Calcium-channel blockade (nitrendipine) in combination with ACE inhibition (captopril) in the treatment of mild to moderate hypertension

Angiotensin axis antagonists increase the incidence of haemodynamic instability in dihydropyridine calcium channel blocker poisoning

CONTEXT

Amlodipine, a dihydropyridine calcium channel blocker (CCB), is the leading cause of cardiovascular drug-related overdose deaths in the USA. In contrast, angiotensin-II receptor blockers (ARBs) and angiotensin converting enzyme inhibitors (ACEIs) cause minimal toxicity in overdose. ACEIs/ARBs are often combined with dihydropyridines in hypertension treatment. Co-ingested ARBs/ACEIs may significantly contribute to the toxicity of dihydropyridine, but this has not been investigated.

OBJECTIVE

To investigate the clinical outcomes from dihydropyridine overdoses with ARBs/ACEIs versus dihydropyridine overdoses alone.

METHODS

This was a retrospective study of patients reported to the New South Wales Poisons Information Centre (NSW PIC) and 3 toxicology units (Jan 2016 to Jun 2019) in Australia. Patients >14 years who took an overdose of dihydropyridines (amlodipine, felodipine, lercanidipine, nifedipine) were included. Concurrent overdoses with non-dihydropyridine CCBs, alpha-blockers and beta-blockers were excluded. Patient demographics, drugs exposure details, serial vital signs, treatments and outcome were collected.

RESULTS

There were 100 patients. 68 took mixed overdoses of dihydropyridines with ARBs/ACEIs and 32 took single overdoses of dihydropyridines without ARBs/ACEIs. The mixed group had lower median nadir mean arterial pressures (62 vs 75 mmHg, p < 0.001), more frequently had hypotension (OR 4.5, 95%CI: 1.7-11.9) or bradycardia (OR 8.8, 95%CI: 1.1-70). Multivariable analysis indicated the mixed overdoses had an 11.5 mmHg (95%CI: 4.9-18.1) lower minimum systolic blood pressure (SBP) compared with the single group; other factors associated with a lower minimum SBP were higher doses [2.3 mmHg (95%CI: 1.1-3.5) lower per 10 defined daily doses] and younger age [2.2 mmHg (95%CI: 0.3-4.2) higher per decade]. A larger proportion of the mixed ingestion group received intravenous fluids (OR 5.7, 95%CI: 1.8-18.6) and antidotes and/or vasopressors (OR 2.9, 95%CI: 1.004-8.6).

CONCLUSION

Combined overdoses of dihydropyridines with ARBs/ACEIs caused more significant hypotension and required more haemodynamic support than overdoses of dihydropyridines alone.

Synergism of irbesartan and amlodipine on hemodynamic amelioration and organ protection in spontaneously hypertensive rats

AIM

To investigate the synergism of low-doses of amlodipine and irbesartan on reduction of blood pressure variability (BPV), amelioration of baroreflex sensitivity (BRS) and organ protection in spontaneously hypertensive rats (SHR).

METHODS

The rats were administered amlodipine (1 mg·kg(-1)·d(-1)) alone, irbesartan (10 mg·kg(-1)·d(-1)) alone, or the combination of the two drugs for 4 months. The drugs were mixed into the rat chow. Blood pressure (BP) was continuously monitored in conscious animals. After the determination of BRS, the rats were killed for morphological evaluation of organ damages.

RESULTS

The combination of low-dose irbesartan and amlodipine had statistically significant synergism on reduction of BP and BPV, amelioration of BRS and organ protection in SHR. Multiple regression analysis showed that the decrease in left ventricular hypertrophy was associated with the decrease in systolic BPV (r=0.665, P<0.01); the decrease in aortic hypertrophy was associated with the increase in BRS (r=0.656, P<0.01); and the amelioration in renal lesion was associated with the increase in BRS (r=0.763, P<0.01) and the decrease in systolic BPV (r=0.706, P<0.01).

CONCLUSION

Long-term treatment with a combination of low-doses of amlodipine and irbesartan showed significant synergism on reduction of BP and BPV, restoration of BRS and organ protection in SHR. Besides BP reduction, the enhancement of BRS and reduction of BPV might contribute to the organ protection.

Nifedipine versus carvedilol in the treatment of de novo arterial hypertension after liver transplantation: results of a controlled clinical trial

The aim of this study was to compare nifedipine and carvedilol in the treatment of de novo arterial hypertension after orthotopic liver transplantation (OLT). The study included 50 patients who developed arterial hypertension after OLT. Twenty-five patients received nifedipine (group A), and 25 received carvedilol (group B). Patients were defined as intolerant to nifedipine or carvedilol if severe adverse effects developed. These patients stopped the first drug and were switched to the other one. Patients were defined as full responders to monotherapy if there was normalization of blood pressure, and they were defined as partial responders by the need to add a second antihypertensive drug, ramipril. The 2 groups of patients were similar for baseline conditions. At the end of the study, patients intolerant to monotherapy were 48% of group A and 12.5% of group B (P < 0.01). Full responders were 20% of group A and 33.33% of group B (P < 0.01). Partial responders were 22% of group A and 54.1% of group B (P < 0.01). The addition of ramipril normalized blood pressure in 19% of partial responders to monotherapy (75% in partial responders to nifedipine and 30% in partial responders to carvedilol, P < 0.01). In responders to either monotherapy or combined therapy, there was a significant improvement of renal function. In responders to carvedilol, but not in responders to nifedipine, the daily dose of tacrolimus at 1 year should be reduced to 50% compared to the baseline dose to maintain the blood trough level in the therapeutic range.

Review: Concomitant calcium entry blockade and inhibition of the renin-angiotensin system: a rational and effective means for treating hypertension

Pharmacological treatment of hypertension is effective in preventing cardiovascular and renal complications. Calcium antagonists (CAs) and blockers of the renin-angiotensin system [angiotensin-converting enzyme (ACE) inhibitors and angiotensin II antagonists (ARBs)] are widely used today to initiate antihypertensive treatment but, when given as monotherapy, do not suffice in most patients to normalise blood pressure (BP). Combining a CA and either an ACE-inhibitor or an ARB considerably increases the antihypertensive efficacy, but not at the expense of a deterioration of tolerability. Several fixed-dose combinations are available (CA + ACE-inhibitors: amlodipine + benazepril, felodipine + ramipril, verapamil + trandolapril; CA + ARB: amlodipine + valsartan). They are expected not only to improve BP control, but also to facilitate long-term adherence with ON antihypertensive therapy, thereby providing renal damage caused by high BP. maximal protection against the cardiovascular and renal damage caused by high BP.

Recurrent headache as the main symptom of acquired cerebral toxoplasmosis in nonhuman immunodeficiency virus-infected subjects with no lymphadenopathy: the parasite may be responsible for the neurogenic inflammation postulated as a cause of different types of headaches

Headache and/or migraine, a common problem in pediatrics and internal medicine, affect about 5% to 10% children and adolescents, and nearly 30% of middle-aged women. Headache is also one of the most common clinical manifestations of acquired Toxoplasma gondii infection of the central nervous system (CNS) in immunosuppressed subjects. We present 11 apparently nonhuman immunodeficiency virus-infected children aged 7 to 17 years (8 girls, 3 boys) and 1 adult woman with recurrent severe headaches in whom latent chronic CNS T. gondii infection not manifested by enlarged peripheral lymph nodes typical for toxoplasmosis, was found. In 7 patients, the mean serum IgG Toxoplasma antibodies concentration was 189 +/- 85 (SD) IU/mL (range 89 to 300 IU/mL), and in 5 other subjects, the indirect fluorescent antibody test titer ranged from 1:40 to 1:5120 IU/mL (n= <1:10 IU/mL). Some of the patients suffered also from atopic dermatitis (AD) and were exposed to cat and/or other pet allergens, associated with an increased IL-4 and decreased IFN-gamma production. These cytokine irregularities caused limited control of cerebral toxoplasmosis probably because IL-4 down-regulated both the production of IFN-gamma and its activity, and stimulated production of a low NO-producing population of monocytes, which allowed cysts rupture, increased parasite multiplication and finally reactivation of T. gondii infection. The immune studies performed in 4 subjects showed a decreased percentage of T lymphocytes, increased total number of lymphocytes B and serum IgM concentration, and impaired phagocytosis. In addition, few of them had also urinary tract diseases known to produce IL-6 that can mediate immunosuppressive functions, involving induction of the anti-inflammatory cytokine IL-10. These disturbances probably resulted from the host protective immune reactions associated with the chronic latent CNS T. gondii infection/inflammation. This is consistent with significantly lower enzyme indoleamine 2,3-dioxygenase (IDO) activity reported in atopic than in nonatopic individuals, and an important role that IDO and tryptophan degradation pathways plays in both, the host resistance to T. gondii infection and its reactivation. Analysis of literature information on the subjects with different types of headaches caused by foods, medications, and other substances, may suggest that their clinical symptoms and changes in laboratory data result at least in part from interference of these factors with dietary tryptophan biotransformation pathways. Several of these agents caused headache attacks through enhancing NO production via the conversion of arginine to citrulline and NO by the inducible nitric oxide synthase enzyme, which results in the high-output pathway of NO synthesis. This increased production of NO is, however, quickly down-regulated by NO itself because this biomolecule can directly inactivate NOS, may inhibit Ia expression on IFN-gamma-activated macrophages, which would limit antigen-presenting capability, and block T-cell proliferation, thus decreasing the antitoxoplasmatic activity. Moreover, NO inhibits IDO activity, thereby suppressing kynurenine formation, and at least one member of the kynurenine pathway, 3-hydroxyanthranilic acid, has been shown to inhibit NOS enzyme activity, the expression of NOS mRNA, and activation of the inflammatory transcription factor, nuclear factor-kB. In addition, the anti-inflammatory cytokines IL-4 and IL-10, TGF-beta, and a cytokine known as macrophage deactivating factor, have been shown to directly modulate NO production, sometimes expressing synergistic activity. On the other hand, IL-4 and TGF-beta can suppress IDO activity in some cells, for example human monocytes and fibroblasts, which is consistent with metabolic pathways controlled by IDO being a significant contributor to the proinflammatory system. Also, it seems that idiopathic intracranial hypertension, pseudotumor cerebri, and aseptic meningitis, induced by various factors, may result from their interference with IDO and inducible nitric oxide synthase activities, endogenous NO level, and cytokine irregularities which finally affect former T. gondii status 2mo in the brain. All these biochemical disturbances caused by the CNS T. gondii infection/inflammation may also be responsible for the relationship found between neurologic symptoms, such as headache, vertigo, and syncope observed in apparently immunocompetent children and adolescents, and physical and psychiatric symptoms in adulthood. We therefore believe that tests for T. gondii should be performed obligatorily in apparently immunocompetent patients with different types of headaches, even if they have no enlarged peripheral lymph nodes. This may help to avoid overlooking this treatable cause of the CNS disease, markedly reduce costs of hospitalization, diagnosis and treatment, and eventually prevent developing serious neurologic and psychiatric disorders.

Medications and substances as a cause of headache: a systematic review of the literature

Medication- or substance-induced headache is probably an underrecognized entity with numerous etiologies, including prescribed medication, over-the-counter medication, illicit drugs, anesthetic agents, foods, food additives, beverages, vitamins, inhaled substances, and substances used in diagnostic procedures. The author performs a systemic review of the literature to provide an exhaustive description of the relationship between medications and substances and headaches of various types, along with pathophysiologic mechanisms whenever possible. Suggestions for improved identification of this phenomenon and its avoidance are provided. More scientific evaluation of substances and their possible association with headache is required with almost all substances indicated herein.

Evaluation of amlodipine, lisinopril, and a combination in the treatment of essential hypertension

Angiotensin converting enzyme (ACE) inhibitors and dihydropyridine calcium antagonists are well established and widely used as monotherapy in patients with mild to moderate essential hypertension. Earlier studies combining short acting drugs from these classes require multiple dosing and were associated with poor compliance. Availability of longer acting compounds allows once daily administration to avoid the inconvenience of a multiple daily dose. It was decided to perform a randomised double blind, crossover study with the long acting calcium channel blocker amlodipine and the long acting ACE inhibitor lisinopril, given either alone or in combination in essential hypertension. Twenty four patients with diastolic blood pressure (DBP) between 95 and 104 mm Hg received amlodipine 2.5 mg and 5 mg, lisinopril 5 mg and 10 mg, and their combination as per a prior randomisation schedule. Supine and standing blood pressure and heart rate were recorded at weekly intervals. Higher doses of both the drugs individually or in combination were used if the target supine DBP below 90 mm Hg was not achieved. There was a significant additional blood pressure lowering effect with the combination when compared either with amlodipine or lisinopril alone. Five mg amlodipine and 10 mg lisinopril monotherapy achieved the target blood pressure in 71% and 72% patients respectively. The combination of 2.5 mg amlodipine with 5 mg lisinopril produced a much more significant lowering of blood pressure in a higher percentage of patients than that with an individual low dose.

Evaluation of enalapril combined with diltiazem ER in patients with stage 3-4 essential hypertension

Enalapril combined with an extended-release formulation of diltiazem was evaluated in a 12-week multicenter trial of 112 patients with Stages 3-4 essential hypertension. Patients were randomized to once daily therapy with enalapril 5 mg plus diltiazem ER 120 mg or 180 mg. Dosages could be titrated and other antihypertensive agents added for blood pressure control. Efficacy was assessed with sitting blood pressures at trough (24 hours postdose). Overall, there was a decrease of -21.7/-18.4 mmHg. Patients responding to enalapril/diltiazem ER alone had a reduction of -15.0/-16.3 mmHg. Of all patients, 70% achieved a trough sitting diastolic blood pressure of < 95 mmHg. Common drug-related adverse experiences were headache, dizziness, rash, and asthenia/fatigue. This once daily fixed-combination of enalapril/diltiazem ER was generally well tolerated and effective when given alone or with other antihypertensives in Stage 3-4 hypertension.

Clinical utility of long-term enalapril/diltiazem ER in stage 3-4 essential hypertension. Long-term Use of Enalapril/Diltiazem ER in Stage 3-4 Hypertension Group

The use of angiotensin converting enzyme inhibitors and calcium channel blockers, as monotherapies and in combination, is common in the management of hypertension. Clinical studies have documented the augmentation of blood pressure reduction when these agents are combined compared with the individual agents, in short-term studies. In the present investigation, 93 patients with stage 3-4 essential hypertension, who successfully completed a short-term double-blind study, participated in a 40-week open-label treatment phase. The patients were maintained on their previous doses of enalapril/diltiazem ER (E/D) with or without additional antihypertensive medications. Doses of medication could be adjusted as necessary for blood pressure control. Of the 93 patients, 68% were male and 82% were white; they averaged 52.7 years of age and had a baseline mean sitting blood pressure (SiBP) of 167/111 mmHg. The use of E/D alone (n = 14) reduced mean SiBP by 14.5/14.4 mmHg from baseline, whereas the use of E/ D with other agents (n = 79) decreased it by 27/20.5 mmHg from baseline. E/D alone or in combination with other drugs was well-tolerated, and no serious adverse events were noted. This long-term open-label study demonstrated that the E/D combination alone or with the addition of other antihypertensive drugs was effective, safe, and well-tolerated after prolonged administration.

Comparison of amlodipine and benazepril monotherapy to amlodipine plus benazepril in patients with systemic hypertension: a randomized, double-blind, placebo-controlled, parallel-group study. The Benazepril/Amlodipine Study Group

A single-blind, run-in, randomized, double-blind, parallel-group, placebo-controlled comparison trial was conducted to assess the safety and efficacy of low-dose amlodipine 2.5 mg daily, low-dose benazepril 10 mg daily, and the combination of the two drugs at the same doses used once daily in patients (n = 401) with mild to moderate (stages I and II) systemic hypertension. Both monotherapy regimens were shown to significantly reduce both systolic and diastolic blood pressure compared with baseline placebo values, and the combination regimen was shown to be superior in lowering systolic and diastolic blood pressure when compared with either of the monotherapy regimens. The combination therapy also resulted in a greater percentage of patients having successful clinical response in mean sitting diastolic blood pressure. The amlodipine and benazepril regimen was also shown to be associated with a similar incidence of adverse experiences as the active monotherapy or placebo regimens, although the group given combination therapy appeared to have a lower incidence of edema than the group given amlodipine alone. Low-dose amlodipine (2.5 mg) plus benazepril (10 mg) provides greater blood-pressure-lowering efficacy than either monotherapy, and has an excellent safety profile.

Comparative effects of fosinopril and nifedipine on regression of left ventricular hypertrophy in hypertensive patients: a double-blind study

The effects of fosinopril and nifedipine on left ventricular (LV) mass were evaluated in 35 hypertensive patients with LV mass index greater than 110 g/m2 in female and 130 g/m2 in male patients. The goal of therapy was also to obtain a seated diastolic blood pressure (SDBP) of less than 90 mmHg. The patients were studied by echocardiography after 2 weeks of placebo treatment and 4, 12, and 24 weeks of monotherapy with active drugs. Both fosinopril and nifedipine reduced SDBP to a normal level after 6 months of treatment (p < .001). Regression of LV hypertrophy was achieved by either agent (p < .001), with fosinopril being more effective than nifedipine (p < .002). In conclusion, both fosinopril and nifedipine effectively reduce SDBP and achieve important regression of LV hypertrophy.

Combination drug therapy with calcium-channel blockers in the treatment of systemic hypertension

Calcium-channel blockers have been shown to be both safe and effective for treatment of patients with systemic hypertension. These drugs reduce peripheral vascular resistance predominantly by the inhibition of transmembrane calcium ion fluxes in vascular smooth muscle, and by this mechanism can reduce elevated blood pressure. To maximize blood pressure lowering efficacy in patients, calcium-channel blockers have also been used in combination with other antihypertensive treatments that have included diuretics, beta-adrenergic blockers, and angiotensin-converting enzyme inhibitors.