Losartan Substitute for Losartan HCTZ, is It OK?

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Losartan and losartan HCTZ are prescription antihypertensive medications. Both drugs are angiotensin II antagonists. These two are usually taken once a day and can be in combination therapy with other antihypertensive drug such as amlodepine. Losartan HCT

Angiotensin II antagonists or angiotensin II blockers like losartan potassium work by preventing the protein angiotensin from binding to the blood vessel.  Angiotensin causes constriction within the vein that causes hypertension. With the use of ARBs agent (angiotensin receptor blockers) like losartan, blood vessels are dilated making the blood circulation free flowing and blood pressure is diminished.

Losartan potassium is a prescription antihypertensive drug.  It can be given in single or in combination with other antihypertensive medication. Amlodepine, a calcium antagonist is the usual combination with losartan. These two drugs are not generally taken at a time though. Prescribers usually give losartan in the morning then amlodepine in the evening for control of hypertension.  However, if the condition cannot be controlled by such combination, losartan plain is usually switched to losartan with the HCTZ or hydrochlorothiazide. 

Dispensing error may happen and sometimes patients try cheaper alternatives. In the case of losartan and losartan HCTZ, won’t there be any problem if losartan plain is taken instead of a losartan HCTZ?

Losartan facts

Bepsar (Nabiqasim), Cozaar (Merck Sharp & Dohme) and Lifezar (Therapharma) are some popular tradenames of losartan potassium. It is generally indicated for hypertension that can be given alone or with other antihypertensive drugs.

Losartan potassum is available in 50 and 100mg tablet. It can be taken in full or empty stomach and usually given in 50mg strength during the initial treatment. Depending on the body’s response, or if the patient has liver or kidney problem, losartan’s maintenance dosing can range to 25, 50 to 100mg strength. It can be taken once or twice a day.

  • Contraindications

Losartan is contraindicated in pregnancy.

  • Special precautions

Losartan should be used in precaution for breast feeding mothers, children, elderly people and for individuals with liver and kidney problems.

  • Side effects

Losartan may cause allergic symptoms like cough, respiratory congestion and utricaria. It can cause dizziness, fatigue, UTI, diarrhea or constipation. Hyperkalemia, cardiac arrythmia and hypotension are also cited.

  • Drug interactions

Phenobarbital and ketoconazolecan reduce the effect of losartan. Cimetidine on the other hand, can increase the effect of losartan.  Potassium supplements, potassium sparing diuretics like amiloride and canrenone may increase risk of hyperkalemia with losartan potassium.  Losartan with NSAIDs (e.g. indomethacin, piroxicam, and mefenamic) may increase liver impairment especially in elderly people.

Hydrocholorothiazide facts

HCTZ or hydrochorothiazide is a thiazide diuretic. In combination with losartan potassium, its strength is generally 12.5mg. But used alone, hydrocholorothiazide can be taken in 25 to 100mg potency.

Some brand names of hydrochlorothiazide in single form are Diuzid (Hizon), Hytaz (Therapharma) and Hydrax (Lloyd). HCTZ with losartan brandnames include Hextan Plus (Pasteur Pharma), Getzar Plus (Hizon) and Accuzide (Pfizer).

Hydrochlorothiazide is generally taken once a day in the morning and should be taken in full stomach. As a diuretic, HCTZ is indicated for edema linked to heart failure and in liver or kidney disorders. It works by enhancing urine production, expelling the excess salt and water from the body.

In hypertension, blood pressure is also reduced whenever fluids are released from the system. Medical specialist would compare hypertension to a full-blown balloon that needs to be dealt carefully to prevent it from popping. By liberating the air slowly and bit by bit, this balloon won’t go off – the same case with high blood pressure and urinating.

Hydrochlorothiazide in combination with losartan is usually given once a day in the morning. Alone, HCTZ is indicated for hypertension 25 to 50mg daily.

  • Contraindications

Hydrocholorothiazide is not recommended in pregnancy and breastfeeding mothers. Not only that HCTZ is in category C concerning pregnancy which may be risky for the fetus, this medication may also reduce milk production.

  • Precautions

Hydrocholorothiazide is to be used in precaution in elderly people, individuals who have liver or kidney problems and those with severe heart failure. 

  • Side effects

Some side effects of HCTZ are fluid loss, muscle cramps, weakness and thirst. There are also reported allergic reactions such as rash, swelling and breathing difficulty. Headache, stomach pains and dizziness can also be experienced.

  • Drug interactions

The effect of HCTZ may be decreased by cholesthyramine and colestipol – both cholesterol lowering drugs. HCTZ can potentiate the effects of antidiabetic medications and may increase arrythmias therefore it should not be taken with digoxin.  Care should be exercised upon using hydrochlorothiazidewith other antihypertensive drugs to avoid hypotension. Finally, HCTZ can also increase lithium levels.

Losartan potassium for losartan potassium with HCTZ, is it OK?

In 2008, a hypertensive patient bought ten pieces of losartan plain instead of losartan with hydrochlorothiazide. She took this wrong medication with her amlodepine and aspirin for ten days. It was during the next refill when the pharmacy aid found out about the dispensing error. Fortunately, nothing bad happened to the patient. 

Since, the patient was also taking another antihypertensive drug which was amlodepine; losartan plain may have not created a problem. More to this, losartan even without the hydrocholorothiazide is still an antihypertensive medication.

Image by the author

Losartan HCTZ is more potent than the ordinary losartan because of its diuretic content. But, as cited, hypertension can be controlled. With lifestyle improvement (proper diet and exercise) along with the losartan-amlodepine combination maintenance, highblood pressure can be managed. Physicians tend to adjust the medication into a lesser degree when blood pressure begins to drop. 

Losartan plain for losartan HCTZ may seem OK at least for awhile, when there are no other alternatives. However, cases vary and it is not wise when a patient decides to change his antihypertensive drug without the advice of his doctor.

Losartan HCTZ for the plain losartan?

The real danger is when a patient accidentally took a losartan with a hydrochlorothiazide instead of a losartan plain. As losartan HCTZ is more powerful than the plain losartan, hypotension or a drop of blood pressure can be immediate. This won’t also be good for the patient if he is already taking other diuretics as loss of potassium and other electrolytes can harm the body.

© Phoenix Montoya @ September 5, 2012


  1. http://mims.com/
  2. Medications and Mothers’ Milk by Thomas W. Hale Ph.D.

1 comment

Francois Hagnere
Posted on Sep 5, 2012