Syndrome of inappropriate antidiuretic hormone-induced hyponatremia associated with amiodarone

Severe hyponatremia due to trimethoprim-sulfamethoxazole-induced SIADH

Hyponatremia, a serum sodium level of <135 mEq/L, is the most common electrolyte abnormality occurring in 5%–35% of hospitalized patients. It is a predictor of increased morbidity and mortality. Diuretics, psychotropic, and antiepileptic drugs are commonly implicated in drug-induced hyponatremia. Trimethoprim-sulfamethoxazole and spironolactone are two commonly prescribed drugs; unfortunately, most providers are unfamiliar with these two drugs causing hyponatremia. Simultaneous use of trimethoprim-sulfamethoxazole and spironolactone can cause serious drug interactions that increase the risk of hyponatremia, hyperkalemia, and overall mortality. Despite recommendations to avoid using these two drugs concurrently, many healthcare providers continue to prescribe them together. We report a case of an elderly female with severe hyponatremia caused by trimethoprim-sulfamethoxazole superimposed on a chronic but stable mild hyponatremia.

Amiodarone-Induced Hyponatremia in An Elderly Patient: A Rare Case Report

Amiodarone is an antiarrhythmic drug belonging to Vaughan-Williams Class III with additional Class IV effects, which is known to cause many adverse drug reactions (ADRs) necessitating close monitoring. In about 20% of patients, their therapy is discontinued due to adverse effects such as hepatic impairment, thyroid dysfunction, and several pulmonary complications. Although dyselectrolytemia is a common adverse reaction reported with many cardiac medications, the incidence of hyponatremia associated with amiodarone intake is not reported widely in the literature.We are reporting a case of a 73-year-old female patient, with hypertension and ischemic heart disease (IHD) receiving oral amiodarone, presenting with severe hyponatremia, requiring recurrent hospitalization. Amiodarone was found to be responsible after evaluating for the possible causes of hyponatremia.As the incidence of amiodarone-associated hyponatremia is unknown, and not many cases are reported, this case report serves to sensitize the clinician to consider amiodarone-induced hyponatremia as one of the differential diagnoses in cases of unexplained hyponatremia.

Altered Mental Status and Hyponatremia After 20 Hours of Amiodarone Therapy

A 66-year-old woman with no relevant medical history presented at the emergency department with new-onset atrial fibrillation. We initiated intravenous amiodarone therapy. At 20 hours, the patient experienced severe neurologic symptoms, hyponatremia, and syndrome of inappropriate antidiuretic hormone. We discontinued amiodarone, infused saline solution, and restricted the patient's fluid intake. She recovered in 3 days. This case illustrates that amiodarone-induced syndrome of inappropriate antidiuretic hormone with hyponatremia can occur far earlier than expected during acute amiodarone therapy.

Amiodarone-induced Hyponatremia: A Case Report and a Review of the Literature

Amiodarone is a widely used medication for controlling various types of cardiac arrhythmias. Nonetheless, it carries several known adverse effects that may preclude its use or necessitate discontinuation. Hyponatremia resulting from amiodarone is rarely reported, and its incidence is unknown. We present a case of severe hyponatremia secondary to amiodarone therapy and a review of the literature.

Employment of vasopressin receptor antagonists in management of hyponatraemia and volume overload in some clinical conditions

WHAT IS KNOWN AND OBJECTIVE

Hyponatraemia, the most common electrolyte imbalance occurring in hospitalized subjects, is usually classified as hypovolaemic, euvolaemic or hypervolaemic. Hyponatraemia is a predictor of death among subjects with chronic heart failure and cirrhosis. The inappropriate secretion of the antidiuretic hormone (AVP) seems to be of pivotal importance in the decline of serum sodium concentration in these clinical conditions. The objective of this review was to summarize recent progress in management of hyponatraemia in SIADH, cirrhosis and heart failure.

METHODS

Literature searches were conducted on the topics of hyponatraemia and vasopressin receptor antagonists, using PubMed, pharmaceutical company websites and news reports. The information was evaluated for relevance and quality, critically assessed and summarized.

RESULTS AND DISCUSSION

The initial treatment of severe hyponatraemia is directed towards the prevention or management of neurological manifestations and consists of an intravenous infusion of hypertonic saline. Fluid restriction is indicated in oedematous states. Diuretics alone or in combination with other specific drugs remain the main strategy in the management of volume overload in heart failure. In resistant cases, ultrafiltration can lead to effective removal of isotonic fluid preventing new episodes of decompensation; however, aquapheresis is associated with increased costs and other limits. In several trials, the efficacy of vasopressin receptor antagonists in euvolaemic patients (inappropriate antidiuretic hormone secretion) or in hypervolaemic hyponatraemia (chronic heart failure, cirrhosis) has been evaluated. It was found that vaptans, which promote aquaresis, were superior to a placebo in raising and maintaining serum sodium concentrations in these subjects.

WHAT IS NEW AND CONCLUSIONS

Combined with conventional therapy, vasopressin receptor antagonists (AVP-R antagonists) are able to increase the excretion of electrolyte-free water and the sodium concentration. Further studies are needed to assess efficacious outcomes of aquaresis compared with aquapheresis and with conventional therapy.

Amiodarone induced hyponatremia masquerading as syndrome of inappropriate antidiuretic hormone secretion by anaplastic carcinoma of prostate

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is one of the most common causes of hyponatremia. The usual causes are malignancies, central nervous system, pulmonary disorders, and drugs. Amiodarone is a broad spectrum antiarrhythmic agent widely used in the management of arrhythmias. The different side effects include thyroid dysfunction, visual disturbances, pulmonary infiltrates, ataxia, cardiac conduction abnormalities, drug interactions, corneal microdeposits, skin rashes, and gastrointestinal disturbances. SIADH is a rare but lethal side effect of amiodarone. We describe a 62-year-old male who was suffering from advanced prostatic malignancy, taking amiodarone for underlying heart disease. He developed SIADH which was initially thought to be paraneoplastic in etiology, but later histopathology refuted that. This case emphasizes the importance of detailed drug history and the role of immunohistochemistry in establishing the diagnosis and management of hyponatremia due to SIADH.

Hyponatremia - a rare but serious complication of amiodarone: a case report and review of the literature

Introduction

Hyponatremia secondary to the syndrome of inappropriate antidiuretic hormone secretion (SIADH) during amiodarone therapy is a rare but potentially lethal adverse effect. We report a case of severe hyponatremia associated with amiodarone, and discuss its clinical implications.

Case Report

An 84-year-old Caucasian man with a past medical history of hypertension and diabetes was admitted to the hospital with a non-ST elevation myocardial infarction. He underwent coronary artery bypass graft and developed atrial fibrillation on postoperative day 2. A loading dose of amiodarone followed by a maintenance dose was started. The serum sodium level was 136 mmol/l at discharge and subsequently decreased to 105 mmol/l 11 days later, at which time the patient represented with altered mental status. The diagnosis of SIADH was made based on euvolemic hypoosmotic hyponatremia, lack of any other medication known to cause SIADH and urine that was less than maximally dilute. The serum sodium increased gradually to 123 mmol/l after 36 h of treatment with hypertonic saline, demeclocycline and fluid restriction.

Conclusion

SIADH-induced hyponatremia associated with amiodarone occurs rarely. Since severe hyponatremia is associated with significant neurological damage and mortality, clinicians should carefully monitor serum sodium during amiodarone therapy.

Syndrome of inappropriate antidiuretic hormone in association with amiodarone therapy: a case report and review of literature

BACKGROUND

Amiodarone is a class III antiarrhythmic agent that is widely used in the treatment of a variety of arrhythmias. Several different systemic side effects are reported after use of this medication. In this article, we report a case that had developed syndrome of inappropriate antidiuretic hormone (SIADH) after starting treatment with this agent.

CASE REPORT

The patient is a 66-year-old male with past medical history of hypertension, hyperlipidemia, coronary artery disease, and class III New York Heart Association congestive heart failure who presented with monomorphic nonsustained ventricular tachycardia. A loading dose of amiodarone followed by maintenance dose was started. Baseline serum sodium of 138 mmol/L on admission decreased to 119 mmol/L by day 7, and a diagnosis of SIADH was made. The patient was not taking any other medication known to cause SIADH, nor had any such comorbidity to explain it. Serum sodium increased to 133 and 138 mmol/L, respectively, after 16 and 33 days from discontinuation of amiodarone.

CONCLUSION

SIADH is a rare but serious side effect of amiodarone and practicing physicians should be aware of this complication, particularly after loading dose of the medication.

Amiodarone-related hyponatremia: rare but potentially lethal

Amiodarone is a one of the most commonly used antiarrhythmic drug with efficacy in both supraventricular and ventricular tachycardia. Hepatic, pulmonary, and thyroid adverse effect profiles of this drug are well described and mandate a close follow-up. We report a case of amiodarone-related hyponatremia, which is one of the rarest side effects associated with this medication and our case was unlike other previous case reports because severity of symptoms required hemodialysis for correction of hyponatremia despite trying dose reduction strategy.

New agents for managing hyponatremia in hospitalized patients

PURPOSE

An overview of hyponatremia is provided, including its pathophysiology, clinical manifestations, signs and symptoms, and treatment, particularly with arginine vasopressin (AVP)-receptor antagonists.

SUMMARY

Hyponatremia (generally defined as a serum sodium concentration of <135 meq/L) is one of the most common electrolyte disorders in hospitalized and clinic patients. It may be caused by a number of conditions, including infections, heart disease, surgery, malignancy, and medication use. Clinical signs and symptoms such as hallucinations, lethargy, weakness, bradycardia, respiratory depression, seizures, coma, and death have been reported. Conventional treatment consists of fluid restriction and administration of hypertonic saline and pharmacologic agents, such as demeclocycline, lithium carbonate, and urea. These treatment options are often of limited effectiveness or difficult for patients to tolerate. AVP promotes the reabsorption of water in the renal collecting ducts by activation of V(2) receptors, resulting in water retention and dilution of serum solutes. The AVP-receptor antagonists, conivaptan, lixivaptan, and tolvaptan, are being studied for the treatment of hyponatremia. Conivaptan has been shown in clinical trials to increase free-water excretion and safely normalize serum sodium concentrations in patients with hyponatremia and is well tolerated. Also in clinical trials, lixivaptan and tolvaptan have safely improved serum sodium concentrations in patients with hyponatremia.

CONCLUSION

Hyponatremia is a serious health condition for which treatment should be carefully performed. As new agents for treating hyponatremia, AVP-receptor antagonists have demonstrated efficacy and safety in clinical trials and may serve as significant improvements in the current treatment options for managing this disorder.