV diltiazem compared with IV metoprolol in randomized trials, this was not seen in observational studies, and there was no observed difference in hypotension between the two drugs.

Role of magnesium alone or in combination with diltiazem and/or amiodarone in prevention of atrial fibrillation following off-pump coronary artery bypass grafting.

Objectives: In this study the authors have tried to examine the role of magnesium alone or in combination with diltiazem and / or amiodarone in prevention of atrial fibrillation (AF) following off-pump coronary artery bypass grafting (CABG). Background: AF after CABG is common and contributes to morbidity and mortality. Various pharmacological preventive measures including magnesium, amiodarone, diltiazem, and combination therapy among others have been tried to lower the incidence of AF. Most of the studies have been performed in patients undergoing conventional on-pump CABG. In this uncontrolled trial, efficacy of magnesium alone or in combination with amiodarone and / or diltiazem has been studied in patients undergoing off-pump CABG. Methods: One hundred and fifty patients undergoing off-pump CABG were divided into 3 groups, Group M (n=21) received intraoperative magnesium infusion at 30mg/ kg over 1 hour after midline sternotomy; Group MD (n=78) received magnesium infusion in similar manner with diltiazem infusion at 0.05 µg/kg/hr throughout the intraoperative period; Group AMD (n=51) received preoperative oral amiodarone at a dose of 200 mg three times a day for 3 days followed by 200 mg twice daily for another 3 days followed by 200 mg once daily till the day of surgery along with magnesium and diltiazem infusion as in other groups. AF lasting more than 10 min or requiring medical intervention was considered as AF. Results: The overall incidence of postoperative AF was 12.6% with 11.7% in group AMD, 19% in group M, and 11.5% in group MD, which was not statistically significant. Conclusions: It is concluded that the use of amiodarone and/or diltiazem in addition to magnesium did not result in additional benefit of lowering the incidence of AF.

Application of surgical pleth index in the opioid-free anesthesia: A randomized controlled trial.

BACKGROUND: Currently, there is no gold standard for monitoring noxious stimulation during surgery, and the surgical pleth index (SPI) is only one of many monitoring methods. It is commonly used in the monitoring of conventional opiate anesthesia, but its effectiveness in opioid-free anesthesia (OFA) has not been evaluated. Therefore, the aim of this study was to observe the guidance value of the surgical pleth index in opioid-free anesthesia for patients undergoing lower abdominal or pelvic surgery. METHODS: A total of 122 patients who underwent lower abdominal or pelvic surgery in our hospital between March 2021 and July 2022 were selected and equally divided into OFA (F) and control (C) groups according to the random number table method. Both groups underwent ultrasound-guided unilateral/bilateral quadratus lumborum block in the supine position according to the surgical field. In group F, 0.50% lidocaine and 0.20% ropivacaine (in 20 mL of 0.9% normal saline) were injected on each side. In group C, 20 mL 0.9% normal saline was injected on each side. Group F received general anesthesia without opioids and group C received general anesthesia with opioids. BP, pulse oxygen saturation, PETCO2, reactionentropy, stateentropy, and SPI values; Steward score; dosage of propofol, dexmedetomidine, rocuronium, and diltiazem; extubation time; and awake time were monitored in both groups. RESULTS: There were no significant differences in the general data between the 2 groups (P > .05). There were no significant differences in SPI values at T0, T1, T2, T3, T4, and T5 or the number of cases requiring additional remifentanil, propofol, and diltiazem between the 2 groups (P > .05). The stateentropy, reactionentropy, and Steward scores were higher in group F than in group C at T4 and T5, while the extubation and awake times were lower in group F than in group C (P < .05). The heart rate and SPI of group F were lower than that of group C at T3 (P < .05). CONCLUSION: The guiding value of SPI in OFA was similar to its use in opiated anesthesia. Its clinical efficacy is exact, vital signs are stable, enabling rapid, and complete regaining of consciousness.

Impact of posaconazole and diltiazem on pharmacokinetics of encorafenib, a BRAF V600 kinase inhibitor for melanoma and colorectal cancer with BRAF mutations.

Encorafenib is a potent and selective ATP competitive inhibitor of BRAF V600-mutant kinase approved for patients with BRAF-mutant melanoma and colorectal cancer. Encorafenib is mainly metabolized by cytochrome P450 (CYP) 3A4 in vitro and may be susceptible to drug-drug interactions when co-administered with CYP3A inhibitors or inducers. The primary objective was to assess the impact of the strong CYP3A inhibitor posaconazole (part 1) and the moderate CYP3A and P-gp inhibitor diltiazem (part 2) on encorafenib pharmacokinetics in healthy volunteers following a single 50-mg dose. A total of 32 participants were enrolled (16 each in parts 1 and 2). The area under the curve extrapolated to infinity (AUCinf ) and maximum plasma concentration (Cmax ) geometric mean for encorafenib increased by 183% and 68.4%, respectively, when co-administered with posaconazole. Apparent encorafenib clearance decreased from 26.0 to 9.2 L/h when coadministered with posaconazole, and plasma terminal half-life (t½ ) of encorafenib increased from 4.3 to 7.3 h. The AUCinf and Cmax geometric mean for encorafenib increased by 83.0% and 44.7%, respectively, when co-administered with diltiazem. Similarly, the apparent encorafenib clearance decreased from 29.0 to 16.0 L/h when co-administered with diltiazem, and plasma t½ of encorafenib increased from 6.6 to 7.9 h. There were no deaths, serious adverse events (AEs), or patient discontinuations due to AEs in parts 1 or 2. The most frequently reported treatment-related AEs were erythema (n = 14; 88%) and headache (n = 11; 69%) in part 1 and headache (n = 7; 44%) in part 2. The results of this study indicate that co-administration of encorafenib with strong or moderate CYP3A4 inhibitors should be avoided.

Physiologically based pharmacokinetic modelling to predict drug-drug interactions for encorafenib. Part I. Model building, validation, and prospective predictions with enzyme inhibitors, inducers, and transporter inhibitors.

Encorafenib, a potent BRAF kinase inhibitor undergoes significant metabolism by CYP3A4 (83%) and CYP2C19 (16%) and also a substrate of P-glycoprotein (P-gp). Because of this, encorafenib possesses potential for enzyme-transporter related interactions. Clinically, its drug-drug interactions (DDIs) with CYP3A4 inhibitors (posaconazole, diltiazem) were reported and hence there is a necessity to study DDIs with multiple enzyme inhibitors, inducers, and P-gp inhibitors.USFDA recommended clinical CYP3A4, CYP2C19, P-gp inhibitors, CYP3A4 inducers were selected and prospective DDIs were simulated using physiologically based pharmacokinetic modelling (PBPK). Impact of dose (50 mg vs. 300 mg) and staggering of administrations (0-10 h) on the DDIs were predicted.PBPK models for encorafenib, perpetrators simulated PK parameters within twofold prediction error. Clinically reported DDIs with posaconazole and diltiazem were successfully predicted.CYP2C19 inhibitors did not result in significant DDI whereas strong CYP3A4 inhibitors resulted in DDI ratio up to 4.5. Combining CYP3A4, CYP2C19 inhibitors yielded DDI equivalent CYP3A4 alone. Strong CYP3A4 inducers yielded DDI ratio up to 0.3 and no impact of P-gp inhibitors on DDIs was observed. The DDIs were not impacted by dose and staggering of administration. Overall, this work indicated significance of PBPK modelling for evaluating clinical DDIs with enzymes, transporters and interplay.

Failure of diltiazem to prevent 1:1 conduction of atrial flutter: a case report.

BACKGROUND: Atrial flutter with 1:1 conduction to the ventricles is a dangerous cardiac arrhythmia. Contemporary guidelines recommend atrioventricular nodal blocking agents should be co-administered with class 1C anti-arrhythmics, as prophylaxis against 1:1 flutter. No guidance is provided on the type or strength of atrioventricular nodal blockade required, and in practice, these agents are frequently prescribed at low dose, or even omitted, due to their side effect profile. CASE PRESENTATION: A 62 year old Caucasian man with a history of paroxysmal atrial fibrillation treated with flecainide, presented with atrial flutter with 1:1 conduction to the ventricles and was cardioverted. Diltiazem was added to prevent this complication and he again presented with atrial flutter with 1:1 conduction to the ventricles, despite prophylaxis with coadministration of diltiazem. CONCLUSIONS: This case report demonstrates failure of diltiazem to prevent 1:1 flutter in a patient chronically treated with flecainide for paroxysmal atrial fibrillation.

Effect of Nicorandil, Diltiazem, or Isosorbide Mononitrate for Oral Antispastic Therapy After Coronary Artery Bypass Grafting Using Radial Artery Grafts-A Pilot Randomized Controlled Trial (ASRAB-Pilot): Rationale and Study Protocol.

INTRODUCTION: The current evidence for chronic oral antispastic medication use after coronary artery bypass grafting using radial artery grafts (RA-CABG) is controversial. Calcium channel blockers, such as diltiazem, are the most commonly used antispastic medications after RA-CABG; other options include nitrates and nicorandil, but to date no sufficiently powered randomized controlled trials have been conducted to compare their efficacy. METHODS: This is a single-center, open-label, parallel three-arm, pilot randomized controlled trial. Patients without contraindications to any study medications and who successfully underwent RA-CABG surgery will be consecutively screened. Eligible patients will be randomized in a ratio of 1:1:1 (a total of 150 patients, 50 per arm) to receive nicorandil 5 mg orally thrice daily, diltiazem 180 mg orally once daily, or isosorbide mononitrate 50 mg orally once daily for 24 weeks. The primary outcomes are RA graft failure at week 1 and week 24. The secondary outcomes include major adverse cardiovascular event (MACE, a composite of all-cause death, myocardial infarction, stroke, and unplanned revascularization) and angina recurrence. The safety outcomes include hypotension occurrence, withdrawal of renin angiotensin aldosterone system inhibitors, serious adverse events, and other concerned adverse events within 24 weeks. CONCLUSION: This pilot trial will compare the preliminary effects of nicorandil, diltiazem, and isosorbide mononitrate on angiographic and clinical outcomes in patients who have undergone RA-CABG. Recruitment began in June 2020, and the estimated primary completion date is early 2023. Results of this study will provide much needed information for design of large confirmatory trials on the effectiveness of oral antispastic medications after RA-CABG.