Thiazide diuretic prescription and electrolyte abnormalities in primary care

Abstract

AimsThiazide diuretics have a number of well-documented metabolic adverse effects. The aim of this study was to estimate the frequency of hyponatraemia and hypokalaemia amongst patients taking a thiazide diuretic in primary care. MethodsA computerized search of the electronic prescribing and laboratory records of six U K general practices was performed. Of the 32 218 adult patients identified, 3773 had received at least one prescription for a thiazide between the years 1990 and 2002. ResultsDetailed prescribing data were available for 2942 patients of whom 951 (32.3%) had a recorded check of their electrolytes. One hundred and ninety-six (20.6%) had a sodium and/or potassium concentration below the normal range. The sodium distribution had a negative skew ( − 1.8) and in 130 (13.7%) patients was within the hyponatraemic range. Hypokalaemia was less common, occurring in 79 (8.5%) patients. Hyponatraemia was significantly associated with increased age; the odds ratio for developing hyponatraemia in patients over 70 years was 3.87 compared with those of ≤ 70 years. Hypokalaemia was significantly associated with increased thiazide dose. ConclusionsPrescription of a thiazide diuretic in primary care is associated with a high frequency of hyponatraemia and hypokalaemia. Thiazides should be prescribed at low dose and the risk of hyponatraemia, especially in the elderly, should be considered and monitored for when prescribing these agents.

Serum sodium abnormality profile in hospitalized elderly patients in a tertiary care centre from north India: a cross sectional observational study

“…In recent studies varying proportions of the patient have been associated with multiple etiologies of hyponatremia. In comparison to this, in a study by Clayton et al 75% of the patients of hyponatremia had multiple etiologies 15,19 while in study by Nzerue et al only 10.9% of the patients had multiple etiological factors which nearly supports our study. 20 In a study on elderly patients on hypernatremia by NEAL A et al found that out of 162 patients of hypernatremia, 72 (44%) patients had three or more causal factors leading to hypernatremia which was supporting our study, though no.…”

“…In a study by Clyton J A et al they had found no direct correlation between hyponatremia and hypertension but correlation between hypertension with age and use of diuretics is evident. 15 Most of the patients had neurological symptoms in both groups of sodium disorder. These findings were consistent with NaureenTareen, David Martin et al in their research in "sodium disorders in elderly'' in which they had described that depending on the magnitude and rate of development of hyponatremia, the clinical presentation may range from asymptomatic to overt central nervous system symptoms, such as lethargy, confusion, seizures, coma and death.…”

Hyponatremia Independent of Osteoporosis is Associated with Fracture Occurrence

“…Thiazide diuretics are widely used as firstline agents in the treatment of hypertension but are complicated in up to 14% of subjects by hyponatremia (21,22). Among subjects aged 65 years and older resident in a nationally representative sample of U.S. nursing homes, thiazide use was associated with increased fracture risk over 1 year of follow-up (23).…”

Acquired Long QT Interval: A Case Series of Multifactorial QT Prolongation

“…23 The use of diuretics is known to produce the above-mentioned electrolyte disturbances and thereby indirectly prolong the QT interval. Notably, the severity of hypokalemia is dose-dependent in the setting of thiazide diuretics 19,24 and is accentuated with the combination of diuretics and other medications, such as digitalis, where hypokalemia may aggravate digitalis-induced arrhythmias. 19 …”