Hydralazine for treatment of severe hypertension in pregnancy: meta-analysis

OBJECTIVE

To review outcomes in randomised controlled trials comparing hydralazine against other antihypertensives for severe hypertension in pregnancy.

STUDY DESIGN

Meta-analysis of randomised controlled trials (published between 1966 and September 2002) of short acting antihypertensives for severe hypertension in pregnancy. Independent data abstraction by two reviewers. Data were entered into RevMan software for analysis (fixed effects model, relative risk and 95% confidence interval); in a secondary analysis, risk difference was also calculated.

RESULTS

Of 21 trials (893 women), eight compared hydralazine with nifedipine and five with labetalol. Hydralazine was associated with a trend towards less persistent severe hypertension than labetalol (relative risk 0.29 (95% confidence interval 0.08 to 1.04); two trials), but more severe hypertension than nifedipine or isradipine (1.41 (0.95 to 2.09); four trials); there was significant heterogeneity in outcome between trials and differences in methodological quality. Hydralazine was associated with more maternal hypotension (3.29 (1.50 to 7.23); 13 trials); more caesarean sections (1.30 (1.08 to 1.59); 14 trials); more placental abruption (4.17 (1.19 to 14.28); five trials); more maternal oliguria (4.00 (1.22 to 12.50); three trials); more adverse effects on fetal heart rate (2.04 (1.32 to 3.16); 12 trials); and more low Apgar scores at one minute (2.70 (1.27 to 5.88); three trials). For all but Apgar scores, analysis by risk difference showed heterogeneity between trials. Hydralazine was associated with more maternal side effects (1.50 (1.16 to 1.94); 12 trials) and with less neonatal bradycardia than labetalol (risk difference -0.24 (-0.42 to -0.06); three trials).

CONCLUSIONS

The results are not robust enough to guide clinical practice, but they do not support use of hydralazine as first line for treatment of severe hypertension in pregnancy. Adequately powered clinical trials are needed, with a comparison of labetalol and nifedipine showing the most promise.

A predictive equation for drug-induced lupus

Objective was to quantify the chemical mechanisms of drug-induced lupus (DIL), and to make the data of different authors comparable between them. I have used seven assumptions as a starting point, based on empirical evidence; then an equation is drawn, describing the relationship between the quantity of the drug taken by the patient(s) and the probability of DIL appearance. The DIL-causing potential of each chemical group is a measurable intrinsic characteristic of that group, and the probability of DIL appearance is directly proportional to the total dosage of the drug in question.

CONCLUSIONS

DIL is a syndrome that can be readily quantified and, as such, could be used as a model for idiopathic Systemic Lupus Erythematosus. On the other hand, the equation drawn here could be used to predict the lupus-inducing potential of many compounds that have not yet been studied. Other authors are encouraged to find similar equations in other drug-induced syndromes.

P-ANCA positive renal vasculitis in association with renal cell carcinoma and prolonged hydralazine therapy

Renal cell carcinoma and hydralazine drug therapy has each been reported as rare associations with pauci-immune renal vasculitis. We report a patient in whom both factors were operative simultaneously. A middle-aged man on long term hydralazine therapy presented with advanced renal failure. Serum was strongly positive for P-ANCA with high anti-myeloperoxidase (MPO) titre and renal biopsy showed focal necrotizing glomerulonephritis. A renal mass was identified on scanning and at left nephrectomy a large renal cell carcinoma was removed. In spite of an apparently curative operation and discontinuation of hydralazine, P-ANCA remains strongly positive, he has had no recovery of renal function and has progressed to dialysis dependence.

Hydralazine may induce autoimmunity by inhibiting extracellular signal-regulated kinase pathway signaling

OBJECTIVE

To determine whether hydralazine might decrease DNA methyltransferase (DNMT) expression and induce autoimmunity by inhibiting extracellular signal-regulated kinase (ERK) pathway signaling.

METHODS

The effect of hydralazine on DNMT was tested in vitro using enzyme inhibition studies, and in vivo by measuring messenger RNA (mRNA) levels and enzyme activity. Effects on ERK, c-Jun N-terminal kinase, and p38 pathway signaling were tested using immunoblotting. Murine T cells treated with hydralazine or an ERK pathway inhibitor were injected into mice and anti-DNA antibodies were measured by enzyme-linked immunosorbent assay.

RESULTS

In vitro, hydralazine did not inhibit DNMT activity. Instead, hydralazine inhibited ERK pathway signaling, thereby decreasing DNMT1 and DNMT3a mRNA expression and DNMT enzyme activity similar to mitogen-activated protein kinase kinase (MEK) inhibitors. Inhibiting T cell ERK pathway signaling with an MEK inhibitor was sufficient to induce anti-double-stranded DNA antibodies in a murine model of drug-induced lupus, similar to the effect of hydralazine.

CONCLUSION

Hydralazine reproduces the lupus ERK pathway signaling abnormality and its effects on DNMT expression, and inhibiting this pathway induces autoimmunity. Hydralazine-induced lupus could be caused in part by inducing the same ERK pathway signaling defect that occurs in idiopathic lupus.

Management of hypertensive emergencies of pregnancy by hydralazine bolus injection vs continuous drip--a comparative study

This prospective study was conducted at Dhaka Medical College and Hospital, Bangladesh. The objective was to identify the time required to control high blood pressure levels in obstetric patients by injection of hydralazine in a bolus intravenous dose vs continuous drip. Seventy-seven patients with eclampsia and hypertensive emergencies comprised the target population. Patients were managed either by hydralazine drip in normal saline (existing official protocol, n = 33) or hydralazine bolus injection (as experiment, n = 44) until diastolic blood pressure fell to 90-95 mmHg. Results were compared. Student's t-test was done for statistical significance, and a P value of <.05 was considered as significant. The groups were similar with respect to maternal age and their mean systolic and diastolic blood pressure at the time of enrollment. Patients who received bolus injection required less time to achieve the therapeutic goal (65.23 +/- 23.38 minutes) than continuous drip (186.36 +/- 79.77 minutes; P <.001). The experimental group also required significantly lower doses (6.68 +/- 1.66 mg) in comparison to that required by control group (20.07 +/- 11.38 mg; P <.001). There was no overshoot hypotension in either group. The data suggest that hydralazine bolus dose is equally safe and more effective than continuous drip in the management of hypertensive emergencies in pregnancy.

Drug-associated antineutrophil cytoplasmic antibody-positive vasculitis: prevalence among patients with high titers of antimyeloperoxidase antibodies

OBJECTIVE

The triggers that induce antineutrophil cytoplasmic antibody (ANCA)-positive vasculitis (APV) are largely unknown. However, there have been reports suggesting that hydralazine, propylthiouracil, and several other drugs may cause some cases of APV, and the majority of these cases have been associated with antimyeloperoxidase (anti-MPO) ANCA. Our experience led us to hypothesize that cases of high titers of anti-MPO antibodies are often drug-associated.

METHODS

In this study, we determined the prevalence of exposure to hydralazine, propylthiouracil, and other drugs previously implicated in APV among 30 patients with vasculitis and the highest titers of anti-MPO antibodies newly detected in our laboratory between 1994 and 1998. The clinical, histologic, and other serologic features of these 30 patients were also examined.

RESULTS

The 30 study patients accounted for 12% of the 250 new patients with APV and anti-MPO who were tested during the study period. All 30 study subjects had anti-MPO titers that were more than 12 times the median titer of the 250 patients. Ten (33%) of the 30 patients had been exposed to hydralazine and 3 (10%) had been exposed to propylthiouracil. An additional 5 patients (17%) had been exposed to 1 of the other previously reported candidate drugs: 2 to penicillamine, 2 to allopurinol, and 1 to sulfasalazine. One of the patients exposed to hydralazine had also been exposed to allopurinol. In all cases, the clinical and histologic findings were typical of APV. There was a strong association between the presence of antielastase and/ or antilactoferrin antibodies and exposure to candidate drugs.

CONCLUSION

These data suggest that a sizable proportion of cases of APV with high titers of anti-MPO antibodies are drug-associated, especially following exposure to hydralazine or propylthiouracil. We recommend that the use of these drugs should be sought in cases of anti-MPO-positive vasculitis, particularly among patients with high titers of these antibodies.

Hydralazine-induced lupus and vocal fold paralysis

Systemic lupus erythematosus (SLE) is a multi-system autoimmune disorder that can affect the upper airway. Hydralazine has been known to cause a lupus-like syndrome that can produce the clinical manifestations of SLE. We discuss a case of hydralazine-induced lupus, presenting with acute laryngeal oedema and right vocal fold paralysis. Cessation of hydralazine therapy resulted in reversal of paralysis.

Mechanisms of drug-induced lupus. IV. Comparison of procainamide and hydralazine with analogs in vitro and in vivo

OBJECTIVE

T cells treated with DNA methylation inhibitors overexpress lymphocyte function-associated antigen 1 (LFA-1), which results in autoreactivity, and the autoreactive cells cause a lupus-like disease in vivo, suggesting a mechanism by which some agents may cause drug-induced lupus. This study compared the effects of procainamide (Pca) and hydralazine (Hyd) with those of structural analogs, to determine if the degree of LFA-1 overexpression and T cell autoreactivity correlated with the ability of the agents to induce autoimmunity.

METHODS

Cloned murine T helper 2 cells were treated with Pca, N-acetylprocainamide, Hyd, Phthalazine, or hydroxyurea (HU). The treated cells were then compared for LFA-1 overexpression, autoreactivity, and the ability to induce autoimmunity in vivo.

RESULTS

Pca and Hyd were more potent than their analogs or HU in all 3 assays.

CONCLUSION

The results support a relationship between LFA-1 overexpression, T cell autoreactivity, and autoimmunity, and suggest a mechanism by which Pca and Hyd, but not the analogs, may cause drug-induced lupus.

Hypotension reduces sleep apneas in Zucker lean and Zucker obese rats

The effects of hypotension and obesity on spontaneous apnea (SA) and post-sigh sleep apnea (PSA) were studied in Zucker rats by monitoring blood pressure, respiration, and sleep state for 6 hours. Hypotension produced by intraperitoneal administration of hydralazine (2 mg/kg) was associated with reduced SA and PSA expression in nonrapid eye movement sleep in both lean and obese rats. In both animal groups, hypotension reduced rapid eye movement (REM) sleep by 50% but exerted no significant effect on REM-related expression of SA. Blood pressure lowering also correlated with increased respiratory rate and inspired minute ventilation during sleep, suggesting that the effects of hypotension on apnea expression may arrive via modulation of respiratory drive. These findings emphasize the interdependence of cardiorespiratory functions and may have implications regarding the mechanisms of central apnea in man.

Hydralazine-induced constrictive pericarditis

A 59-year-old man was diagnosed as having constrictive pericarditis 17 months after a typical hydralazine-induced autoimmune syndrome. This late complication of hydralazine has been reported only once. Ten years later the patient was found to have anti-neutrophil cytoplasmic antibodies directed against myeloperoxidase.

Antigen specificity in hydralazine associated ANCA positive systemic vasculitis

The anti-hypertensive agent hydralazine can cause a lupus-like syndrome characterized by serosal inflammation, arthralgias and rashes. The kidneys however are usually spared. The condition is characterized by circulating immune complexes and antinuclear antibodies, whilst antibodies against double-stranded DNA are rare. Hydralazine can also cause a systemic vasculitis with a pauci-immune rapidly progressive glomerulonephritis, which is associated with autoantibodies directed against components of the neutrophil cytoplasm. In this study, ten patients with hydralazine-induced vasculitis had antibodies with specificities for both myeloperoxidase and lactoferrin. We suggest that this particular pattern of autoantibodies, together with antibodies with reactivity against nuclear components including double-stranded DNA, are characteristic findings in hydralazine-induced vasculitis. In addition, renal involvement appears to be more common in this group of patients with vasculitis than in those with the lupus-like syndrome.

Triplex-DNA stabilization by hydralazine and the presence of anti-(triplex DNA) antibodies in patients treated with hydralazine

Hydralazine is an antihypertensive drug that elicits andti-nuclear antibodies in patients as an adverse effect. We investigated the ability of hydralazine to promote/stabilize the triplex DNA form of poly(dA).2poly(dT). Under conditions of low ionic strength, the polynucleotide melted as a double helix with a melting temperature (Tm) of 55.3 degrees C. Hydralazine destabilized this duplex form by reducing its Tm to 52.5 degrees C. Spermidine (2.5 microM), a natural polyamine, provoked the triplex form of poly(dA)-.2poly(dT) with two melting transitions, Tm1 of 42.8 degrees C corresponding to triplex-->duplex+single-stranded DNA and Tm2 of 65.4 degrees C, corresponding to duplex melting. Triplex DNA thus formed in the presence of spermidine was further stabilized by hydralazine (250 microM) with a Tm1 of 53.6 degrees C. A similar stabilization effect of hydralazine was found on triplex DNA formed in the presence of 5 mM Mg2+. CD spectra revealed conformational perturbations of DNA in the presence of spermidine and hydralazine. These results support the hypothesis that hydralazine is capable of stabilizing unusual forms of DNA. In contrast with the weak immunogenicity of DNA in its right-handed B-DNA conformation, these unusual forms are immunogenic and have the potential to elicit anti-DNA antibodies. To test this possibility, we analysed sera from a panel of 25 hydralazine-treated patients for anti-(triplex DNA) antibodies using an ELISA. Our results showed that 72% of sera from hydralazine-treated patients contained antibodies reacting toward the triplex DNA. In contrast, there was no significant binding of normal human sera to triplex DNA. Taken together our data indicate that hydralazine and related drugs might exert their action by interacting with DNA and stabilizing higher-order structures such as the triplex DNA.

Drug-induced Sweet's syndrome (acute febrile neutrophilic dermatosis) associated with hydralazine

We report a case of Sweet's syndrome associated with hydralazine. The association of Sweet's syndrome with hydralazine, and with the oral contraceptive, minocycline, and trimethoprim/sulphamethoxazole, has been reported previously. We suggest that a drug aetiology should be sought in cases of Sweet's syndrome.

Quinidine-induced rheumatic syndromes

Quinidine is a commonly used antiarrhythmic agent that is rarely associated with rheumatologic toxicity. However, quinidine-induced lupus, antinuclear antibody negative lupus-like syndrome, polymyalgia rheumatica-like illness, muscle weakness, and isolated creatine phosphokinase elevation have all been reported. We present one case of quinidine drug-induced lupus and another of a quinidine-induced polymyalgia rheumatica-like illness, and review the English literature for rheumatologic toxicity due to quinidine. Prompt recognition of quinidine associated rheumatologic toxicity is important because discontinuation of the medication leads to rapid resolution of clinical symptoms.

Beta-adrenergic blocking agents in the treatment of pregnancy-induced hypertension

Fifty-one women with pregnancy-induced hypertension (PIH) were randomly allocated to one of three treatment groups: A: hydralazine (13); B: hydralazine and propranolol (17); and C: hydralazine and pindolol (19). All women fulfilled the pretreatment criteria and were of similar age, numbers of previous pregnancies and had systolic blood pressure (SBP) of between 140 and 160 mmHg and diastolic blood pressure (DBP) of between 95 and 110 mmHg. Hypertension was treated equally well by all three regimens (mean SBP was 133.6, 130 and 134 mmHg, respectively). Heart rate was significantly higher than baseline in group A and lower in groups B and C, as is to be expected with beta-blocker treatment. Side-effects were more frequent in group A than in groups B and C, 62% of the patients on hydralazine monotherapy complained of palpitations compared to 35% on combination treatment. Fetal outcome differed in the various groups. Birth weight was significantly lower in group B, where regimen included propranolol, compared to that of group C, for whom the regimen included pindolol (3,044.7 +/- 443.8 and 2,709.6 +/- 485.5 gm, p < 0.05). Mean blood glucose of the newborns were similar in groups A and C (76.5 +/- 16.5 and 78.6 +/- 15 gm%) and significantly lower in group B (62.6 +/- 14 gm%, p < 0.02). In conclusion, blood pressure was equally well treated in all three treatment groups. However, more maternal side-effects occurred in group A, the group treated with hydralazine monotherapy, while propranolol in combination with hydrazaline (group B) had some negative effects on fetal development which did not occur in pindolol/hydrazaline combination.

Topically applied hydralazine: effects on systemic cardiovascular parameters, blood-aqueous barrier, and aqueous humor dynamics in normotensive humans

Local application of hydralazine has been found to alter intraocular pressure in animal eyes. This study was undertaken to determine, in normotensive humans, the effects of topically-applied hydralazine on systemic cardiovascular parameters, blood-aqueous barrier, and aqueous humor flow. Two different concentrations of hydralazine were used: 0.03%, and 0.1%. Twenty healthy normotensive subjects were studied. Blood pressure, pulse rate, and intraocular pressure were measured every hour for six hours after hydralazine or placebo was instilled into the conjunctival sac in a double-masked, randomized fashion. With either hydralazine dose, there was no significant change in systemic blood pressure or pulse. In addition, spectrophotometrically-measured polarization of fluorescence and flare failed to show any significant breakdown of the blood-aqueous barrier. In most individuals, application of hydralazine was followed by a brief, mild to moderate, conjunctival hyperemic response. Compared to placebo at the same time of day, a small increase in intraocular pressure was observed with 0.03% hydralazine (p < .05). At 0.1%, this increase tended to be less. There was no statistically significant difference in aqueous humor flow between hydralazine-treated and placebo-treated eyes at the lower concentration (3.20 +/- 0.63 vs. 3.05 +/- 0.61 microL/min (mean +/- S.D.) or at the higher concentration (3.37 +/- 0.53 vs. 3.28 +/- 0.60 microL/min) of hydralazine. These results suggest that acute topical application of 0.1% hydralazine to the eyes of normal humans does not cause clinically significant cardiovascular effects or significant ocular toxicity.

Effect of acute cytomegalovirus infection on drug-induced SLE

A 58 year old woman developed systemic symptoms, interstitial lung disease, splenomegaly, leukopenia and anti-histone and anti-nuclear antibodies (ANA), while treated with hydralazine for hypertension. Five months after presentation she was admitted with high fever, skin rash and atypical lymphocytosis due to acute cytomegalovirus (CMV) infection. Worsening leukopenia and increased ANA were found, and high titres of anti-DNA antibodies, anti-cardiolipin antibodies and rheumatoid factors appeared. Hydralazine was stopped and the patient gradually became asymptomatic. All autoantibodies spontaneously disappeared (over 16 weeks), and the white cell count and spleen size became normal. The patient was found to be a slow acetylator and to have both HLA-DR4 and selective IgA deficiency. Thus, a multifactorial genetic susceptibility to develop drug-induced lupus was brought out in stages first by hydralazine and then by CMV, yet all manifestations and autoantibodies resolved spontaneously, demonstrating the complex interplay of varied environmental factors with a genetic predisposition in the pathogenesis of autoimmunity.

Occurrence of autoantibodies directed against myeloperoxidase and elastase in patients treated with hydralazine and presenting with glomerulonephritis

We have undertaken an investigation retrospectively of 21 patients with positive antinuclear antibodies, who had been on hydralazine treatment and developed a glomerulonephritis. Four patients had circulating antimyeloperoxidase (MPO) and two of them were concluded to have a hydralazine-induced glomerulonephritis, corresponding to a frequency of 10%. These two patients had antibodies of IgG and IgM class directed against myeloperoxidase (MPO), and also antibodies against elastase. These two patients had also a biopsy proven extracapillary glomerulonephritis with focal segmental necrosis. Antibodies against elastase were furthermore seen in three patients with proliferative glomerulonephritis and in one patient with membranoproliferative glomerulonephritis. This study confirms an association between circulating anti-MPO and a histopathological picture compatible with extracapillary proliferation and focal segmental necrosis. From a clinical, histopathological and serological point of view it can be concluded that in two patients the glomerulonephritis was associated with antibody evidence of an autoimmune side effect.

Management of eclampsia

Mrs AB was admitted in the 34th week of pregnancy with eclampsia. Prompt parenteral (intravenous and intramuscular) administration of magnesium sulfate arrested the convulsions and prevented additional seizures. Because of a dangerously elevated blood pressure, intravenous hydralazine was administered to reduce the blood pressure. Unfortunately, the hydralazine was given more frequently than recommended, and the blood pressure was decreased rapidly and too far. This resulted in the development of a serious fetal bradycardia secondary to reduced uteroplacental perfusion. Fortunately, the blood pressure spontaneously recovered as did the fetus. Three hours after admission, Mrs AB was awake and alert. Her fetus had also recovered from the effects of the convulsions and the treatment with hydralazine. Mrs AB's laboratory values had all been reported by this time, and her intravenous intake and urinary output were well regulated. Importantly, because of the presence of significant hemoconcentration (hematocrit at 32 weeks' was 36 and at 34 weeks', 44), a careful search for pulmonary edema was made. Additionally, fluid administration was conservative in order not to produce pulmonary edema. At this point, an induction of labor was commenced. The induction of labor was rapidly successful, and Mrs AB delivered a small but vigorous male infant who subsequently did well. Mrs AB was monitored hourly for the first 12 hours postpartum to ensure adequate blood pressure control and to prevent pulmonary edema. Her subsequent puerperal course was without adverse incident. She diuresed massively, and her blood pressure rapidly returned to normal.

Autoantibodies to myeloperoxidase in idiopathic and drug-induced systemic lupus erythematosus and vasculitis

Circulating antibodies to myeloperoxidase (MPO) have been described in a variety of vasculitic syndromes, drug-induced SLE and drug-induced nephritis. We have examined the autoantibody profile in acute sera from patients with antineutrophil cytoplasmic antibody-positive vasculitis (n = 8), drug-induced nephritis (n = 4), drug-induced lupus (n = 7), SLE (n = 27) and nephritis-associated with SLE (n = 17). Significant binding to purified MPO in ELISA was given by all sera from patients with vasculitis and drug-induced nephritis but ANA sought by indirect immunofluorescence on HEp-2 cells were not detected. Both anti-MPO and ANA were found in sera from patients with drug-induced lupus. Sera from patients with SLE or SLE nephritis did not contain high titres of anti-MPO antibodies but invariably contained ANA. Anti-MPO antibodies of both IgG and IgM classes were present in all sera from patients with drug-induced disease. Although the number of samples tested was small, sera from patients with drug-induced nephritis showed significantly greater median % binding of IgM to MPO compared with drug-induced SLE. Binding to MPO by IgG in these sera was not significantly different. These findings suggest that the mechanism of interaction between hydralazine and the immune system in the two drug-induced autoimmune diseases studied may contribute to their distinct clinical features.

Occurrence of anti-lactoferrin antibodies in patients with systemic lupus erythematosus, hydralazine-induced lupus, and rheumatoid arthritis

Antibodies directed against neutrophil granulocyte components have gained an increasing importance in diagnosing systemic vasculitis diseases. The present study was aimed to investigate distribution of anti-lactoferrin antibodies in systemic lupus erythematosus, the hydralazine-induced SLE-like syndrome, and in rheumatoid arthritis compared to RA complicated with vasculitis. Antibodies were detected by ELISA and verified by Western blotting and inhibition assay. Sera positive for IgM were absorbed to remove the rheumatoid factor. IgG and IgM anti-lactoferrin antibodies were found in SLE in 5% and 10% respectively. All patients with hydralazine-induced SLE had antibodies of both isotypes and the antibody level declined rapidly after withdrawal of the drug. In rheumatoid arthritis no IgG anti-lactoferrin antibodies were found, but 20% of the patients with vasculitis had IgM antibodies. Anti-lactoferrin antibodies seem partly to discriminate between genuine and hydralazine-induced SLE, which might indicate a pathogenic relevance in drug-induced autoimmunity. In uncomplicated rheumatoid arthritis it can be concluded that anti-lactoferrin antibodies lack clinical, as well as pathogenic relevance.

Comparison of outcome of labetalol or hydralazine therapy during hypertension in pregnancy in very low birth weight infants

Ninety-seven women with moderate to severe preeclampsia (PE) were allocated at random to labetalol or hydralazine treatment. Of these, 22 women with severe PE gave birth to neonates with VLBW (very low birth weight < or = 1500 g). Seven were allocated to labetalol treatment (Group A), eight to hydralazine treatment (Group B) and seven women received both drugs due to poor blood pressure control with a single drug therapy (Group C). No difference in cesarean section rate or in the indication for operative delivery could be seen. Gestational age was 29.9 weeks (25.4-32.5) in Group A, 28.6 weeks (26.6-33.4) in Group B and 27.3 weeks (26.7-31.1) in Group C (median and range). Birth weight did not differ between groups and 13 of the 22 infants weighed below 1000 g. There was a tendency to lower Apgar scores at five minutes in the hydralazine group. Time spent in the neonatal intensive care unit did not differ between groups. Five of the 11 neonates with gestational age (GA) < or = 28 weeks and three of the seven neonates in GA 29-30 weeks died. Neither the number of infants requiring intermittent positive pressure ventilation or duration of O2- treatment, nor number of infants with respiratory distress syndrome differed between groups. We did not find any difference in the outcome of the VLBW infants when the hypertensive mother had been treated with either hydralazine or labetalol.

Hydralazine induces Z-DNA conformation in a polynucleotide and elicits anti(Z-DNA) antibodies in treated patients

We studied the effect of hydralazine, an antihypertensive drug with lupus-inducing side effects, on the conformation of poly(dG-m5dC).poly(dG-m5dC) and a plasmid with a 23 bp insert of (dG-dC)n.(dG-dC)n sequences. Using an e.l.i.s.a. with a monoclonal anti-(Z-DNA) antibody Z22, we found that hydralazine provoked the Z-DNA conformation in poly(dG-m5dC).poly(dG-m5dC) at 250-500 microM concentration. The supercoiled form of hydralazine-treated plasmid bound to Z22 in a gel-retardation assay. To examine further whether Z-DNA could act as an inciting agent in anti-nuclear antibody production in patients, we analysed 65 sera from 25 hypertensive patients taking hydralazine and found anti-(Z-DNA) antibodies in 82% of these sera. Sera from age-matched normal controls showed no binding to Z-DNA. Data on sera drawn sequentially from four hypertensive patients showed that antibodies were present after the drug treatment. These data demonstrate the presence of a high incidence of anti-(Z-DNA) antibodies in patients treated with hydralazine and suggest that a possible mechanism for the production of autoantibodies in drug-related lupus might involve the induction and stabilization of Z-DNA by drugs.

Hydralazine predisposes to acute cutaneous vasculitis following urography with iopamidol

We report a 60-year-old woman with renovascular hypertension who developed a severe cutaneous vasculitis 24 h after the injection of iopamidol during urography. A review of the literature suggests that her concomitant hydralazine therapy probably predisposed her to this reaction, as similar reactions have occurred in systemic lupus erythematosus, and hydralazine can induce a LE-like syndrome. We recommend that urography should be avoided in patients receiving hydralazine.

Comparison of captopril, hydralazine and nifedipine as third drug in hypertensive patients

The antihypertensive, biochemical and adverse effects of captopril, hydralazine, nifedipine and placebo were compared in 160 patients with BP inadequately controlled by atenolol 100 mg daily plus bendrofluazide 5 mg daily. Treatments were given for up to 12 weeks. Beta-blocker and thiazide were continued unchanged. All three active drugs reduced supine BP relative to placebo; mean BP changes attributable to active treatment (95% confidence intervals): captopril 13.4/10.3 mmHg (0.6/4.0 to 26.2/16.6), hydralazine 15.0/10.0 mmHg (1.7/3.4 to 28.3/16.6), nifedipine 16.8/8.1 mmHg (4.0/1.8 to 29.6/14.4). There were no significant differences between the agents. Results for erect BP were similar. Target BP (< 140/95 mmHg) was achieved more frequently on captopril (33%), hydralazine (29%) and nifedipine (17%) than on placebo (10%). Compared with the other treatments captopril increased serum potassium concentration (P = 0.01), and hydralazine reduced serum cholesterol concentration (median changes: captopril -0.2 mmol/l, hydralazine -0.8 mmol/l, nifedipine -0.2 mmol/l, and placebo +0.2 mmol/l, P < 0.001). Overall, side-effects did not differ significantly between the groups; withdrawals resulting from adverse reactions: captopril 15%, hydralazine 24%, nifedipine 22%, and placebo 3% (chi 2 = 8.2, P = 0.04). Captopril, hydralazine and nifedipine did not differ significantly in efficacy and tolerability when added to atenolol and bendrofluazide. However, there were trends in favour of captopril, on which drug the highest proportion of patients had their BP controlled and the lowest proportion were withdrawn because of side-effects. Thus, of the drugs tested, captopril appears to be the best option as third drug in hypertension.

Neonatal adaptation in hypertensive pregnancy--a study of labetalol vs hydralazine treatment

Twenty mothers with moderate to severe preeclampsia were allocated to labetalol (Trandate) or hydralazine (Apresolin) antihypertensive treatment. Arterial blood gas analysis was performed at delivery from the clamped cord. Neonatal blood pressure, heart rate and axillary temperature were registered 0.5, 2, 6, 12, 24, 36, 48 hours and 3, 4 and 7 days after birth. Respiratory rate was registered at the same intervals until 36 hours after birth. Blood glucose levels were measured 2, 6, 12 and 24 hours after birth. Peripheral blood flow in the calf was measured at 24 hours of age. Gestational age did not differ between the two groups; 36 (27-40) in the labetalol, and 35 (29-37) weeks in the hydralazine group (median and range). Median cord pH was lower, and the number of infants with a cord pH < 7.20 was higher in the hydralazine group. Blood glucose levels were lower in the labetalol group at 6 hours of age (p < 0.05). No other differences were found between the two groups. The conclusion is that no clinical signs of adrenergic blockade have been found at 24 hours of age, and no negative effect of labetalol on the neonatal adaptation compared to hydralazine antihypertensive treatment was found.

Drug-specific immune responses induced by immunization with drugs in guinea pigs and mice

In order to develop a system for evaluating the allergenicity of drugs in clinical use, we tested drugs for the ability to induce drug-specific immune responses in guinea pigs and mice. Test drugs were benzylpenicillin, procainamide, hydralazine, isoniazid, alpha-methyldopa, D-penicillamine, captopril, sulfamethoxazole and 2,4-dinitrochlorobenzene (DNCB), which are known to induce allergic responses in man including hypersensitivity reactions and drug-induced auto-immune responses. Guinea pigs were immunized with an emulsion of complete Freund's adjuvant (CFA) and 25 mg of each drug. Mice were immunized with an emulsion of CFA and 2 mg of each drug or a mixture of aluminum hydroxide gel and 2 mg of each drug. In order to examine drug-specific immune responses, we employed detection of antibodies by enzyme-linked immunosorbent assay (ELISA) and passive cutaneous anaphylaxis tests, active systemic anaphylaxis (ASA) tests and delayed type hypersensitivity (DTH) tests. In guinea pigs, drug-specific antibodies were detected following immunization with benzylpenicillin, procainamide, hydralazine, isoniazid, captopril, sulfamethoxazole or DNCB. Some of these drugs were also positive in DTH tests and/or ASA tests. In mice, however, only DNCB gave positive results. Therefore, our system involving immunization of guinea pigs with CFA emulsion of a drug and detection of drug-specific immune responses is considered to be an effective test method for evaluating drug allergenicity.

Management of hypertensive emergencies

Between 1975 and 1985, 454 patients with hypertension were admitted to the Renal Unit of the Hospital for Sick Children. A total of 110 (24%) patients presented with severely raised blood pressures deemed to require emergency management. At presentation 84/110 had symptoms and signs of long standing hypertension with neurological involvement. Between 1975 and 1980 bolus intravenous injections of diazoxide and/or hydralazine were used with the aim of reducing the blood pressure to within the normal range for age in the first 12-24 hours after admission. Of 57 patients treated in this way 13 developed hypotensive complications and four, whose blood pressures returned to normal within 24 hours of admission, suffered irreversible neurological damage. Subsequently, the management changed to the use of intravenous infusions of labetalol (1-3 mg/kg/hour) and/or sodium nitroprusside (0.5-8 micrograms/kg/min) to enable a more gradual controlled reduction of blood pressure over the first 96 hours of admission. Between 1980 and 1985, 53 patients were treated using this regimen. In all cases blood pressure reduction was achieved in a more controlled manner without further neurological impairment or serious irreversible side effects. From our experience, the use of labetalol and sodium nitroprusside by incremental infusion in the critical early phase of management has resulted in improved control of accelerated hypertension without the sudden hypotensive episodes seen when bolus injections are used.

Medication-induced systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease affecting a variety of tissues and organs. The diagnosis of SLE can be made only after several related illnesses are considered and ruled out. The etiology of SLE is unclear, but hormonal factors, environmental toxins, infectious viruses, genetic predisposition, and certain medications have all been considered risk factors. Idiopathic SLE is seen predominantly in young women, with a female:male ratio of approximately 10:1. Each patient is unique and may suffer from a variety of signs and symptoms. The disease is highly unpredictable, and most patients experience flare-ups or fluctuations. The epidemiologic characteristics of medication-induced SLE (MI-SLE) are different from those of idiopathic SLE. Musculoskeletal symptoms predominate the clinical presentation of MI-SLE, while renal and central nervous system involvement is rare or absent. Moreover, a greater percentage of caucasian patients with no female predominance is evidenced in MI-SLE. Several medications can produce positive results on an antinuclear antibody test with or without evidence of clinical lupus. Hydralazine and procainamide are the most commonly recognized medications for inducing SLE. The onset of procainamide- and hydralazine-induced SLE occurs after 50 years of age, which is directly related to the age of the population using these medications. Estrogen-containing oral contraceptives and ibuprofen can exacerbate the symptoms of idiopathic SLE. Clinical judgment dictates the importance of careful patient monitoring and selection of therapy.

Autoantibody specificity in drug-induced lupus and neutrophil-mediated metabolism of lupus-inducing drugs

A long-term side effect of therapy with a variety of drugs is a syndrome resembling the idiopathic autoimmune disease, systemic lupus erythematosus. Essentially all patients with drug-induced lupus display autoantibodies to nuclear histone components whose specificity appears to be related to the higher order structure of histones existing in chromatin. IgG antibodies to H1 and the (H2A-H2B)-DNA complex were observed in most patients with lupus induced by procainamide, hydralazine, and quinidine, whereas the H3-H4 tetramer, comprising half the mass of the nucleosome core particle, was largely nonantigenic. IgM antibodies to (H2A-H2B)-containing chromatin subunits were common also. IgM reactivity was observed with the DNA-free H3-H4 tetramer and with H1, especially in hydralazine-induced lupus. These results suggest that IgM antihistone antibodies may result from autoimmunization with a nonnative form of chromatin, whereas IgG antibodies may be selected for reactivity with H1 and a native form of the (H2A-H2B)-DNA subunit of the nucleosome. The chemical basis for induction of autoimmunity by drugs is unclear because lupus-inducing drugs do not have a common structural feature or biological activity nor are they capable of specific reactions with histones, the principal target antigen. However, in the presence of activated neutrophils, procainamide is transformed metabolically to the cytotoxic procainamide-hydroxylamine. Mixing experiments and cell-free studies demonstrated that procainamide was cooxidized with H2O2 by myeloperoxidase released when neutrophils undergo the respiratory burst and degranulation reactions. Preliminary results indicate other lupus-inducing drugs are also biotransformed by this mechanism suggesting that a common denominator linking these drugs may be the capacity to be oxidized to reactive metabolites by the action of activated phagocytic cells.

Myocardial ischemia during vasodilator therapy in a canine model of pulmonary hypertension and coronary insufficiency

Pulmonary vasodilator therapy during increased right ventricular (RV) afterload and insufficient RV myocardial perfusion might further impair RV performance by lowering systemic and, thus, coronary perfusion pressure. This hypothesis was tested by initially inducing pulmonary hypertension (80% increase in resting pulmonary artery pressure by injection of autologous muscle) and subsequent right coronary artery stenosis (40% decrease in flow by external cuff occlusion) in eight open-chest dogs. Then the effects of nitroglycerin (5 micrograms.kg-1.min-1), prostaglandin E1 (0.2 microgram.kg-1.min-1), and hydralazine (mean 0.14 mg/kg) on global and regional (ultrasonic dimension technique) RV performance and coronary hemodynamics (electromagnetic flow probes) were determined. Following all three drugs, right coronary artery flow decreased by 40-65% (mean values) accompanied by severe regional myocardial dysfunction suggestive of ischemia (akinesis, systolic lengthening, and postsystolic shortening). Heart rates increased by 20-40%; aortic pressure decreased by 15-25%; and RV end-diastolic pressure remained unchanged. Despite similarly adverse effects on regional RV performance and comparable effects on heart rate, perfusion and filling pressures with all three drugs, RV systolic pressure, RV dP/dt, and pulmonary artery pressure during nitroglycerin and prostaglandin E1 remained unchanged, and stroke volume and pulmonary artery flow decreased, but they all increased or were maintained (stroke volume) during hydralazine. Gas exchange was not affected by any of the vasodilators. Thus, in this model of combined acute pulmonary hypertension and right coronary artery insufficiency, nitroglycerin, prostaglandin E1, and hydralazine elicited severe regional dysfunction suggestive of ischemia, probably related to concomitant increases in heart rate and decreases in coronary perfusion pressure. Despite such evidence of severe regional RV ischemia, hydralazine maintained global RV pump function. These results indicate 1) that in the presence of increased RV afterload and coronary insufficiency, reduction in coronary perfusion pressure during pulmonary vasodilator therapy may be deleterious, and 2) that even severe regional myocardial ischemia may not necessarily be accompanied by respective changes in global hemodynamics and thus may go undetected.

Autoantibodies to leucocyte antigens in hydralazine-associated nephritis

Clinical and laboratory findings and drug history were studied in 17 patients with suspected hydralazine-associated nephritis, five of whom only had renal disease, while twelve also had extrarenal manifestations. Renal biopsies revealed extracapillary proliferative or focal segmental proliferative glomerulonephritis in 10 patients, and tubulo-interstitial nephritis in five patients. Antinuclear antibody (ANA) was found in 16 patients, but none of the 14 patients tested had antibodies to DNA. Tests for antibodies to myeloperoxidase (anti-MPO) and antibodies to neutrophil cytoplasm antigen (ANCA) were performed by ELISA. Twelve of the 14 patients tested had anti-MPO; five of these 14 patients had ANCA, while one had borderline levels. These findings suggest that hydralazine facilitates the induction of a systemic disease with multiple autoantibody production.

Drug-related lupus

All physicians should be alerted to the many drugs and other agents that are associated with drug-related lupus, as there is an increasing number of such drugs. A wide range of immune responses and antibodies are being reported with this syndrome. A new concern is the perceived ability of new biologic treatments to induce these autoimmune phenomena. More in-depth studies of various environmental factors are providing new insights into possible mechanisms. These include the immune responses to the drugs, their metabolites, and drug-altered conjugates; bioactivation mechanisms of drug protein conjugation; the role of macrophages in antigen recognition and processing; and lastly, the important role of the acetylation of various drugs and the relationship to immunogenetic factors. Continued study of this human experimental model of lupus will help to clarify the etiology and mechanisms of systemic lupus erythematosus itself.

Drug-induced anti-histone autoantibodies display two patterns of reactivity with substructures of chromatin

Increasing evidence suggests that autoantibodies in the rheumatic diseases are a consequence of immune selection by self-material, but the nature of the in vivo immunogen is unknown. Insight into this problem may be obtained by measuring autoantibody binding to various forms of a target antigen. Antihistone antibodies arising as a side effect of therapy with various drugs offer an opportunity to explore this premise because many forms of histone have been characterized and adapted to ELISA formats. Two patterns of antibody reactivity were observed. All 21 patients with symptomatic procainamide-induced lupus and 7 of 12 patients with quinidine-induced lupus had IgG antibodies reacting predominantly with the (H2A-H2B)-DNA complex and with chromatin. In contrast, antibodies in 19 of 24 patients taking procainamide without accompanying lupus-like symptoms did not show any pattern. The second pattern was observed in 18/19 chlorpromazine-treated patients and 14/17 patients with hydralazine-induced lupus in which IgM antibodies displayed more reactivity with DNA-free histones than with the corresponding histone-DNA complexes and almost no binding to H1-stripped chromatin. Absorption studies were entirely consistent with these results. Thus, the two patterns of reactivity with nucleosomal components reflect the molecular substructure of chromatin, suggesting that two processes underlie antihistone antibody induction by drugs. In one, IgG autoantibodies appear to be elicited by chromatin, whereas in the other, autoimmune tolerance to native chromatin appears largely intact, and IgM antibodies may be driven by DNA-free histone.

A comparison of enalapril with hydralazine-isosorbide dinitrate in the treatment of chronic congestive heart failure

BACKGROUND

To define better the efficacy of vasodilator therapy in the treatment of chronic congestive heart failure, we compared the effects of hydralazine and isosorbide dinitrate with those of enalapril in 804 men receiving digoxin and diuretic therapy for heart failure. The patients were randomly assigned in a double-blind manner to receive 20 mg of enalapril daily or 300 mg of hydralazine plus 160 mg of isosorbide dinitrate daily. The latter regimen was identical to that used with a similar patient population in the effective-treatment arm of our previous Vasodilator-Heart Failure Trial.

RESULTS

Mortality after two years was significantly lower in the enalapril arm (18 percent) than in the hydralazine-isosorbide dinitrate arm (25 percent) (P = 0.016; reduction in mortality, 28.0 percent), and overall mortality tended to be lower (P = 0.08). The lower mortality in the enalapril arm was attributable to a reduction in the incidence of sudden death, and this beneficial effect was more prominent in patients with less severe symptoms (New York Heart Association class I or II). In contrast, body oxygen consumption at peak exercise was increased only by hydralazine-isosorbide dinitrate treatment (P less than 0.05), and left ventricular ejection fraction, which increased with both regimens during the 2 years after randomization, increased more (P less than 0.05) during the first 13 weeks in the hydralazine-isosorbide dinitrate group.

CONCLUSIONS

The similar two-year mortality in the hydralazine-isosorbide dinitrate arms in our previous Vasodilator-Heart Failure Trial (26 percent) and in the present trial (25 percent), as compared with that in the placebo arm in the previous trial, (34 percent) and the further survival benefit with enalapril in the present trial (18 percent) strengthen the conclusion that vasodilator therapy should be included in the standard treatment for heart failure. The different effects of the two regimens (enalapril and hydralazine-isosorbide dinitrate) on mortality and physiologic end points suggest that the profile of effects might be enhanced if the regimens were used in combination.

Should continuous hydralazine infusions be utilized in severe pregnancy-induced hypertension?

Intravenous hydralazine therapy in severe preeclampsia-eclampsia may be administered by either continuous intravenous infusion or intermittent bolus therapy. We studied the hemodynamic effects of continuous intravenous hydralazine infusion in seven patients with severe pregnancy-induced hypertension. The starting infusion dose was 5 mg/hr and was increased every 15 to 20 minutes by 1 to 2 mg/hr to obtain a 20% reduction in mean arterial blood pressure. The initial mean systolic and diastolic blood pressures were 208.3 +/- 24.8 and 124.3 +/- 11.6 mmHg, respectively. The comparable mean levels following hydralazine therapy was 144 +/- 13.6 and 87 +/- 11.6 mmHg. This decline was obtained at a mean hydralazine dose of 16.04 +/- 3.65 mg/hr. Despite an increase in cardiac output, the rapid uncontrolled decline in blood pressure resulted in five of the seven patients developing fetal distress requiring cesarean delivery. If hydralazine therapy is to be used in severe preeclampsia-eclampsia, we advocate avoidance of continuous intravenous therapy.

Risk of serious morbidity associated with hydralazine versus methyldopa treatment in hypertensive patients

The medical records of patients presenting to the Hammersmith Hospital hypertension clinic between 1971 and 1981 were examined to determine presenting clinical data, treatment regimes, and both cardiovascular and non cardiovascular mortality and morbidity. When compared with 1004 patients receiving treatment other than hydralazine 310 patients on hydralazine had a significantly higher risk of developing renal disease (RR = 2.71) in men, and severe weight loss in women (RR = 3.06). Renal disease risk also tended to be high in women on hydralazine (RR = 1.95) compared with all other treatments, but this was not statistically significant and could be explained by poorer renal function and significantly higher untreated blood pressure in the hydralazine treated group at presentation. The 422 patients who were treated with methyldopa but not hydralazine had similar risk factors for cardiovascular disease compared with a group of 167 who received hydralazine but not methyldopa. Comparisons of event rates failed to find significant differences in morbidity or mortality between these two groups. The age adjusted male mortality was 14/1000 patient years on hydralazine and 12/1000 on methyldopa and 13/1000 and 6/1000 years for women respectively. There was no evidence of an increased risk of either renal disease (RR = 0.3 in men, RR = 0.3 in women) on hydralazine or weight loss (RR = 0.7 in men, RR = 1.6 in women), with similar presenting data. Systemic lupus erythematosus was a rare complication (2 of 314) of treatment with hydralazine.