Thiazide diuretics
BMJ 2024; 384 doi: https://doi.org/10.1136/bmj-2023-075174 (Published 05 February 2024) Cite this as: BMJ 2024;384:e075174
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Dear Editor,
I would like to thank the authors for this helpful overview on Thiazide and Thiazide-like diuretics.
I note the case in question which is a very common occurrence for both General Practitioners and Physicians alike: “A 56 year old woman with hypertension and no other comorbidities develops swollen ankles while taking amlodipine. She has normal renal function and you are considering adding a thiazide or thiazide-like diuretic. What issues do you need to consider and what do you need to discuss with the patient?” [1]
The most appropriate initial treatment is not actually starting a diuretic but switching the Amlodipine to an ACEI/ARB for her hypertension control (or to reduce the dose of Amlodipine and add in an ACEI). Furthermore, adding a thiazide diuretic may actually be of limited benefit in treating the ankle swelling. [2]
The incidence of Calcium Channel Blockers, particularly dihydropyridine ones like Amlodipine, causing leg oedema is reported at between 5-70% (depending on the cohort of patients assessed, dose used, duration of treatment, comorbidities of the patients etc). A useful teaching number is 1 in 5 develop some degree of ankle swelling. This is higher (and more severe) particularly in those with older age, reduced mobility and in women (although not clear why in the latter). [3,4,5]
It is usually best to discontinue medications potentially causing (significant) side-effects than initiating another to treat the side-effects.
One further teaching point: It is not always just the Thiazide, but the Thiazide in combination with other medications/factors which result in Hyponatraemia (which can occur at any time interval after initiation). [6]
Yours Sincerely,
References:
1. Thiazide diuretics
BMJ 2024; 384 doi: https://doi.org/10.1136/bmj-2023-075174
2. Managing peripheral oedema caused by calcium channel blockers
NHS Specialist Pharmacy Service (September 2022)
https://www.sps.nhs.uk/articles/managing-peripheral-oedema-caused-by-cal...
3. Amlodipine, Enalapril, and Dependent Leg Edema in Essential Hypertension
Hypertension. 2000;35:621–625. https://doi.org/10.1161/01.HYP.35.2.621
4. Leg edema with (S)-amlodipine vs conventional amlodipine given in triple therapy for hypertension: a randomized double blind controlled clinical trial
BMC Cardiovasc Disord. 2016; 16(1): 168. doi: 10.1186/s12872-016-0350-z
5. Amlodipine-Induced Pedal Edema and Its Relation to Other Variables in Patients at a Tertiary Level Hospital of Kathmandu, Nepal.
J Pharm Technol. 2019 Apr; 35(2): 51–55. doi: 10.1177/8755122518809005
6. Risk of thiazide-induced hyponatremia in patients with hypertension.
Am J Med. 2011;124(11):1064. https://doi.org/10.1016/j.amjmed.2011.06.031
Competing interests: No competing interests
Dear Editor,
Hypertensive people on Amlodepine often develop Ankle Oedema.
Here, often the cause of Oedema is not Fluid Overload or Overt Right Ventricle dysfunction.
Amlodepine causes more vasodilatation of the afferent arterioles than of the efferent arterioles.
Often Simple salt restriction and leg elevation will relieve Oedema.
An alternative will be to replace Amlodepine with Cilnidipine or Benedipine if Calcium Channel Blockers are desired.
Another alternative is to use ARBs(Angiotensin Receptor Blockers).
Physician do not often use Moxinidine, but can be used instead of Amlodepine.
Diuretics have following disadvantages:
Electrolyte imbalance,
Increased Uric Acid level,
Increased Creatinine,
Postural Hypotension.
- Arvind Joshi,
MBBS MD FCGP FAMS FICP.
Competing interests: No competing interests
Re: Thiazide diuretics
Dear Editor
There was an interesting omission in this useful article, namely the longstanding advice from the Medicines and Healthcare products Regulatory Authority to UK prescribers from 2018 titled "Hydrochlorothiazide: risk of non-melanoma skin cancer, particularly in long-term use" (https://www.gov.uk/drug-safety-update/hydrochlorothiazide-risk-of-non-me...).
Indeed, although the risk is small, documented advice to patients about this risk is one of the multitudinous "safety" checks undertaken by the Care Quality Commission in its inspections of general practices in the UK.
Yours sincerely
Competing interests: No competing interests