Repurposing the cardiac glycoside digoxin to stimulate myelin regeneration in chemically-induced and immune-mediated mouse models of multiple sclerosis

Multiple sclerosis (MS) is a central nervous system (CNS) autoimmune disease characterized by inflammation, demyelination, and neurodegeneration. The ideal MS therapy would both specifically inhibit the underlying autoimmune response and promote repair/regeneration of myelin as well as maintenance of axonal integrity. Currently approved MS therapies consist of non-specific immunosuppressive molecules/antibodies which block activation or CNS homing of autoreactive T cells, but there are no approved therapies for stimulation of remyelination nor maintenance of axonal integrity. In an effort to repurpose an FDA-approved medication for myelin repair, we chose to examine the effectiveness of digoxin, a cardiac glycoside (Na+ /K+ ATPase inhibitor), originally identified as pro-myelinating in an in vitro screen. We found that digoxin regulated multiple genes in oligodendrocyte progenitor cells (OPCs) essential for oligodendrocyte (OL) differentiation in vitro, promoted OL differentiation both in vitro and in vivo in female naïve C57BL/6J (B6) mice, and stimulated recovery of myelinated axons in B6 mice following demyelination in the corpus callosum induced by cuprizone and spinal cord demyelination induced by lysophosphatidylcholine (LPC), respectively. More relevant to treatment of MS, we show that digoxin treatment of mice with established MOG35-55 -induced Th1/Th17-mediated chronic EAE combined with tolerance induced by the i.v. infusion of biodegradable poly(lactide-co-glycolide) nanoparticles coupled with MOG35-55 (PLG-MOG35-55 ) completely ameliorated clinical disease symptoms and stimulated recovery of OL lineage cell numbers. These findings provide critical pre-clinical evidence supporting future clinical trials of myelin-specific tolerance with myelin repair/regeneration drugs, such as digoxin, in MS patients.

Cardiotonic Steroids and the Sodium Trade Balance: New Insights into Trade-Off Mechanisms Mediated by the Na⁺/K⁺-ATPase

In 1972 Neal Bricker presented the "trade-off" hypothesis in which he detailed the role of physiological adaptation processes in mediating some of the pathophysiology associated with declines in renal function. In the late 1990's Xie and Askari published seminal studies indicating that the Na⁺/K⁺-ATPase (NKA) was not only an ion pump, but also a signal transducer that interacts with several signaling partners. Since this discovery, numerous studies from multiple laboratories have shown that the NKA is a central player in mediating some of these long-term "trade-offs" of the physiological adaptation processes which Bricker originally proposed in the 1970's. In fact, NKA ligands such as cardiotonic steroids (CTS), have been shown to signal through NKA, and consequently been implicated in mediating both adaptive and maladaptive responses to volume overload such as fibrosis and oxidative stress. In this review we will emphasize the role the NKA plays in this "trade-off" with respect to CTS signaling and its implication in inflammation and fibrosis in target organs including the heart, kidney, and vasculature. As inflammation and fibrosis exhibit key roles in the pathogenesis of a number of clinical disorders such as chronic kidney disease, heart failure, atherosclerosis, obesity, preeclampsia, and aging, this review will also highlight the role of newly discovered NKA signaling partners in mediating some of these conditions.

Cardiac glycosides use and the risk and mortality of cancer; systematic review and meta-analysis of observational studies

BACKGROUND

Cardiac glycosides (CGs) including digitalis, digoxin and digitoxin are used in the treatment of congestive heart failure and atrial fibrillation. Pre-clinical studies have investigated the anti-neoplastic properties of CGs since 1960s. Epidemiological studies concerning the association between CGs use and cancer risk yielded inconsistent results. We have performed a systematic review and meta-analysis to summarize the effects of CGs on cancer risk and mortality.

METHODS

PubMed, Scopus, Cochrane library, Medline and Web of Knowledge were searched for identifying relevant studies. Summary relative risks (RR) and 95% confidence intervals (CI) were calculated using random-effects model.

RESULTS

We included 14 case-control studies and 15 cohort studies published between 1976 and 2016 including 13 cancer types. Twenty-four studies reported the association between CGs and cancer risk and six reported the association between CGs and mortality of cancer patients. Using CGs was associated with a higher risk of breast cancer (RR = 1.330, 95% CI: 1.247-1.419). Subgroup analysis showed that using CGs increased the risk of ER+ve breast cancer but not ER-ve. Using CGs wasn't associated with prostate cancer risk (RR = 1.015, 95% CI: 0.868-1.87). However, CGs decreased the risk in long term users and showed a protective role in decreasing the risk of advanced stages. CGs use was associated with increased all-cause mortality (HR = 1.35, 95% CI: 1.248-1.46) but not cancer-specific mortality (HR = 1.075, 95% CI: 0.968-1.194).

CONCLUSION

The anti-tumor activity of CGs observed in pre-clinical studies requires high concentrations which can't be normally tolerated in humans. However, the estrogen-like activity of CGs could be responsible for increasing the risk of certain types of tumors.

The Associations of Atrial Fibrillation With the Risks of Incident Invasive Breast and Colorectal Cancer

Atrial fibrillation (AF) is a common arrhythmia that poses a significant risk of stroke. Cross-sectional and case-control studies have shown evidence of associations between AF and breast or colorectal cancer, but there have been no longitudinal studies in which this has been assessed. We prospectively examined a cohort of 93,676 postmenopausal women enrolled in the Women's Health Initiative from 1994 to 1998 to determine whether there are relationships between baseline AF and the development of invasive breast or colorectal cancer. The prevalence of self-reported physician diagnosis of AF at baseline was 5.1%. Over approximately 15 years of follow-up, the incidence of invasive breast cancer was 5.7%, and the incidence of colorectal cancer was 1.6%. Adjusted hazard ratios and 95% confidence intervals were obtained using Cox proportional hazards models. We found no significant association between AF and incident colorectal cancer, but we did see a 19% excess risk of invasive breast cancer among those with AF (adjusted hazard ratio (HR) = 1.19, 95% confidence interval (CI): 1.03, 1.38). Additional adjustment for baseline use of cardiac glycosides attenuated the association between AF and invasive breast cancer (HR = 1.01, 95% CI: 0.85, 1.20). Cardiac glycoside use was strongly associated with incident invasive breast cancer (HR = 1.68, 95% CI: 1.33, 2.12) independent of AF and other confounders. Mechanisms of the associations among breast cancer, AF, and cardiac glycosides need further investigation.

Treatment characteristics in elderly

The pharmacodynamics and pharmacokinetics of medications, their therapeutic and toxic effects are age dependant. In the treatment of old people polypharmacy is widely used. The most common results of polypharmacy are increased adverse drug reactions, drug-drug interactions. In this study the use of different medications at the Departments of General Medicine and Cardiology (Tbilisi Republic Hospital) was analyzed. The case histories (1995, 2000 and 2005) of 1708 patients were studied. It was found that in 2005 the number of 60 years and older patients has doubled comparably with 1995, but the number of 24-44 years old patients remained almost the same. The complication rate was higher in elderly as compared with younger patients. It was found that in treatment of elderly population hypotensive drugs, diuretics and cardiac glycosides are used excessively. In the case of excess use of antihypertension medications there is a big risk of developing arterial hypotension. In old people it may lead to orthostatic hypotension, in youth - to dizziness. The frequent use of diuretics in old people may be accompanied with dehydration and risk of developing thromb formation. Hyponatraemia, hypokalaemia, hypomagnesemia lead to heart rhythm disturbances and risk of glycoside intoxication. In old people the therapeutical doses of diuretics depend not only on their biological activity, but also on the ability of their absorption from the gastrointestinal tract, on the organism's resistance and in the case of repeated intake on their cumulation quality and extraction.

Difficulties in maintaining potassium homeostasis in patients with heart failure

Potassium (K) concentration plays a significant role in cell metabolism and membrane excitability. The imbalance of serum potassium is important because it can lead to life-threatening events. Potassium balance may be lost both through the neurohormonal mechanisms involved in cardiovascular diseases and through the drugs used in the treatment of this illness. Avoiding both hypo- and hyperkalemia is beneficial in several cardiovascular diseases, especially heart failure. Electrolyte abnormalities are frequently seen complications in subjects with heart failure. Malignant ventricular arrhythmias and sudden cardiac death are particularly feared complications in K+ instability.

Unexpectedly Dangerous Escargot Stew: Oleandrin Poisoning through the Alimentary Chain*

A female, aged 43 and a male, aged 66, experienced gastrointestinal and cardiovascular symptoms after a meal including snail stew. Twelve hours after the ingestion, they presented with nausea, vomiting, diarrhea, and cardiovascular symptoms typical of acute toxic digoxin ingestion and were hospitalized. The man's electrocardiogram was altered, and the woman's was normal. Serum digoxin levels, measured on a Roche COBAS Integra 800 with the Roche On-Line Digoxin reagent, were 1.14 and 1.00 nmol/L, respectively. Potassium levels were normal in both patients. The serum digoxin concentration decreased on the second day, and symptoms resolved on the third day with patients fully recovered (i.e., reversion to a normal sinus rhythm). Cardiac-glycoside-like intoxication symptoms follow the ingestion of leaves or flowers of Nerium oleander. The consumed snails were suspected to be responsible for the intoxication. In the homogenized snail tissue, the concentration expressed in digoxin equivalents was 0.282 nmol/g. The presence of oleandrin and oleandrigenin in the snails was confirmed by liquid chromatography-tandem mass spectrometry analysis, which was performed on a ionic-trap Finnigan LXQ instrument using an electrospray ionization interface. High-pressure liquid chromatographic separation was performed on a C18 column with a gradient of methanol/water. An extract of oleander leaves was used as reference.

Drug therapy of paroxysmal atrial fibrillation in the elderly over 75 years old

OBJECTIVE

To investigate the effectiveness and safety of various agents on paroxysmal atrial fibrillation in the elderly over 75 years old.

METHODS

Totally 264 in-patients (75-91 years old, 185 males and 79 females) with atrial fibrillation history of less than 7 days were enrolled in this study. A total of 611 atrial fibrillation episodes were recorded, but 130 episodes (22.3%) of atrial fibrillation were auto-converted to sinus rhythm. The rest 481 episodes of atrial fibrillation were divided into six groups based on the drug used.

RESULTS

The cardioversion ratio of atrial fibrillation were 9.5%, 46.9%, 71.7%, 55.9%, 32.7%, and 73.6% in control, cedilanid, amiodarone, propafenone, verapamil, and quinidine groups, respectively. Ventricular rate control were 5.4%, 83.6%, 84.9%, 77.9%, 78.8%, and 11.3% in those groups, respectively. The total effective rates of amiodarone and cedilanid groups were the highest. When the ventricular rate was controlled to below 90 bpm, the patients would almost complain of no discomfort. No severe side-effect was observed in each group.

CONCLUSION

Amiodarone and cedilanid may be the proper drugs for the treatment of paroxysmal atrial fibrillation in the elderly. The above antiarrhythmics in each therapeutic group were relatively safe and effective.

Cardiovascular pharmacotherapeutic considerations during pregnancy and lactation

Cardiovascular drugs are often used in pregnancy for the treatment of maternal and fetal conditions. Mothers could also require continued postpartum drug therapy. Most cardiovascular drugs taken by pregnant women can cross the placenta and therefore expose the developing embryo and fetus to their pharmacologic and teratogenic effects. These effects are influenced by the intrinsic pharmacokinetic properties of a given drug as well as by the complex physiological changes occurring during pregnancy. Many drugs are also transferred into human milk and therefore can potentially have adverse effects on the nursing infant. This 2-part article summarizes some of the available literature concerning the risks and benefits of using various cardiovascular drugs and drug classes during pregnancy and lactation. Included in the discussion are cardiac glycosides, antiarrhythmic drugs, drugs used to treat both acute and chronic hypertension, cholesterol-lowering agents, anticoagulants, thrombolytics, and antiplatelet drugs.

[Manifestation and prevention of adverse drug reactions (ADR) in the pharmacotherapy of cardiovascular diseases]

OBJECTIVES

Cardiovascular drugs are the most often prescribed drug class in Germany. The objective of this study is to analyze the adverse drug reaction (ADR) profiles of these drugs and to identify some targets for prevention of ADR.

METHOD

Since 1997 specially trained medical staff members of five Pharmacovigilance Centers in Germany prospectively screened all hospital admissions at the departments of internal medicine of five large teaching hospitals. ADR leading to hospital admission were registered and reported. Especially ADR caused by cardiovascular drugs and all factors, which could have been important for their occurrence were analyzed.

RESULTS

559 of 2270 (24.6%) registered ADR cases were related to cardiovascular drugs. The drugs most frequently related to ADR were angiotensin inhibitors (17.9%), digitalis (17.3%), calcium channel blockers (13.9%), beta blockers (12.8%), and diuretics (12.2%). The most often observed ADR were arrhythmias (27.1%), syncopes and blood pressure dysregulations (25.1%), gastrointestinal symptoms (12.4%), and metabolic disorders (10.2%). 72% of patients were older than 65 years. Older patients were on a significantly higher number of drugs (6.2 +/- 2.4 vs 5.5 +/- 3.2; p < 0.001) than the younger ones. Furthermore, they were hospitalized significantly longer (13.2 +/- 9.9 vs 15.3 +/- 9.3 days; p < 0.01). Eleven patients (2%) died because of ADR due to cardiovascular drugs.

CONCLUSIONS

Cardiovascular drugs are frequently used. They are prescribed mainly to older patients. Often observed ADR can be prevented effectively by considering their indication, by a clear definition of the therapeutic target, by a dose adjustment to the individual clinical parameters of the patient and by regular control investigations. The large number of drug-induced rhythm disorders--in particular bradycardia--show that extraordinary attention should be paid to rhythm-affecting drugs. The detailed instruction of the patient about therapeutic aims, risks and a concrete guideline for the therapy/drug handling is generally necessary.

Standards of laboratory practice: cardiac drug monitoring. National Academy of Clinical Biochemistry

In this Standard of Laboratory Practice we recommend guidelines for therapeutic monitoring of cardiac drugs. Cardiac drugs are primarily used for treatment of angina, arrhythmias, and congestive heart failure. Digoxin, used in congestive heart failure, is widely prescribed and therapeutically monitored. Monitoring and use of antiarrhythmics such as disopyramide and lidocaine have been steadily declining. Immunoassay techniques are currently the most popular methods for measuring cardiac drugs. Several reasons make measurement of cardiac drugs in serum important: their narrow therapeutic index, similarity in clinical complications and presentation of under- and overmedicated patients, need for dosage adjustments, and confirmation of patient compliance. Monitoring may also be necessary in other circumstances, such as assessment of acetylator phenotypes. We present recommendations for measuring digoxin, quinidine, procainamide (and N-acetylprocainamide), lidocaine, and flecainide. We discuss guidelines for measuring unbound digoxin in the presence of an antidote (Fab fragments), for characterizing the impact of digoxin-like immunoreactive factor (DLIF) and other cross-reactants on immunoassays, and for moni-toring the unbound (free fraction) of drugs that bind to alpha1-acid glycoprotein. We also discuss logistic, clinical, hospital, and laboratory practice guidelines needed for implementation of a successful therapeutic drug monitoring service for cardiac drugs.

Oleander toxicity: an examination of human and animal toxic exposures

The oleander is an attractive and hardy shrub that thrives in tropical and subtropical regions. The common pink oleander, Nerium oleander, and the yellow oleander, Thevetia peruviana, are the principle oleander representatives of the family Apocynaceae. Oleanders contain within their tissues cardenolides that are capable of exerting positive inotropic effects on the hearts of animals and humans. The cardiotonic properties of oleanders have been exploited therapeutically and as an instrument of suicide since antiquity. The basis for the physiological action of the oleander cardenolides is similar to that of the classic digitalis glycosides, i.e. inhibition of plasmalemma Na+,K+ ATPase. Differences in toxicity and extracardiac effects exist between the oleander and digitalis cardenolides, however. Toxic exposures of humans and wildlife to oleander cardenolides occur with regularity throughout geographic regions where these plants grow. The human mortality associated with oleander ingestion is generally very low, even in cases of intentional consumption (suicide attempts). Experimental animal models have been successfully utilized to evaluate various treatment protocols designed to manage toxic oleander exposures. The data reviewed here indicate that small children and domestic livestock are at increased risk of oleander poisoning. Both experimental and established therapeutic measures involved in detoxification are discussed.

Heart failure and electrolyte disturbances

Electrolyte abnormalities are a frequent and potentially hazardous complication in patients with heart failure. This may be due to the pathophysiological alterations seen in the heart failure state leading to neurohumoral activation (stimulation of the renin-angiotensin-aldosterone system, sympathoadrenergic stimulation), and due to the complications of therapy with diuretics, cardiac glycosides or ACE inhibitors. Patients with heart failure may exhibit hyponatremia due to a decrease in water excretion, which may be related to the enhanced release of both angiotensin and vasopressin and can be exaggerated by diuretic therapy. Along with potassium and calcium, magnesium influences cardiovascular function. Magnesium and potassium deficiencies play an important role in the development of cardiac arrhythmias. Magnesium is essential for the maintenance of intracellular potassium concentration. Although there are conflicting data regarding the prevalence of hypomagnesemia in patients with chronic heart failure (the values range from 7-37%), multiple studies have documented lower magnesium concentrations in patients with heart failure than in normal controls. As magnesium and potassium are mainly intracellular ions, measurements in serum or plasma are of limited value to assess magnesium status. There was no correlation between the intracellular electrolyte content and the electrolyte levels in plasma, either for mononuclear cells or erythrocytes or for myocardial and skeletal muscle. Loop diuretics (e.g. furosemide) are supposed to cause a substantial loss of both magnesium and potassium in the plasma and intracellular space. The potassium-sparing diuretics amiloride and triamterene are reported to also exert magnesium-sparing effects. Recently, ACE inhibitors have been documented to have important magnesium-conserving actions, possibly via their effect on glomerular filtration. Hyperkalemia, secondary to the use of ACE inhibitors in patients with heart failure, is well documented. Digoxin directly limits the renal tubular reabsorption of magnesium, therefore increasing magnesium excretion. Low magnesium and potassium concentrations increase cardiac glycoside toxicity. In contrast, elevated levels of magnesium decrease the sensitivity of human myocardium to antiarrhythmogenic actions of cardiac glycosides, without affecting maximally developed tension. Moreover, magnesium increases binding affinity of cardiac glycosides to the receptor. The antiarrhythmic action of magnesium is suspected to be mediated by a reduced sensitivity to electrophysiological changes induced by Ca2+, thus indicating Ca2+ antagonistic properties of magnesium. Magnesium deficiency has also been implicated in sudden death, notably in patients with congestive heart failure. Therefore, when treating congestive heart failure, one must consider how to prevent depletion of electrolytes or how to replete potassium and magnesium in deficiency states.

Pharmacologic treatment of heart failure

An increased understanding of the pathophysiologic changes underlying CHF, advanced monitoring technology, and a wider array of drug therapy have improved the prognosis of patients with this disorder. These advances allow for greater individualization of therapy, improve patient compliance, and lower the incidence of undesirable side effects. Of course, with the increase in complexity of treatment choices comes the need for more knowledgeable practitioners who can select the most appropriate therapeutic approach. All practitioners also must make every effort to educate the patients about their disease, treatments, and necessary lifestyle changes so that optimal benefits can be realized.

Risks of agranulocytosis and aplastic anemia in relation to the use of cardiovascular drugs: The International Agranulocytosis and Aplastic Anemia Study

The risks of agranulocytosis and aplastic anemia in relation to the use of cardiovascular drugs were estimated in a population-based case-control study conducted in Israel and Europe (total population, 23 million). Cardiovascular drug use in the week before onset of illness was compared between 270 patients hospitalized with agranulocytosis and 1870 hospitalized control subjects. Propranolol (relative risk, 2.5), dipyridamole (3.8), digoxin (2.5), and acetyldigoxin (9.9) were significantly associated with agranulocytosis. The excess risks attributable to these drugs ranged from one to three cases per 10 million persons exposed for up to 1 week. Increased risks were also observed for cinepazide (used by six cases and no control subjects), procainamide (7, 1), and aprindine (5, 1); based on crude relative risk estimates, the excess risks for the latter two drugs were approximately three per million persons exposed for up to 1 week. The use of cardiovascular drugs in a 5-month period ending 1 month before hospital admission was compared between 152 patients with aplastic anemia and 2180 control subjects. Furosemide was the only significantly associated drug (relative risk, 3.1); the excess risk attributable to any exposure in a 5-month interval was 1.7 per million.

[Endogenous digitalis-like substances and cardiac glycosides: facts and hypotheses]

The review presents the data on endogenous digitalis-like substances the effects of which are imitated by administered cardiac glycosides. It is suggested that the individual differences in the responses of patients to cardiac glycosides, a great range of doses of the drugs causing intoxication as well as the absence of a close correlation between the occurrence of therapeutic and toxic effects and blood plasma glycoside concentration are related to the change of the level of endogenous digitalis-like substances in the organism. The further study of the chemical structure of digitalis-like substances and the mechanism of their secretion opens up new possibilities for practical medicine.

Cardiac glycoside toxicity resulting from cough linctus abuse

Proprietry cough medicines are often abused by drug addicts as they are freely available and, in many instances, contain narcotic substances. A variety of other compounds are present in these products, including compounds structurally related to the commonly prescribed cardiac glycosides. We report a case in which severe cardiac glycoside toxicity resulted from the abuse of such a preparation.

The role of intracellular Ca ions in the therapeutic and toxic effects of cardiac glycosides and catecholamines

Many inotropic maneuvers act by increasing the intracellular calcium concentration [( Ca2+]i). The present report illustrates this with respect to the positive inotropic effects of cardiac glycosides and catecholamines. It is shown that the increased contractility produced by cardiac glycosides is accompanied by an increase in intracellular Na concentration and, furthermore, that the relationship between contraction and Na is very steep. This steep dependence, which may result from a Na-Ca exchange which exchanges several Na ions per Ca, means that maneuvers that have only small effects on Na will have significant effects on contraction. Cardiac glycosides also produce abnormal pacemaker activity and cardiac arrhythmias. These originate from a transient inward current activated by oscillations of [Ca2+]i, which result from spontaneous oscillatory release of Ca ions from the sarcoplasmic reticulum. The local anesthetic group of antiarrhythmic agents abolishes the transient inward current. Catecholamines also increase systolic [Ca2+]i and, in high enough concentrations, can produce oscillations of [Ca2+]i. This tendency of glycosides and catecholamines to produce arrhythmogenic oscillations of [Ca2+]i is a major limitation to their use. Therefore, inotropic agents that act by means other than increasing [Ca2+]i may be of great efficacy.

[Effect of cardiac glycosides on whole body potassium concentration in circulatory insufficiency]

Variation of potassium levels produced by cardiac glycosides was assessed in patients with 1st- to 3d-stage circulatory insufficiency, by means of 40K radioactivity measurement in a low radioactivity background chamber. Total group figures demonstrated that total body potassium levels increased with the improvement of the patients' clinical condition. Total body potassium decreased in patients showing signs of cardiac glycoside intoxication. The analysis of the data with reference to pre-and post-treatment baseline tissue potassium concentrations, as compared to the desired level, showed tissue potassium to normalize under the effect of cardiac glycosides in cases of initially abnormal values, and to decrease irrespective of the initial values in cases of cardiac glycoside intoxication.

[Autoimmunity induced by drugs. Immunological characteristics and etiopathogenic hypotheses]

Drug-induced autoimmune diseases have two immunological peculiarities. Firstly, some autoantibodies are present, which are virtually never seen in spontaneous human diseases and may be regarded as specific. This applies to antimitochondria antibody type 3 (anti M3) in the lupus-like syndrome caused by Venocuran, to antimitochondria antibody type 6 (anti M6) in iproniazide-induced hepatitis, to anti-insulin antibody found after treatment with methimazole, and to anti liver/kidney microsome antibody type 2 (anti LKM2) associated with hepatitis induced by tielinic acid. Secondly, a search for other autoantibodies shows that the immune disorder is much more limited than in spontaneous autoimmune diseases. Thus, contrary to myasthenia and idiopathic autoimmune haemolytic anaemia, we never found autoantibodies specifically directed against the thyroid, the stomach or the adrenal gland during treatment with D-penicillamine and alpha-methyldopa. Only some hypotheses may account for these peculiarities. Cross-reaction between drug and autoantigen may occur, but the fact that the antigen-antibody reaction is not inhibited by the drug or its metabolites does not support this explanation. Much more attractive is the "T-cell bypass" theory, according to which autoreacting suppressor T-cells are circumvented by helper T-cells stimulated by the drug-modified autoantigen. In this case, the autoimmune reaction would indicate to which body substance the drug is bound, thus making it immunostimulant, and not a structural similarity between the drug and the autoantigen.

Medication problems among outpatients. A study with emphasis on the elderly

When patients ascribe adverse symptoms to their medications, the medical care process can be affected. To investigate how often medical outpatients link various adverse symptoms with their medications and to learn what actions they take in response, 299 randomly selected medical outpatients were interviewed. Thirty percent of the subjects identified at least one medication as causing an undesirable symptom. Subjects 65 years or older attributed a lower mean number of adverse symptoms to their medications than did younger subjects. Subjects rarely reported modifying their medication regimens due to adverse symptoms, a finding supported by multiple regression analysis. Approximately one in four subjects did not discuss their symptoms with their providers. These results have important implications for medical care in general, and for the elderly in particular.

[Acute fatal non-occlusive intestinal ischemia during treatment with a cardiotonic glucoside]

After presenting the case of a 70 year old woman who presented a massive mesenteric infarction as a result of non-occlusive intestinal ischaemia ( NOII ), the authors review the principal features of this particular form of intestinal ischaemia. This condition is seen principally in elderly people with a syndrome of low cardiac output, resulting in marked mesenteric vasoconstriction. It is a complication of either severe decompensated heart disease treated with digitaloids or to a state of hypovolaemic or septic shock. The diagnosis of NOII should be suggested by the combination of abdominal signs with a state of shock and/or treated heart disease. The diagnosis is confirmed by selective mesenteric arteriography which reveals a patent but spastic vessel. The treatment is initially medical, consisting of the correction of haemodynamic disturbances and the in situ injection of vasodilator products, which may need to be completed by a surgical operation. However, the prognosis of NOII remains serious, particularly because of the frequent delay in making the diagnosis.

Therapeutic range of cardiac glycosides

The narrow therapeutic range of cardiac glycosides continually challenges chemists to synthetize new derivatives with improved therapeutic properties. One of the best investigated semi-synthetic glycosides is 16 alpha-gitoxin. Compared to ouabain and gitoxin, it produces positive inotropic effects on the isolated guinea-pig heart in a wider range of concentrations and causes less pronounced rhythmic disturbances. These results were confirmed by electrophysiological investigations in isolated fibres of the canine myocardium and of the Purkinje system, by investigations in the anaesthetized cat and dog and in healthy volunteers. The effects of various semi-synthetic compounds (e.g. actodigin, ASI-222) are described and possibilities to trigger these effects are discussed. Of some significance seem to be differences in the structure of the (Na+ + K+)-ATPase system of different tissues, e.g. the working muscle and the Purkinje system of the heart, as well as differences due to the formation and dissociation of the glycoside-enzyme complex. The significance of K+, Ca2+ and of several pharmacokinetic parameters (e.g. the volume of distribution) for these reactions are briefly discussed.

[Drug incompatibility in the aged]

Geriatric patients often have several diseases so that in the acute phase the doctor has to treat with many drugs simultaneously. Elderly persons are more vulnerable to drug effects, both therapeutic and adverse. Physiological and pathological changes with aging influence geriatric drug therapy. Pharmacokinetic differences are generally consistent with age differences in renal and liver function, body composition, tissue perfusions, protein and cellular binding. The present paper gives some examples (glycosides, anticoagulants) of drug therapy and adverse reactions.

[Indications and contraindications for therapy with cardiac glycosides]

Today glycosides have 3 indications: manifest and chronic cardiac insufficiency, arrhythmia absoluta and paroxysmal supraventricular tachycardia. Glycosides are no longer important in the therapy of acute cardiac insufficiency. There are also absolute and relative contraindications which should be recognized; in coronary heart disease glycosides should only be used if there is really a latent of manifest cardiac insufficiency.

[Hemodynamic examinations concerning the effects of cardiac glycosides in hypertrophic obstructive cardiomyopathy (HOCM)]

Due to fundamental considerations and especially after Braunwald's et al. (1962 (4)) examinations of 5 patients with severe hypertrophic obstructive cardiomyopathy (HOCM) with 0.5-0.75 mg of Ouabain, cardiac glycosides in cases of this disease are to be regarded as contraindicated. Own examinations (right and left-heart catheterizations, monoplane cineangiography of the left ventricle, determination of the cardiac output, and the ejection fraction (EF) were performed in 10 patients with HOCM of different stages. Applying the usual dosage of 0.25-0.375 mg of strophanthin, different hemodynamic effects were observed in discrete forms. In cases with a higher severity, the observations of Braunwald et al. could actually be confirmed. The left ventricular systolic pressure gradients were increased, but cardiac output, left ventricular enddiastolic pressure, pulmonary pressure and resistance, and also arterial pressure and peripheral resistance behaved differently. EF increased slightly. The right infundibular gradients were decreased with one exception, or resp., they were unchanged. Obviously, HOCM reacts especially unfavourably with so-called left-ventricular cavity obliteration. The main importance might belong to the behaviour of the free lumen of the left ventricle. In regard of the principally reserved attitude towards the cardiac glycoside therapy in HOCM, no change has occurred. Only in patients with atrial fibrillation and a rapid heart rate, a therapy trial could be considered, if necessary in combination with beta-blocking agents or calcium antagonists under hemodynamic control. In cases of HOCM with serious obstruction and signs of cardiac failure and inadequate affecting by calcium antagonists, an early surgical intervention should be executed.

Adverse effects of cardiovascular drug therapy on the fetus and neonate

Possible adverse effects of cardiovascular medications on the fetus and the neonate have been reviewed. The major classes discussed were diuretics, antihypertensives, antiarrhythmics, cardiac glycosides, and anticoagulants. The recommendations given must not be considered definitive because they are based on flawed or incomplete information. It is to be hoped that further investigation will improve this situation and will also improve our understanding of the ways in which these drugs act.

[Pseudo-(venocuran-)lupus--a minor episode in the history of medicine]

Pseudolupus is a syndrome characterized by recurrent fever arthralgia, myalgia, involvement of lung and heart, high sedimentation rate, leukocytosis and lymphopenia. The diagnosis is established by the presence of circulating antimitochondrial antibodies. In 1975 it was found that the disease was due to prolonged treatment with Venocuran, a drug against venous disorders composed of phenopyrazone (pyrazolone derivative), horse-chestnut extract, and Miroton (glycosides extracted from white squill [Urginea maritima], convallaria, oleander and adonis). The drug was then withdrawn. No new cases have come to our attention since then. 15 patients with severe pseudolupus known to us in 1975 have now been followed up. In 6 of the patients all symptoms disappeared within weeks or a few months after withdrawal of the drug. However, the other 9 patients had at least 1 and often 2--3 relapses in the following months to years. In some patients, symptoms remained as long as 4--5 years. Antimitochondrial antibodies persisted in 4 patients for more than 3 years and in 1 patient are still detectable now. The pathomechanism of pseudolupus has not been elucidated.