Determinants of thiazide induced hyponatraemia in pre-exposed elderly - a controlled experiment

Completed

Conditions: Thiazide induced hyponatraemia
Metabolic disorders
Nutritional, Metabolic, Endocrine

Registration Number: ISRCTN38727701

Lead Sponsor: Academic Medical Centre (AMC) (The Netherlands)

Brief Summary: Not available

Detailed Description: Not available

Recruitment & Eligibility

Status: Completed

Sex: Not specified

Target Recruitment: 36

Inclusion Criteria

1. Age 60 - 80 years
2. Previously admitted with thiazide-induced hyponatraemia
3. Patients must be willing and medically able to discontinue anti-hypertensive therapy six weeks before the study and for the duration of the study
4. Patients must be willing to be admitted for 24 hours and must be medically able to take the study medication
5. Patients must be willing to give informed consent

Exclusion Criteria

1. Other causes for hyponatraemia (e.g. heart failure, pulmonary disease, medication associated with hyponatraemia)
2. Renal dysfunction (estimated clearance less than 50 ml/min according to Cockroft-Gault)
3. Liver cirrhosis
4. Heart failure
5. Medication: antipressiva (Selective Serotonin Reuptake Inhibitors [SSRI?s]), antiepileptica, prednisone, Non-Steroidal Anti-Inflammatory Drugs (NSAID?s), opioids, other diuretics (e.g. lasix, burinex, chloorthalidon, dytac)
6. Allergy for sulphonamide derivates
7. Therapy resistant hypertension (Blood Pressure [BP] greater than 140/90 mmHg while using three or more anti-hypertensive drugs)

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Effect of a single oral dose hydrochloorthiazide 50 mg intake on the serum and urine sodium, serum ADH, prostaglandin E2 and urinary aquaporin-2 excretion in elderly patients (aged 60 - 80 years) with previous thiazide-induced hyponatraemia (sodium less than 125 mmol/l) without another cause for their hyponatraemia and matched controls receiving a thiazide diuretic without hyponatraemia. <br><br>Urinary hydrochlorothiazide concentrations are measured to analyse differences in thiazide metabolism. The response to ADH will be assessed by expression of AVPR2 in a cell-culture and determine its activity by measurement of cyclic Adenosine Monophospahte (cAMP).<br><br>Outcomes will be measured at baseline (n = 0) and after 4, 8 and 24 hours.

Secondary Outcome Measures

Name	Time	Method
To identify (elderly) patients who are at risk of thiazide induced hyponatraemia.<br><br>Outcomes will be measured at baseline (n = 0) and after 4, 8 and 24 hours.