Drug Profile

Do Not Use: This is an irrational combination of ingredients and can lead to high blood potassium levels.

This product, a combination of amiloride (MIDAMOR) and hydrochlorothiazide (ESIDRIX, HYDRODIURIL, MICROZIDE), is used to treat high blood pressure (hypertension). Older adults should not use drugs that contain a fixed combination of amiloride and hydrochlorothiazide. Thiazides with amiloride may produce high potassium in the blood and substantial sodium depletion.[2]  

There are good reasons not to use any fixed-combination drug for high blood pressure. A single drug is often enough to control high blood pressure. There is no reason to put yourself at extra risk by taking drugs you do not need. 

The Food and Drug Administration (FDA)-approved product label for this drug carries the following warning in boldface type:

This fixed combination drug is not indicated for the initial therapy of edema or hypertension except in individuals in whom the development of hypokalemia cannot be risked.[3] 

First-line treatment for high blood pressure

If you have high blood pressure, the best way to reduce or eliminate your need for medication is by improving your diet, losing weight, exercising, and decreasing your salt and alcohol intake. Mild hypertension can be controlled by proper nutrition and exercise. If these measures do not lower your blood pressure enough and you need medication, hydrochlorothiazide, a water pill, is the drug of choice, starting with a low dose of 12.5 milligrams daily. It also costs less than other blood-pressure drugs. 

There is growing evidence that thiazide diuretics, such as hydrochlorothiazide, significantly decrease the rate of bone mineral loss in both men and women because they reduce the amount of calcium lost in the urine.[4] Research now suggests that thiazide diuretics may protect against hip fracture.[5] 

If your high blood pressure is more severe, and hydrochlorothiazide alone does not control it, another family of high blood pressure-lowering drugs may be added to your treatment. In this case, your doctor would prescribe the hydrochlorothiazide and the second drug separately, with the dose of each drug adjusted to meet your needs, rather than using a product that combines the drug in a fixed combination. 

Whatever drugs you take for high blood pressure, once your blood pressure has been normal for a year or more, a cautious decrease in dose and renewed attention to nondrug treatment may be worth trying, according to The Medical Letter on Drugs and Therapeutics.[6] 

An editorial in the British Medical Journal (BMJ) stated:

Treatment of hypertension is part of preventive medicine and like all preventive strategies, its progress should be regularly reviewed by whoever initiates it. Many problems could be avoided by not starting antihypertensive treatment until after prolonged observation. ... Patients should no longer be told that treatment is necessarily for life: the possibility of reducing or stopping treatment should be mentioned at the outset.[7]

The May 2012 issue of Worst Pills, Best Pills News highlighted a recent BMJ study indicating that patients taking several types of commonly used antihypertensive medications are at increased risk of developing gout, a type of arthritis.

The BMJ study also showed that a small number of other antihypertensive drugs appear to have the opposite effect, decreasing the risk of gout.

All patients should be informed of the risk of gout with diuretics, beta-blockers, angiotensin-converting enzyme inhibitors (ACE inhibitors) and non-lorsartan angiotensin II receptor blockers (ARBs) when starting these medications or whenever the dose of the medications is increased [8].

The April 2013 issue of Worst Pills, Best Pills News discusses another recent BMJ study. This study suggests that an increased risk of acute kidney injury (AKI) is associated with combining nonsteroidal anti-inflammatory drugs (NSAIDs) with two antihypertensive drugs: a diuretic plus either an ACE inhibitor or an ARB. The risk was found to be highest during the first 30 days of starting an NSAID in patients who also are already taking a diuretic plus an ACE inhibitor or an ARB.

The study found that patients currently using a triple-therapy combination — a diuretic, an ACE inhibitor or an ARB, and an NSAID — have a 31 percent greater risk of developing AKI compared with current users of a diuretic plus an ACE inhibitor or an ARB without an NSAID.[9]

Regulatory actions surrounding hydrochlorothiazide

2011: In March, the FDA issued the following warning concerning the use of hydrochlorothiazide products:

Hydrochlorothiazide, a sulfonamide, can cause an idiosyncratic reaction, resulting in acute transient myopia and acute angle-closure glaucoma. Symptoms include acute onset of decreased visual acuity or ocular pain and typically occur within hours to weeks of drug initiation. Untreated acute angle-closure glaucoma can lead to permanent vision loss. The primary treatment is to discontinue hydrochlorothiazide as rapidly as possible. Prompt medical or surgical treatments may need to be considered if the intraocular pressure remains uncontrolled. Risk factors for developing acute angle-closure glaucoma may include a history of sulfonamide or penicillin allergy.[10]