Candesartan cilexetil: an angiotensin II-receptor blocker

Candesartan Protects Against Cadmium-Induced Hepatorenal Syndrome by Affecting Nrf2, NF-κB, Bax/Bcl-2/Cyt-C, and Ang II/Ang 1-7 Signals

Cadmium (Cd) is a serious pollutant in the environment. Candesartan is an angiotensin II (Ang II) receptor antagonist with promising diverse health benefits. The current study is planned to investigate the hepatorenal protective effects of candesartan against Cd-induced hepatic and renal intoxication. Our results demonstrated that candesartan effectively attenuated Cd-induced hepatorenal intoxication, as evidenced by improving hepatic and renal function biomarkers. Besides, candesartan reversed hepatic and renal histopathological abrasions induced by Cd toxicity. Candesartan antioxidant effect was mediated by Nrf2 activation. Also, candesartan suppressed hepatorenal inflammation by modulating NF-κB/IκB. Moreover, candesartan attenuated Cd hepatorenal apoptosis by upregulating Bcl-2 and downregulating Bax and Cyt-C proteins. Interestingly, these effects are suggested to be an outcome of modulating of Ang II/Ang 1-7 signal. Overall, our findings revealed that candesartan could attenuate Cd-induced hepatorenal intoxication through modulation of Nrf2, NF-κB/IκB, Bax/Bcl-2/Cyt-c, and Ang II/Ang 1-7 signaling pathways.

Major implications of single nucleotide polymorphisms in human carboxylesterase 1 on substrate bioavailability

The number of studies and reviews conducted for the Carboxylesterase gene is limited in comparison with other enzymes. Carboxylesterase (CES) gene or human carboxylesterases (hCES) is a multigene protein belonging to the α/β-hydrolase family. Over the last decade, two major carboxylesterases (CES1 and CES2), located at 16q13-q22.1 on human chromosome 16 have been extensively studied as important mediators in the metabolism of a wide range of substrates. hCES1 is the most widely expressed enzyme in humans, and it is found in the liver. In this review, details regarding CES1 substrates include both inducers (e.g. Rifampicin) and inhibitors (e.g. Enalapril, Diltiazem, Simvastatin) and different types of hCES1 polymorphisms (nsSNPs) such as rs2244613 and rs71647871. along with their effects on various CES1 substrates were documented. Few instances where the presence of nsSNPs exerted a positive influence on certain substrates which are hydrolyzed via hCES1, such as anti-platelets like Clopidogrel when co-administered with other medications such as angiotensin-converting enzyme (ACE) inhibitors were also recorded. Remdesivir, an ester prodrug is widely used for the treatment of COVID-19, being a CES substrate, it is a potent inhibitor of CES2 and is hydrolyzed via CES1. The details provided in this review could give a clear-cut idea or information that could be used for further studies regarding the safety and efficacy of CES1 substrate.

Repurposing Candesartan Cilexetil as Antibacterial Agent for MRSA Infection

Staphylococcus aureus is an important pathogen causing hospital-acquired infections. Methicillin-resistant S. aureus (MRSA), biofilms, and persisters are highly tolerant to traditional antibiotics and make it difficult to treat. Therefore, new antimicrobial agents are urgently needed to treat hard-to-eradicate diseases caused by this bacterium. In this study, candesartan cilexetil (CC), an angiotensin hypertension drug, had strong antimicrobial activity against S. aureus with minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of 8-16 μg/ml and 16-32 μg/ml. CC exhibited limited cytotoxicity and low potential to induce drug resistance. In addition, it showed a synergistic antibacterial effect when combined with gentamicin and tobramycin. The effective concentrations to inhibit MRSA biofilm formation were 16-64 μg/ml, and intractable persisters were killed at 4-8 × MIC. Through the analysis of its mechanism of action, it was evident that the membrane permeability was disrupted as well as the cell structure was damaged. Furthermore, we demonstrated that CC had antibacterial effects in vivo in MRSA-infected murine skin abscess models. In conclusion, these results imply that CC might be a potential antibacterial agent for the treatment of S. aureus-associated infections.

Environmental Risk Assessment of Active Human Pharmaceutical Ingredients in Urban Rivers in Japan

Active pharmaceutical ingredients (APIs) have become a public concern owing to their possible adverse effects on aquatic organisms. Ministry of Health, Labor and Welfare in Japan (MHLW) issued "Guidance on the Environmental Risk Assessment (ERA) in new pharmaceutical development" in 2016. To evaluate the validity of phase 1 in the MHLW's ERA guidance, we monitored the measured environmental concentrations (MECs) of approved APIs in urban rivers and sewage treatment plants (STPs) in Japan and compared these MECs with the predicted environmental concentration (PEC). We collected water samples from urban seven rivers and three STPs during each season. Fifty-one APIs for human and veterinary use and the artificial sweetener sucralose were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Forty-four APIs were observed in the rivers and 42 were found in the influent and effluent of STPs, with levels ranging from nanograms to micrograms per liter. The action limit in phase I of the MHLW's guidance was set to 10 ng/L, and there was no API except for ketoprofen, for which PEC of the MHLW's guidance (PECjapan) was lower than 10 ng/L and the maximum MEC (MECmax) was 10 ng/L or greater. Almost all APIs also had median MECs that were lower than those of the respective PECjapan. These results indicate that the PECjapan values in phase I of the MHLW's guidance were appropriate. However, some APIs had MECmax values that were greater than those of the respective PECjapan due to overestimation of the dilution factor of river water and/or underestimation of API production.

Development of a High-throughput NanoBRET Screening Platform to Identify Modulators of the RAS/RAF Interaction

Activating mutations in RAS are found in approximately 30% of human cancers, resulting in the delivery of a persistent signal to critical downstream effectors that drive tumorigenesis. RAS-driven malignancies respond poorly to conventional cancer treatments and inhibitors that target RAS directly are limited; therefore, the identification of new strategies and/or drugs to disrupt RAS signaling in tumor cells remains a pressing therapeutic need. Taking advantage of the live-cell bioluminescence resonance energy transfer (BRET) methodology, we describe the development of a NanoBRET screening platform to identify compounds that modulate binding between activated KRAS and the CRAF kinase, an essential effector of RAS that initiates ERK cascade signaling. Using this strategy, libraries containing synthetic compounds, targeted inhibitors, purified natural products, and natural product extracts were evaluated. These efforts resulted in the identification of compounds that inhibit RAS/RAF binding and in turn suppress RAS-driven ERK activation, but also compounds that have the deleterious effect of enhancing the interaction to upregulate pathway signaling. Among the inhibitor hits identified, the majority were compounds derived from natural products, including ones reported to alter KRAS nanoclustering (ophiobolin A), to impact RAF function (HSP90 inhibitors and ROS inducers) as well as some with unknown targets and activities. These findings demonstrate the potential for this screening platform in natural product drug discovery and in the development of new therapeutic agents to target dysregulated RAS signaling in human disease states such as cancer.

Candesartan and valsartan Zn(ii) complexes as inducing agents of reductive stress: mitochondrial dysfunction and apoptosis

Candesartan and valsartan Zn(ii) complexes as inducing agents of reductive stress, including mitochondrial dysfunction and apoptosis.

Pharmacokinetics and bioequivalence of fixed-dose combination of candesartan cilexetil/amlodipine besylate (16/10 mg) versus coadministration of individual formulations in healthy subjects

This study compared the pharmacokinetics of a fixed-dose combination (FDC) of candesartan (16 mg) and amlodipine (10 mg) versus coadministration of individual formulations to clarify the bioequivalence of the FDC. In this randomized, open-label, single-dose, 2-treatment, 2-way crossover study, healthy Korean volunteers received a single dose of candesartan (16 mg) with amlodipine (10 mg) as either an FDC or single agents concomitantly administered, with a 2-week washout period. Serial blood samples were collected up to 72 hours after dosing for each treatment period, and plasma concentrations of candesartan and amlodipine were measured using a validated liquid chromatography-tandem mass spectrometry method. A total of 39 subjects completed the study. The geometric mean ratios (GMRs) and 90% confidence intervals (CIs) for the area under the plasma concentration-time curve from time 0 to the last measurement (AUC_0-t) and the peak plasma concentration (C_max) for candesartan were 1.0182 (0.9562–1.0841) and 0.9492 (0.8726–1.0324), respectively. The GMR and 90% CI for the AUC_0-t and C_max for amlodipine were 1.0552 (1.0255–1.0857) and 1.0668 (1.0259–1.1094), respectively. In conclusion, the new FDC formulation of candesartan (16 mg) and amlodipine (10 mg) was bioequivalent to the concomitant administration of single agents. A single dose of candesartan/amlodipine as the FDC or as single agents was well tolerated.

Hypertension and Headache: the Effect of Antihypertensive Drugs

Headache is considered to be one of the main symptoms of arterial hypertension (HT). Complaints of headache are presented by many patients with HT: from 44% to 87%. It is obvious that the majority of complaints of headache in patients with HT is not due to headaches due to increased blood pressure (BP), but multimorbidity (polymorbidity) – the presence of coexisting primary headaches, most often, as in the population as a whole, chronic tension headache (57-85%) and migraine (15-30%). On the other hand, the frequency of HT in patients with migraine ranges from 32% to 44%. The relationship between migraine and HT may be due to common exogenous (external) and endogenous (genetic) factors, as well as common pathophysiological mechanisms. External risk factors, which can be associated with both migraine and HT, include the nature of the diet (excessive consumption of table salt with food), low physical activity, chronic stress; both diseases are also associated with the presence of a connection with the metabolic syndrome. The role of hyperactivation of the renin-angiotensin-aldosterone and adrenergic system and endothelial dysfunction are actively discussed. Angiotensin-converting enzyme takes an active part in the BP control and vascular tone; it is known that some angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB) have demonstrated efficacy in preventing migraine attacks. The presence of HT can contribute to the chronic course of primary headache, and effective treatment of HT with antihypertensive drugs, on the contrary, can have a positive effect on the course of primary headaches. Antihypertensive drugs reduce the frequency of headaches compared to placebo, but heterogeneity between different classes was revealed. There was a statistically significant decrease in the frequency of headaches compared to placebo during treatment with beta-blockers, ACEI, ARB, diuretics, while calcium antagonists did not reduce the frequency of headaches. According to a number of studies, the frequency of headaches during the treatment with ARB (candesartan) is comparable to that in the placebo group. Some antihypertensive drugs are used to prevent migraine attacks.

Candesartan abrogates G protein-coupled receptors agonist-induced MAPK activation and cardiac myocyte hypertrophy

The renin-angiotensin-aldosterone system (RAAS) has been identified as a major contributor to the development of cardiac hypertrophy and the subsequent transition to heart failure. G protein-coupled receptors agonists such as angiotensin II (Ang II), endothelin-1 (ET-1) and phenylephrine (PE) have been implicated in hypertrophic responses in ventricular myocytes through the activation of several families of MAP kinases. In this study we examined the effect of candesartan, an Ang II type 1-(AT1)-receptor antagonist, on cardiac hypertrophy by using cultured neonatal rat cardiomyocytes. Stimulation with Ang II (100 nM), ET-1 (100 nM) or PE (1 µM) induced marked increases in [3H]Leucine incorporation (≥ 50%), compatible with enhanced protein synthesis. The addition of candesartan abrogated the increase in [3H]Leucine incorporation in response not only to Ang II but also to ET-1 and PE. To elucidate the mechanisms involved in this antihypertrophic effect of candesartan, we studied the activation of p38-MAPK, extracellular signal-regulated kinases (ERK1/2) and stress-activated protein kinases (SAPKs). Ang II, ET-1 and PE increased the phosphorylation levels of ERK1/2, p54 SAPK and p46SAPK and p38 in a time-dependent manner. This activation was completely blocked in the case of Ang II by pretreatment with candesartan. ET-1-induced activation of ERKs, SAPKs and p38 was also partially, but significantly, reduced by candesartan. PE-induced activation of SAPKs, but not ERKs and p38, was also reduced by candesartan. These results suggest that the hypertrophic response to ET-1 and PE, along with Ang II, is dependent upon a functioning AT1-receptor and may be mediated by AT 1 activation of the MAP kinases.

Angiotensin II Type 1 Receptor-Dependent GLP-1 and PYY Secretion in Mice and Humans

Angiotensin II (Ang II) is the key hormone mediator of the renin angiotensin system, which regulates blood pressure and fluid and electrolyte balance in the body. Here we report that in the colonic epithelium, the Ang II type 1 receptor is highly and exclusively expressed in enteroendocrine L cells, which produce the gut hormones glucagon-like peptide-1 and peptide YY (PYY). Ang II stimulated glucagon-like peptide-1 and PYY release from primary cultures of mouse and human colon, which was antagonized by the specific Ang II type 1 receptor blocker candesartan. Ang II raised intracellular calcium levels in L cells in primary cultures, recorded by live-cell imaging of L cells specifically expressing the fluorescent calcium sensor GCaMP3. In Ussing chamber recordings, Ang II reduced short circuit currents in mouse distal colon preparations, which was antagonized by candesartan or a specific neuropeptide Y1 receptor inhibitor but insensitive to amiloride. We conclude that Ang II stimulates PYY secretion, in turn inhibiting epithelial anion fluxes, thereby reducing net fluid secretion into the colonic lumen. Our findings highlight an important role of colonic L cells in whole-body fluid homeostasis by controlling water loss through the intestine.

Angiotensin II reduces food intake by altering orexigenic neuropeptide expression in the mouse hypothalamus

Angiotensin II (Ang II), which is elevated in many chronic disease states such as end-stage renal disease and congestive heart failure, induces cachexia and skeletal muscle wasting by increasing muscle protein breakdown and reducing food intake. Neurohormonal mechanisms that mediate Ang II-induced appetite suppression are unknown. Consequently, we examined the effect of Ang II on expression of genes regulating appetite. Systemic Ang II (1 μg/kg · min) infusion in FVB mice rapidly reduced hypothalamic expression of neuropeptide Y (Npy) and orexin and decreased food intake at 6 h compared with sham-infused controls but did not change peripheral leptin, ghrelin, adiponectin, glucagon-like peptide, peptide YY, or cholecystokinin levels. These effects were completely blocked by the Ang II type I receptor antagonist candesartan or deletion of Ang II type 1a receptor. Ang II markedly reduced phosphorylation of AMP-activated protein kinase (AMPK), an enzyme that is known to regulate Npy expression. Intracerebroventricular Ang II infusion (50 ng/kg · min) caused a reduction of food intake, and Ang II dose dependently reduced Npy and orexin expression in the hypothalamus cultured ex vivo. The reduction of Npy and orexin in hypothalamic cultures was completely prevented by candesartan or the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleoside. Thus, Ang II type 1a receptor-dependent Ang II signaling reduces food intake by suppressing the hypothalamic expression of Npy and orexin, likely via AMPK dephosphorylation. These findings have major implications for understanding mechanisms of cachexia in chronic disease states such as congestive heart failure and end-stage renal disease, in which the renin-angiotensin system is activated.

Cis-dichlorodiammineplatinum upregulates angiotensin II type 1 receptors through reactive oxygen species generation and enhances VEGF production in bladder cancer

We previously reported that angiotensin II type 1 receptor (AT1R) antagonists enhanced the cytotoxity of cis-dichlorodiammineplatinum (CDDP) in a bladder cancer xenograft model. To elucidate the synergistic mechanism, we investigated whether reactive oxygen species (ROS) generation induced by CDDP may affect the regulation of AT1R expression. Five invasive human bladder cancer cell lines, T24, UMUC-3, 5637, KU-1, and KU-19-19, were used in the in vitro study. For the in vivo study, T24 cells were used. We also examined AT1R and vascular endothelial growth factor (VEGF) expression in human bladder cancer specimens that had been treated with CDDP-based chemotherapy. The in vitro study showed that AT1R expression was significantly upregulated by CDDP in T24, KU-1, and KU-19-19 cells. On the other hand, AT1R expression was not changed in UMUC-3 and 5637 cells. ROS generation was also significantly upregulated by CDDP in T24, KU-1, and KU-19-19 cells. The upregulation of AT1R expression induced by CDDP was significantly suppressed by scavenging free radicals. Angiotensin II induced VEGF production in CDDP-treated cells; however, the AT1R antagonist significantly inhibited the increase in VEGF. The in vivo study results also showed that CDDP treatment upregulated AT1R expression, resulting in increased VEGF. Clinical specimens from patients who underwent cystectomy after neoadjuvant CDDP-based chemotherapy showed significantly higher AT1R and VEGF expression than corresponding transurethral resection specimens. Our findings indicate that CDDP upregulates AT1R expression though ROS generation and enhances VEGF production. Therefore, AT1R blockade may be an effective strategy for bladder cancer in combination with CDDP-based chemotherapy.

Telmisartan inhibits human urological cancer cell growth through early apoptosis

Angiotensin II receptor blockers (ARBs) are widely used as hypertensive therapeutic agents. In addition, studies have provided evidence that ARBs have the potential to inhibit the growth of several types of cancer cells. It was reported that telmisartan (a type of ARB) has peroxisome proliferator-activated receptor (PPAR)-γ activation activity. We previously reported that the PPAR-γ ligand induces growth arrest in human urological cancer cells through apoptosis. In this study, we evaluated the effects of telmisartan and other ARBs on cell proliferation in renal cell carcinoma (RCC), bladder cancer (BC), prostate cancer (PC) and testicular cancer (TC) cell lines. The inhibitory effects of telmisartan and other ARBs (candesartan, valsartan, irbesartan and losartan) on the growth of the RCC, BC, PC and TC cell lines was investigated using an MTT assay. Flow cytometry and Hoechst staining were used to determine whether the ARBs induced apoptosis. Telmisartan caused marked growth inhibition in the urological cancer cells in a dose- and time-dependent manner. Urological cancer cells treated with 100 μM telmisartan underwent early apoptosis and DNA fragmentation. However, the other ARBs had no effect on cell proliferation in any of the urological cancer cell lines. Telmisartan may mediate potent anti-proliferative effects in urological cancer cells through PPAR-γ. Thus, telmisartan is a potent target for the prevention and treatment of human urological cancer.

Angiotensin II type 1 receptor antagonist candesartan as an angiogenic inhibitor in a xenograft model of bladder cancer

PURPOSE

There have been several studies on the antitumor activity of angiotensin II type 1 receptor (AT1R) antagonists. In this study, we evaluated the efficacy of the AT1R antagonist candesartan in bladder cancer.

EXPERIMENTAL DESIGN

For the study in vitro, human bladder cancer cells (KU-19-19) were cultured with or without angiotensin II and candesartan. Various cytokines and cell viability were analyzed. For the study in vivo, a tumor xenograft model was prepared in nude mice using KU-19-19 cells. Mice were given candesartan daily by oral gavage. Microvessel density, expression of vascular endothelial growth factor (VEGF), and apoptosis were assessed.

RESULTS

Candesartan did not induce direct toxicity in KU-19-19 cells, but VEGF and interleukin-8 were significantly lower in candesartan-treated cells (2.55 +/- 0.25 and 6.58 +/- 0.48 pg/10(3) cells) than in the angiotensin II-treated control cells (3.16 +/- 0.42 and 7.91 +/- 0.69 pg/10(3) cells). In mice, candesartan both at doses of 2 and 10 mg/kg/d significantly suppressed tumor growth in mice (35.4% and 33.5% reduction in tumor volume). Microvessel density was significantly decreased by candesartan (9.8 +/- 2.8 per field) compared with the control group (17.6 +/- 6.0 per field), and VEGF expression was significantly suppressed by this AT1R antagonist. However, candesartan did not induce apoptosis of cancer cells in the tumor.

CONCLUSIONS

Specific blockade of AT1R prevented bladder tumor growth by inhibiting angiogenesis. However, its antitumor effect was not due to direct toxicity. Because AT1R antagonists are widely used to treat hypertension, and a 2 mg/kg/d dose level of candesartan is clinically achievable, this AT1R antagonist could also be used to treat bladder cancer.

Serum concentration of potassium in chronic heart failure patients administered spironolactone plus furosemide and either enalapril maleate, losartan potassium or candesartan cilexetil

OBJECTIVE

To retrospectively investigate elevation of serum potassium when spironolactone (25 or 50 mg/day) and furosemide were administered concomitantly with an angiotensin II converting enzyme inhibitor (ACE-I) or angiotensin II receptor blocker (ARB) to patients with chronic heart failure for 12 months and occurrence of hyperkalemia and hypokalemia because of concomitant administration of spironolactone plus an ACE-I or ARB and furosemide.

METHODS

Patients with chronic heart failure, who visited departments of cardiovascular internal medicine and cardiovascular surgery at the National Hospital Organization Osaka Medical Center, were enrolled for this study. Serum potassium, blood urea nitrogen (BUN), serum creatinine, uric acid, and serum sodium were determined in every patient at the time of start of treatment and at 3 and 12 months of treatment. Data from patients in Groups A (25 mg/day spironolactone + 40 mg/day furosemide + an ACE-I or ARB) and B (50 mg/day spironolactone + 40 mg/day furosemide + an ACE-I or ARB) were analysed for differences with respect to the ACE-I and ARB used.

RESULTS

When 50 mg/day spironolactone plus 5 mg/day enalapril maleate (enalapril) or 50 mg/day losartan potassium (losartan) or 8 mg/day candesartan cilexetil (candesartan) plus 40 mg/day furosemide were concomitantly used, the mean value of serum potassium was significantly elevated only in the group treated with 50 mg/day spironolactone regardless of the concomitant drug. The number of patients with hyperkalemia (>5.5 mEq/L) at 12 months of treatment was 12 (8.8%), while the number of patients with hypokalemia (<or=3.5 mEq/L) was 7 (5.1%). However, the occurrence of hyperkalemia was almost the same regardless of the dose of spironolactone or the ACE-I or ARB concomitantly administered. Therefore, if enalapril, losartan, or candesartan is concomitantly used, it is necessary to monitor the serum concentration of potassium, even if spironolactone is administered at a dose of 25 mg/day.

CONCLUSION

The occurrence of hyperkalemia in patients administered spironolactone is influenced by the dose, but when it is used concomitantly with enalapril, losartan or candesartan, the occurrence of hyperkalemia exceeding 5.5 mEq/L may increase even if the dose of spironolactone is as low as 25 mg. Thus it is essential to always monitor serum potassium.

Patterns of antihypertensive therapy in new users of angiotensin II-receptor blockers

PURPOSE

The patterns of angiotensin II-receptor blocker (ARB) therapy in patients with and without a history of antihypertensive use were studied.

METHODS

Data for this retrospective cohort study were obtained from Caremark's data warehouse. Patients were included in the analysis if they filled prescriptions for ARBs only, did not receive ARB therapy within the 6 months before the filling of the first ARB prescription (index date), were continuously eligible for benefits for 6 months before the index date, were eligible for prescription benefits for the 12 months following the index date, and were age 20-80 years.

RESULTS

Of the 174,573 patients sampled, 53.4% were new to all antihypertensive therapies. Of the patients receiving an ARB, 67.9% received another antihypertensive during the evaluation period. Over 40% of patients new to all antihypertensive therapies had no other antihypertensive added to their ARB regimen. Of the patients with a history of antihypertensive use, 22.3% discontinued all antihypertensives before starting therapy with an ARB. Patients starting therapy with losartan and valsartan were less likely to be treated with mono-therapy and more likely to be treated with ARB-diuretic therapy than were patients starting therapy with telmisartan, irbesartan, or candesartan.

CONCLUSION

Patients who started antihypertensive therapy with ARBs tended to be new to antihypertensive therapy and, in a plurality of cases, continued to receive therapy with ARBs only. More than a fifth of patients who received antihypertensive therapy in the recent past were switched from that therapy to treatment with ARBs only. Treatment patterns differed by initial ARB used and the demographic profile of the patient.

Drug interactions with angiotensin receptor blockers: a comparison with other antihypertensives

The ever-increasing introduction of new therapeutic agents means that the potential for drug interactions is likely to escalate. Numerous different classes of drugs are currently used to treat hypertension. The angiotensin receptor blockers offer one of the newest approaches to the management of patients with high blood pressure. Compared with other classes of antihypertensive agents, the angiotensin receptor blockers appear overall to have a low potential for drug interactions, but variations within the class have been detected. Losartan and irbesartan have a greater affinity for cytochrome p450 (CYP) isoenzymes and, thus, are more likely to be implicated in drug interactions. There is pharmacokinetic evidence to suggest that such interactions could have a clinical impact. Candesartan cilexetil, valsartan and eprosartan have variable but generally modest affinity and telmisartan has no affinity for any of the CYP isoenzymes. In vitro studies and pharmacokinetic/pharmacodynamic evaluation can provide evidence for some interactions, but only a relatively small number of drug combinations are usually studied in this way. The absence of any pharmacokinetic evidence of drug interaction, however, should not lead to complacency. Patients should be made aware of possible interactions, especially involving the concurrent use of over-the-counter products, and it may be prudent for all patients receiving antihypertensive treatment to be monitored for possible drug interactions at their regular check-ups. The physician can help by prescribing agents with a low potential for interaction, such as angiotensin receptor blockers.

Angiotensin II receptor blockers for the treatment of hypertension

The rising incidence of stroke, congestive heart failure (CHF) and end stage renal disease (ESRD) has signalled a need to increase awareness, treatment and control of hypertension. There continues to be a need for effective antihypertensive medications since hypertension is a major precursor to various forms of cardiovascular disease. The renin-angiotensin (AT) aldosterone system (RAAS) is a key component to the development of hypertension and can be one target of drug therapy. Angotensin II (ATII) receptor blockers (ARBs) are the most recent class of agents available to treat hypertension, which work by by inhibiting ATII at the receptor level. Currently, national consensus guidelines recommend that ARBs should be reserved for hypertensive patients who cannot tolerate angiotensin converting enzyme (ACE) inhibitors (ACEIs). ARBs, however, are moving to the forefront of therapy with a promising role in the area of renoprotection and CHF. Recent trials such as the The Renoprotective Effect of the Angiotensin-Receptor Antagonist Irbesartan in Patients with Nephropathy Due to Type 2 Diabetes Trial (IDNT), the Effect of Irbesartan on the Development of Diabetic Nephropathy in Patients with Type 2 Diabetes (IRMA2), and The Effects of Losartan on Renal and Cardiovascular Outcomes in Patients with Type 2 Diabetes and Nephropathy (RENAAL) study have demonstrated the renoprotective effects of ARBs in patients with Type 2 diabetes. The Valsartan Heart Failure Trial (Val-HeFT) adds to the growing body of evidence that ARBs may improve morbidity and mortality in CHF patients. As a class, ARBs are well tolerated and have a lower incidence of cough and angioedema compared to ACEIs. This article reviews the differences among the ARBs, existing efficacy data in hypertension, and explores the role of ARBs in CHF and renal disease.