Amlodipine prevents adriamycin-induced toxicity in cultured rat mesangial cells by up-regulation of Smad6, Smad7 expression

Extensive studies have demonstrated that transforming growth factor-beta (TGF-β) plays an important role in the progression of renal diseases. A central component of TGF-β is the TGF-β family-specific Smad signal transduction pathway. TGF-β signals through Smad2, 4 to mediate renal fibrosis, whereas induction of Smad6, 7 inhibits renal fibrosis and inflammation. Amlodipine is the most frequently used antihypertensive drug among dihydropyridines. It is beneficial to the kidney and is widely used in treating kidney diseases. The aim of this study was to investigate effects of amlodipine on adriamycin-induced changes of lactate dehydrogenase (LDH) and expression of Smad6, 7 in rat mesangial cells. Results showed that amlodipine (10(-8) to 10(-5)mol/l) significantly decreased LDH activity in rat mesangial cells when given in combination with TGF-β₁ (P<0.01); amlodipine (10(-7), 10(-6)mol/l) significantly increased Smad6, 7 mRNA and protein expression in cells treated with adriamycin and TGF-β₁ (P<0.01). In conclusion, amlodipine protects against adriamycin-induced toxicity in rat mesangial cells by up-regulation of Smad6, 7 expressions.

Comparative study of high dose mono-therapy of amlodipine or telmisartan, and their low dose combination in mild to moderate hypertension

INTRODUCTION

Hypertension is one of the major public health challenges worldwide. Angiotensin receptor blockers (ARBs) and Calcium channel blockers (CCBs) are among the first line antihypertensive drugs. However, optimal treatment strategies in mild to moderate hypertensives who failed to achieve blood pressure (BP) control with low-dose mono-therapy are not well established. This study was done to compare efficacy and safety of high dose mono-therapy of Amlodipine, Telmisartan and their low dose combination in mild to moderate hypertensives who failed to achieve BP control with low dose mono-therapy of either drug.

MATERIALS AND METHODS

A total of 96 patients, fulfilling inclusion and exclusion criteria were enrolled in the study after obtaining informed consent. Patients were randomized into three treatment groups i.e. Telmisartan 80 mg, Amlodipine 10 mg and low dose combination of Telmisartan 40 mg +Amlodipine 5 mg once daily for two months. The systolic BP, Diastolic BP, and ADRs were recorded at 0, 2, 4, 8 weeks.

RESULTS

In the present study, significant reduction of mean systolic blood pressure (SBP) and mean diastolic blood pressure (DBP) was seen in all the three treatment groups. Low dose combination of Amlodipine 5 mg and Telmisartan 40 mg showed statistically significant reduction in SBP as compared to Telmisartan 80 mg mono-therapy and in DBP as compared to Amlodipine 10 mg mono-therapy. Maximum adverse drug reactions (ADRs) were reported in Amlodipine mono-therapy group, like ankle oedema, constipation, headache and fatigue.

DISCUSSION AND CONCLUSION

In term of BP control, low-dose combination therapy appears a better therapeutic approach than high-dose mono-therapy.

Impact of combined lipid lowering with blood pressure control on coronary plaque regression: rationale and design of MILLION study

A line of epidemiological studies suggests that the accumulation of coronary risk factors promotes the progression of coronary atherosclerosis. Recent clinical studies showed that aggressive low-density lipoprotein (LDL) cholesterol-lowering therapy using statins could regress coronary atheroma and reduce major cardiovascular events. Additionally, therapy that controlled amlodipine-based blood pressure reduced major cardiovascular events in patients with hypertension compared with an atenolol-based regimen. An open-label randomized multicenter study is primarily planned to evaluate the changes in coronary atheroma volume using intravascular ultrasonography 18-24 months after intensive lowering of LDL-cholesterol and blood pressure compared with a standard therapy indicated by current guidelines in Japanese patients with coronary artery disease (CAD). The secondary endpoints include changes in serum lipid levels, inflammatory markers, glucose markers and blood pressure. In total, 100 subjects with CAD who are undergoing percutaneous coronary intervention will be tested. The MILLION study will provide new evidence and therapeutic standards for the prevention of CAD in Japanese patients by controlling both LDL-C levels and blood pressure.

Amlodipine and cardiovascular outcomes in hypertensive patients: meta-analysis comparing amlodipine-based versus other antihypertensive therapy

BACKGROUND/AIMS

This meta-analysis compared the effects of amlodipine besylate, a charged dihydropyridine-type calcium channel blocker (CCB), with other non-CCB antihypertensive therapies regarding the cardiovascular outcome.

METHODS

Data from seven long-term outcome trials comparing the cardiovascular outcomes of an amlodipine-based regimen with other active regimens were pooled and analyzed.

RESULTS

The risk of myocardial infarction was significantly decreased with an amlodipine-based regimen compared with a non-CCB-based regimen (odds ratio [OR], 0.91; 95% confidence interval [CI], 0.84 to 0.99; p = 0.03). The risk of stroke was also significantly decreased (OR, 0.84; 95% CI, 0.79 to 0.90; p < 0.00001). The risk of heart failure increased slightly with marginal significance for an amlodipine-based regimen compared with a non-CCB-based regimen (OR, 1.14; 95% CI, 0.98 to 1.31; p = 0.08). However, when compared overall with β-blockers and diuretics, amlodipine showed a comparable risk. Amlodipine-based regimens demonstrated a 10% risk reduction in overall cardiovascular events (OR, 0.90; 95% CI, 0.82 to 0.99; p = 0.02) and total mortality (OR, 0.95; 95% CI, 0.91 to 0.99; p = 0.01).

CONCLUSIONS

Amlodipine reduced the risk of total cardiovascular events as well as all-cause mortality compared with non-CCB-based regimens, indicating its benefit for high-risk cardiac patients.

Comparative study between univariate spectrophotometry and multivariate calibration as analytical tools for quantitation of Benazepril alone and in combination with Amlodipine

Four simple, accurate, reproducible, and selective methods have been developed and subsequently validated for the determination of Benazepril (BENZ) alone and in combination with Amlodipine (AML) in pharmaceutical dosage form. The first method is pH induced difference spectrophotometry, where BENZ can be measured in presence of AML as it showed maximum absorption at 237nm and 241nm in 0.1N HCl and 0.1N NaOH, respectively, while AML has no wavelength shift in both solvents. The second method is the new Extended Ratio Subtraction Method (EXRSM) coupled to Ratio Subtraction Method (RSM) for determination of both drugs in commercial dosage form. The third and fourth methods are multivariate calibration which include Principal Component Regression (PCR) and Partial Least Squares (PLSs). A detailed validation of the methods was performed following the ICH guidelines and the standard curves were found to be linear in the range of 2-30μg/mL for BENZ in difference and extended ratio subtraction spectrophotometric method, and 5-30 for AML in EXRSM method, with well accepted mean correlation coefficient for each analyte. The intra-day and inter-day precision and accuracy results were well within the acceptable limits.

Rumpel-leede phenomenon in a hypertensive lady on amlodipine

We are describing a 60-year-old hypertensive lady who developed Rumpel-Leede phenomenon following the use of a tourniquet to obtain a blood sample. History revealed that she was on amlodipine therapy and that spontaneous sun-exposure related purpura was often seen since amlodipine was prescribed. Examinations and investigations provided normal results. She refused consent for a skin biopsy. Symptoms resolved after its substitution with enalapril and dihydrochlorothiazide, without any further recurrence.

Development and Validation of a LC-MS/MS Method for the Simultaneous Estimation of Amlodipine and Valsartan in Human Plasma: Application to a Bioequivalence Study

A reliable, simple, and robust liquid chromatography-tandem mass spectro-metric (LC-MS/MS) method has been developed and validated that employs solid-phase extraction for the simultaneous estimation of amlodipine and valsartan in human K₃EDTA plasma using amlodipine-d4 and valsartan-d9 as internal standards. Chromatographic separation of amlodipine and valsartan was achieved on the Luna C18 (2)100A (150 × 4.6 mm, 5 μm) column using acetonitrile: 5 mM ammonium formate solution (80:20, v/v) as the mobile phase at a flow rate of 0.8 mL/min in isocratic mode. Quantification was achieved using an electrospray ion interface operating in positive mode, under multiple reaction monitoring (MRM) conditions. The assay was found to be linear over the range of 0.302–20.725 ng/mL for amlodipine and 6.062–18060.792 ng/mL for valsartan. The method has shown good reproducibility, as intra- and interday precisions were within 10% and accuracies were within 8% of nominal values for both analytes. The method was successfully applied for the bioequivalence study of amlodipine and valsartan after oral administration of a fixed dose of the combination. Additionally, as required by the current regulatory bodies, incurred sample reanalysis was performed and found to be acceptable.

Different approaches in Partial Least Squares and Artificial Neural Network models applied for the analysis of a ternary mixture of Amlodipine, Valsartan and Hydrochlorothiazide

Different chemometric models were applied for the quantitative analysis of Amlodipine (AML), Valsartan (VAL) and Hydrochlorothiazide (HCT) in ternary mixture, namely, Partial Least Squares (PLS) as traditional chemometric model and Artificial Neural Networks (ANN) as advanced model. PLS and ANN were applied with and without variable selection procedure (Genetic Algorithm GA) and data compression procedure (Principal Component Analysis PCA). The chemometric methods applied are PLS-1, GA-PLS, ANN, GA-ANN and PCA-ANN. The methods were used for the quantitative analysis of the drugs in raw materials and pharmaceutical dosage form via handling the UV spectral data. A 3-factor 5-level experimental design was established resulting in 25 mixtures containing different ratios of the drugs. Fifteen mixtures were used as a calibration set and the other ten mixtures were used as validation set to validate the prediction ability of the suggested methods. The validity of the proposed methods was assessed using the standard addition technique.

"Permethrin chronic exposure alters motor coordination in rats: effect of calcium supplementation and amlodipine"

Recently was observed that pyrethroids decrease motor coordination and that calcium channels can be important targets for this effect. To contribute with this observation, this work studied the motor coordination and exploration (using hole-board apparatus), and locomotion (using open-field apparatus) of rats exposed to following treatments: permethrin (PM), PM plus calcium gluconate (CG) and PM plus amlodipine (AML). The results obtained show that CG or AML alone not changed the motor coordination while PM decreases it. CG kept the effect of permethrin; AML, however, decreased the values of permethrin to the control. Locomotor activity and exploration, which could confound results of motor coordination, were not modified by treatments. The concentration of PM in brain tissue was increased by the CG and AML. The neurosomatic index (weight brain/body weight) was increased by the PM and PM+CG. In conclusion, the combined results here obtained indicates that the calcium ion and the channels in which it is involved can be important targets for the toxic effect of pyrethroid insecticide permethrin on motor nerve activity of rats.

The role of cytochrome P450 2B6 and 2B4 substrate access channel residues predicted based on crystal structures of the amlodipine complexes

Recent X-ray crystal structures of human cytochrome P450 2B6 and rabbit cytochrome P450 2B4 in complex with amlodipine showed two bound ligand molecules, one in the active site and one in the substrate access channel. Based on the X-ray crystal structures, we investigated the interactions of P450 2B4 and 2B6 with amlodipine using absorbance spectroscopy, and determined the steady-state kinetics of 7-ethoxy-4-(trifluoromethyl)coumarin and 7-benzyloxyresorufin oxidation by some access channel mutants to evaluate the functional role of these residues in substrate turnover. The results of absorbance titrations are consistent with a simple mechanism with two parallel binding events that result in the formation of the enzyme complex with two molecules of amlodipine. Using this model we were able to resolve two separate ligand-binding events, which are characterized by two distinct KD values in each enzyme. The access channel mutants R73K in P450 2B6 and R73K, V216W, L219W, and F220W in P450 2B4 showed a significant decrease in kcat/KM with the both substrates. Overall, the results suggest that P450 2B4 and 2B6 form an enzyme complex with two molecules of amlodipine in solution, and R73, V216, L219 and F220 in P450 2B4 may play an important role in substrate metabolism.

A randomized, double-blind study to evaluate the efficacy and safety of a single-pill combination of telmisartan 80 mg/amlodipine 5 mg versus amlodipine 5 mg in hypertensive Asian patients

OBJECTIVE

To investigate the efficacy and safety of telmisartan 80 mg/amlodipine 5 mg (T80/A5) single-pill combination versus A5 in patients with essential hypertension not adequately controlled on A5 monotherapy.

METHODS

Asian patients ≥18 years old, with inadequately controlled blood pressure (BP) at enrolment, who failed to achieve a seated diastolic BP (DBP) goal (≥90 mmHg) following 6-weeks' open-label A5 treatment, were randomly allocated 1 : 1 to 8 weeks' double-blind treatment with T80/A5 single-pill combination or A5.

RESULTS

A total of 324 patients entered the double-blind treatment phase. The adjusted mean ± SE reduction in seated trough DBP from baseline to week 8 was significantly greater with T80/A5 (12.4 ± 1.0 mmHg) than A5 (10.2 ± 0.9 mmHg [primary endpoint, n = 314]). Results were similar in the subset of 262 Chinese patients. Treatment-related adverse events were 1.9% with T80/A5 and 2.4% with A5.

CONCLUSIONS

In Asian patients with hypertension, T80/A5 single-pill combination provided improved BP reduction after 8 weeks' treatment compared with A5 monotherapy. Both treatments were well tolerated.

Effect of single tablet of fixed-dose amlodipine and atorvastatin on blood pressure/lipid control, oxidative stress, and medication adherence in type 2 diabetic patients

BACKGROUND

Oxidized low-density lipoprotein (LDL) plays central roles in the formation and progression of atherosclerotic lesions. Malondialdehyde (MDA)-modified LDL (MDA-LDL) is speculated to be generated as a result of oxidative stress in the human body. Because both amlodipine and atorvastatin have been reported to reduce oxidative stress, it is expected that both drugs would have a favorable influence to reduce oxidative stress.

OBJECTIVE

The objective of this study was to investigate the effects of a single pill of amlodipine (5 mg)/atorvastatin (10 mg) on oxidative stress, blood pressure/lipid control and adherence to medication in patients with type 2 diabetes.

METHODS

This combination tablet was administered to 29 patients (16 male), and MDA-LDL, blood pressure, lipid profile, renal/liver function, CPK, hs-CRP, adiponectin, BNP, and HbA1c were measured at baseline, 6, and 12 months, and baPWV and mean IMT were measured at baseline and 12 months. Medication adherence was examined using a questionnaire at 6 months.

RESULTS

MDA-LDL was decreased significantly. LDL-C, TG, and Cr were significantly decreased at 6 and 12 months compared with baseline. eGFR was increased at 6 months, and urinary albumin/creatinine ratio was decreased at 12 months. BNP was decreased at 6 and 12 months, and adiponectin was increased at 12 months. Both mean IMT and baPWV were significantly decreased. The results of the questionnaire showed that 93% of patients were satisfied with this medication. No severe adverse event was observed.

CONCLUSION

This combination tablet controlled both hypertension and dyslipidemia well in type 2 diabetic patients. The deceases in mean IMT and baPWV might suggest the improvement of atherosclerosis by this medication, which could be caused by the reduction of oxidative stress measured by MDA-LDL. In addition, this medication is expected to improve medication adherence.

Evaluation of effectiveness and safety of amlodipine/valsartan/hydrochlorothiazide single-pill combination therapy in hypertensive patients: an observational study

Objective

This study evaluated the effectiveness and safety of amlodipine/valsartan/hydrochlorothiazide (A + V + H) single-pill combination therapy in the treatment of hypertensive patients in daily practice.

Design and methods

This prospective, open-label, observational study, enroled adults for whom their physician considered treatment with the single pill combination as indicated. The observational period per patient was ∼3 months. Results were evaluated using basic descriptive statistical methods.

Main outcome

Data of 7132 patients were analyzed. At baseline, the mean blood pressure (BP) was 158.8 ± 17.7 mmHg (systolic, sBP) and 91.5 ± 10.7 mmHg (diastolic, dBP). The most common cardiovascular risk factors were positive family history, dyslipidemia, and diabetes mellitus. The most commonly used daily doses of A + V + H at study end were 5/160/12.5 mg (30.5%) or 10/160/12.5 mg (33.1%). At the last visit mean BP was 135.0 ± 11.8 mmHg (sBP) and 80.2 ± 7.3 mmHg (dBP). The mean BP reduction at last visit compared with baseline was −23.7 ± 17.5 mmHg (sBP) and −11.3 ± 10.6 mmHg (dBP); 43.5% of the patients reached normalization (BP <140/90 mmHg for non-diabetics or <130/80 mmHg for diabetics) and 71.3% reached therapeutic response (sBP <140 or ≥20 mmHg decrease vs baseline and dBP <90 or ≥10 mmHg decrease vs baseline in non-diabetic patients and sBP <130 mmHg or ≥20 mmHg decrease vs baseline and dBP <80 mmHg or ≥10 mmHg decrease vs baseline in patients with diabetes). Adverse events (AEs) were recorded in 2.3% of the patients, the most frequent being peripheral edema (0.6%) and dizziness (0.2%).

Conclusions

In daily practice, A + V + H single-pill treatment effectively lowered the average BP in patients with essential hypertension and was well tolerated.

Is periodontal health a predictor of drug-induced gingival overgrowth? A cross-sectional study

BACKGROUND

Gingival overgrowth is a common side-effect of amlodipine regimen on the oral cavity. There is controversy regarding the cause and effect relationship of periodontal health and drug induced gingival overgrowth. Therefore, this study was conducted to investigate and to assess the relationship between the periodontal health and the onset and severity of gingival overgrowth in hypertensive patients receiving amlodipine.

MATERIALS AND METHODS

A total of 99 known hypertensive patients on amlodipine regimen were included in this study. Probing pocket depth (PPD) and clinical attachment loss (CAL) were noted on four sites of maxillary and mandibular anterior teeth. Gingival enlargement scores were assessed for each patient by employing the hyperplastic index. Oral hygiene status was evaluated using the calculus index (CI). Patients were divided into H, E and L groups based on their periodontal status and responders and non-responders based on their hyperplastic index scores. Differences in means of different periodontal variables in different groups were tested for significance by using ANOVA and unpaired Student t-test. Pearson's correlation coefficient was calculated to assess the correlation between different variables. For all analyses, P < 0.05 was considered to be significant.

RESULTS

All the periodontal parameters were statistically highly significant (P = 0.00) amongst H, E and L groups and between responders and non-responders. Statistically highly significant Pearson correlation coefficients were found between mean PPD and mean hyperplastic score, mean CAL and mean hyperplastic score and mean calculus and mean hyperplastic score.

CONCLUSION

The results of this study indicated a definite association between periodontal health and development and severity of amlodipine-induced gingival overgrowth.

Simultaneous determination of amlodipine, valsartan and hydrochlorothiazide by LC-ESI-MS/MS and its application to pharmacokinetics in rats

Polypill is a fixed-dose combination that contains three or more active ingredients used as a single daily pill to achieve a large effect in preventing cardiovascular disease with minimal adverse effects. A novel and accurate liquid chromatography tandem mass spectrometry method using electrospray ionization mode has been developed and validated for the simultaneous determination of amlodipine (AMD), valsartan (VAL) using losartan (LOS) as an internal standard (IS), and hydrochlorothiazide (HCT) using furosemide (FSD) as an IS. The separation was carried on Aquasil C₁₈ (50 mm×2.1 mm, 5 µm) reversed phase column using acetonitrile and water containing 0.1% formic acid (50:50, v/v) as the mobile phase. The method was validated in terms of linearity, accuracy and precision over the concentration range of 1–1000 ng/mL. The intra and inter-day precision and accuracy, stability and extraction recoveries of all the analytes were in the acceptable range. This method can be successfully applied to the pharmacokinetic study of AMD, VAL and HCT when given as a polypill.

[Edematous and painful leg. Pathophysiology in the spotlight: presentation of a case]

We report on a 74-year-old woman visually impaired and under treatment with amlodipine, valsartan and thyroid hormone. The patient complained of her unique, edematous and painful leg after a local trauma. The worsening was slow and gradual, affecting walk and state of mind. Several unsuccessful diagnoses were done before suspecting and confirming a Complex Regional Pain Syndrome. Edema disappeared dramatically after amlodipine empirical discontinuation. Pain improved gradually with rehabilitation exercises but, mainly, after gaining skills and self-esteem due to cataract surgery of her unique functional eye. It was necessary to decrease thyroid hormone dosage after a long lasting balance. The sympathetic nervous system role of the case is discussed.

Development and validation of an rp-hplc method for simultaneous determination of Ramipril and Amlodipine in tablets

An rp-hplc method for the simultaneous determination of Ramipril (RP) and Amlodipine (AL) in tablets was developed and validated by Chinese Pharmacopoeia 2010. The linearity of the proposed method was investigated in the range of 0.01–0.25 mg/mL (r²=0.9998) for RP and 0.014–0.36 mg/mL (r²=0.9997) for AL. The limits of detection (LOD) were 0.06 μg/mL and 0.02 μg/mL for RP and AL, and the limits of quantitation (LOQ) were 0.2 μg/mL and 0.07 μg/mL, respectively. Some major impurities and degradation products did not disturb the detection of RP and AL and the assay can thus be considered stability-indicating.

Shock due to amlodipine overdose

Amlodipine is a commonly prescribed calcium channel blocker. Its toxicity is the leading cause of drug overdose seen in the practice of cardiovascular medicine. It can lead to profound hypotension and shock. Management involves early and aggressive supportive measures and calcium infusion in large doses to overcome competitive blockade. We report one such case that presented with amlodipine overdose and was successfully managed.

Management of chronic hypertension during pregnancy with furosemide, amlodipine or aspirin: a pilot clinical trial

OBJECTIVE

To determine the maternal and neonatal efficacy and safety with furosemide, amlodipine or aspirin in women with mild/moderate chronic hypertension during pregnancy.

METHODS

A pilot clinical trial was performed in a tertiary teaching hospital in Panama. Pregnant patients with mild/moderate chronic hypertension at ≤20 weeks of gestation were invited to take part in the study. Mild/moderate chronic hypertension was defined as a pregnancy with systolic blood pressure of 140-159 mmHg or diastolic blood pressure of 90-109 mmHg. Women in the furosemide group received 20 mg of furosemide oral each day, those in the amlodipine group received 5 mg of amlodipine oral each day and those in the aspirin group received 75 mg of orally-administered acetylsalicylic acid each day.

RESULTS

We enrolled 63 patients during the study period, 21 women were randomised to each group (aspirin, amlodipine and furosemide). We found no difference in maternal complications, pre-term births, mean birth weight or in the proportion of small for gestational age infants among treatment groups. Severe hypertension and aggregate pre-eclampsia were similar among treatment groups.

CONCLUSION

This pilot trial demonstrates that both furosemide and amlodipine might have the same effect during pregnancy. However, a large clinical trial is necessary to prove this.

Efficacies of Controlling Morning Blood Pressure and Protecting the Kidneys by Treatment With Valsartan and Nifedipine CR or Valsartan and Amlodipine (MONICA Study)

Background

It is controversial whether a single-pill fixed-dose combination of angiotensin II type 1 receptor blocker and calcium channel blocker (CCB) is effective for all types of hypertension.

Methods

Thirty-five patients with uncontrolled blood pressure (BP) under treatment with valsartan 80 mg/day or amlodipine 5 mg/day were enrolled. They were randomly divided into two treatment groups: a single-pill fixed-dose combination of valsartan 80 mg/day and amlodipine 5 mg/day in the morning (VA group), or valsartan 80 mg/day in the morning and nifedipine CR 20 mg/day at night (VN group), and treated for 16 weeks. If the patient did not reach the target office BP at 8 weeks, they received double doses of CCBs.

Results

In the VN group, morning diastolic BP was significantly lower than the respective values in the VA group at 8 weeks. The percentage of patients who required a double dose of CCB in the VN group was significantly lower than that in the VA group. At 16 weeks, the BP levels in both groups were significantly reduced. Urinary albumin/creatinine at 16 weeks was significantly less than that at 0 weeks in the VN group.

Conclusion

Combination therapy with valsartan and nifedipine CR may help to control morning BP and protect the kidneys.

Study of interaction of tramadol with amlodipine in mice

Objective:

To study a possible interaction between tramadol, an opioid analgesic and amlodipine, a dihydropyridine calcium channel blocker with proposed antinociceptive property.

Materials and Methods:

Albino mice of Haffkine strain were used for the study. The experiment was carried out using tail-flick method. Different doses of tramadol (50 mg/kg, 22.8 mg/kg and 10 mg/kg) were administered intraperitoneally to select the nonanalgesic dose. The animals were treated with different doses of amlodipine (2.5 mg/kg, 3.0 mg/kg, 3.5 mg/kg) to study its antinociceptive action. Combination of different doses of both the drugs were administered to study antinociceptive effect of the combination.

Results:

Tramadol, showed dose dependent antinociception which persisted for entire two hours of the study period. Antinociceptive action was seen with amlodipine at a dose of 3.5 mg/kg. Different doses of amlodipine (2.5 mg/kg, 3.0 mg/kg) in combination with the nonanalgesic dose of tramadol (10 mg/kg) produced a significant enhancement of antinociceptive effect of tramadol. Combination of 3.5 mg/kg dose of amlodipine with nonanalgesic dose of tramadol (10 mg/kg) further enhances antinociceptive activity.

Conclusion:

It is concluded that combination of amlodipine, a N - type calcium channel blocker, with tramadol produce significant enhancement of antinociceptive activity of tramadol.

Comparative study between derivative spectrophotometry and multivariate calibration as analytical tools applied for the simultaneous quantitation of Amlodipine, Valsartan and Hydrochlorothiazide

Four simple, accurate and specific methods were developed and validated for the simultaneous estimation of Amlodipine (AML), Valsartan (VAL) and Hydrochlorothiazide (HCT) in commercial tablets. The derivative spectrophotometric methods include Derivative Ratio Zero Crossing (DRZC) and Double Divisor Ratio Spectra-Derivative Spectrophotometry (DDRS-DS) methods, while the multivariate calibrations used are Principal Component Regression (PCR) and Partial Least Squares (PLSs). The proposed methods were applied successfully in the determination of the drugs in laboratory-prepared mixtures and in commercial pharmaceutical preparations. The validity of the proposed methods was assessed using the standard addition technique. The linearity of the proposed methods is investigated in the range of 2-32, 4-44 and 2-20 μg/mL for AML, VAL and HCT, respectively.

Results from a 12 months, randomized, clinical trial comparing an olmesartan/amlodipine single pill combination to olmesartan and amlodipine monotherapies on blood pressure and inflammation

AIM

Hypertension affects nearly 1 in 3 adults in the United States, and it is an important modifiable risk factor for coronary artery disease, heart failure, renal failure, and stroke. The aim of this study was to evaluate the effects of a fixed-dose olmesartan/amlodipine combination on blood pressure control, lipid profile, insulin sensitivity, and inflammation compared to singles monotherapies.

METHODS

We randomized 276 hypertensive patients to olmesartan 20 mg, amlodipine 10mg or a single pill containing a fixed-dose olmesartan/amlodipine combination 20/5mg for 12 months. We evaluated: body weight, body mass index (BMI), systolic and diastolic blood pressure (SBP and DBP), fasting plasma glucose (FPG), fasting plasma insulin (FPI), lipid profile, omentin, chemerin, high sensitivity C-reactive protein (Hs-CRP). At baseline, and after 6 and 12 months, patients underwent an euglycemic, hyperinsulinemic clamp to assess insulin sensitivity (M value).

RESULTS

Olmesartan/amlodipine combination was more effective than amlodipine or olmesartan in reducing blood pressure. Olmesartan/amlodipine combination, but not amlodipine, decreased FPG after 12 months. Olmesartan/amlodipine combination better decreased FPI and HOMA index and increased M value compared to olmesartan and amlodipine monotherapies. Olmesartan/amlodipine significantly decreased chemerin and omentin compared to olmesartan and amlodipine.

CONCLUSION

Other than to be more effective in reducing blood pressure, olmesartan/amlodipine single pill combination gave also a major increase of insulin sensitivity and a decrease of inflammatory markers compared to single monotherapies.

The efficacy and safety of fixed-dose combination of amlodipine/benazepril in Chinese essential hypertensive patients not adequately controlled with benazepril monotherapy: a multicenter, randomized, double-blind, double-dummy, parallel-group clinical trial

This double-blind, double-dummy clinical trial evaluated the efficacy and safety of two strengths of fixed-dose combination of amlodipine/benazepril in Chinese hypertensive patients not adequately controlled with benazepril. Of 442 patients who received treatment with benazepril 10 mg for 4 weeks, 341 patients failed to achieve to diastolic blood pressure (DBP) <90 mmHg. These non-responders were randomized to receive amlodipine/benazepril 2.5/10 mg, or amlodipine/benazepril 5/10 mg, or benazepril 10 mg for 8 weeks. BP reductions with amodipinel/benazepril 2.5/10 mg (15.2/11.8 mmHg) or amlodipine/benazepril 5/10 mg (15.4/12.4 mmHg) were significantly greater than that with benazepril 10 mg (9.88/9.46 mmHg) at study end (p < 0.01, combination versus benazepril). BP control rate was 83.8% with amlodipine/benazepril 2.5/10 mg, 80.2% with amlodipine/benazepril 5/10 mg, 64.9% with benazepril 10 mg at study end (p < 0.01, combination versus benazepril). Three groups were generally well tolerated. Our study indicated that amlodipine/benazepril fixed-dose combination offered significant additional BP reductions and BP control rate compared with the continuation of benazepril monotherapy. No significant differences were observed in both BP reductions and BP control rate between amlodipine/benazepril 2.5/10 mg and amlodipine/benazepril 5/10 mg.

Simultaneous determination of losartan, losartan acid and amlodipine in human plasma by LC-MS/MS and its application to a human pharmacokinetic study

INTRODUCTION

A simple, rapid and sensitive liquid chromatography-tandem mass spectrometric assay method has been developed and fully validated for simultaneous quantification of losartan and its active metabolite, losartan carboxylic acid, and amlodipine in human plasma. Irbesartan was used as an internal standard.

MATERIALS AND METHODS

The analytes were extracted from human plasma samples by solid-phase extraction technique using Oasis HLB cartridges, (Waters Corporation, Mumbai, India). The reconstituted samples were chromatographed on a C18 column by using an 85:15, v/v mixture of methanol and 0.1% v/v formic acid as the mobile phase at a flow rate of 1.0 mL/min. A detailed validation of the method was performed as per the FDA guidelines.

RESULTS

The calibration curves obtained were linear (r ≥ 0.99) over the concentration range of 0.5-1000 ng/mL for losartan and for its active metabolite losartan acid and 0.05-10.1 ng/mL for amlodipine. The results of the intra- and inter-day precision and accuracy studies were well within the acceptable limits.

CONCLUSIONS

A run time of 2.5 min for each sample made it possible to analyze more than 300 plasma samples per day. The proposed method was found to be applicable to clinical studies.