Losartan-Hydrochlorothiazide

Medically Reviewed by Dr. Harshi Dhingra, M.D.

Last Reviewed: Sep 27, 2023

Warnings

Losartan Hydrochlorothiazide Risks, Warnings, and Complications

Losartan hydrochlorothiazide can cause or worsen health problems in some people. Talk to your doctor or pharmacist about taking other medications to control high blood pressure if you are at increased risk of adverse reactions or complications from this combination therapy.

FETAL AND MATERNAL RISK: Losartan hydrochlorothiazide can be harmful to an unborn baby if a pregnant woman takes it during the second and third trimesters of pregnancy. This drug can cause reduced fetal renal function. The disordered renal function can increase the risk of congenital abnormalities and death. In addition, in patients receiving thiazide therapy, the drug can cross the placenta and cause fetal or neonatal jaundice and thrombocytopenia (low platelet count). Due to the significant fetal risk associated with losartan hydrochlorothiazide, this medication is not prescribed to pregnant women. Tell your doctor if you are pregnant before starting treatment with this combination medicine. Stop taking losartan hydrochlorothiazide and call your doctor immediately if you become pregnant while on this medicine.
LOW BLOOD PRESSURE: Taking losartan hydrochlorothiazide can result in hypotension (low blood pressure). Hypotension occurs more commonly in people who are dehydrated or have fluid or electrolyte imbalance and those taking high doses of the medicine. Low blood pressure is more likely to occur when you first start taking losartan hydrochlorothiazide and after dose titrated upward (dose increase). Closely monitor blood pressure at home. Tell your doctor if you have diarrhea, vomiting, or excessive sweating while on this drug. Call your doctor if you develop dizziness, lightheadedness, or tiredness during treatment.
KIDNEY PROBLEMS: This combination contains a diuretic (water pill) hydrochlorothiazide, which affects the renin-angiotensin system and can cause acute renal failure (acute kidney failure) in some patients, such as patients with volume depletion, chronic kidney disease, renal artery stenosis, or severe congestive heart failure. Keep all your laboratory and medical appointments while on this medicine. Your provider will monitor renal function periodically and may temporarily stop or discontinue treatment if you develop compromised renal function.
ALLERGIC REACTIONS: Rarely, losartan hydrochlorothiazide can cause a serious allergic reaction. The risk of this happening is higher in people with a history of allergies or bronchial asthma and those with allergies to sulfa drugs or penicillin. Call your doctor immediately or seek emergency medical care if you develop signs and symptoms of an allergic reaction, such as swelling, difficulty breathing, or skin rash.
FLUID OR ELECTROLYTE IMBALANCE: Taking losartan hydrochlorothiazide can lead to hypokalemia (low potassium), hyponatremia (low sodium), and hypomagnesemia (low magnesium). However, in some people, this medication can increase serum potassium. Your provider will closely monitor serum potassium and other electrolytes during treatment with this combination of medications.
METABOLIC AND ELECTROLYTE EFFECTS: Hydrochlorothiazide is a thiazide diuretic (water pill). It can alter glucose tolerance, increase cholesterol and triglyceride levels, cause increased urinary calcium excretion and decreased serum calcium, and lead to hyperuricemia (increased serum uric acid) and gout attacks. However, losartan decreases serum uric acid, and the combination of losartan hydrochlorothiazide is therefore, less likely to increase uric acid levels. Your healthcare provider will order laboratory tests during treatment with this combination drug to keep an eye on these parameters. Keep all your lab and medical appointments.
EYE PROBLEMS: Hydrochlorothiazide is a sulfonamide and it can cause serious eye problems such as acute transient myopia and acute angle-closure glaucoma. The risk of this happening is higher in people with a known history of allergic reaction to sulfonamides or penicillins. Tell your doctor immediately if you develop symptoms such as a sudden decrease in vision or eye pain. This can happen within hours or several weeks after starting the medicine. If left untreated, acute angle-closure glaucoma can lead to permanent loss of vision. If you develop eye problems, your provider will stop hydrochlorothiazide as soon as possible. You may need additional medical or surgical treatments.
SYSTEMIC LUPUS ERYTHEMATOSUS: Taking thiazide diuretics such as hydrochlorothiazide can cause or worsen an autoimmune condition called systemic lupus erythematosus. Give your doctor a complete medical history before starting treatment with this medication.

Precautions Before Starting Losartan Hydrochlorothiazide

Tell your doctor if you have ever had allergic reactions to losartan, hydrochlorothiazide, any of the active or inactive ingredients in losartan hydrochlorothiazide tablets, other angiotensin II receptor antagonists, other diuretics, sulfa drugs, penicillin, or any other medications. Your pharmacy can give you a list of ingredients.

Give your doctor and pharmacist a complete list of your medications, including prescription medications, over-the-counter medicines, vitamins, supplements, and herbal products. This can help avoid dangerous drug interactions between your medications.

Give your healthcare professional a complete medical history. Losartan hydrochlorothiazide may not be right for people with certain medical conditions such as kidney disease, liver disease, heart failure, high cholesterol, diabetes, asthma, gout, glaucoma, or lupus (SLE).

Tell your doctor if you are pregnant, could be pregnant, plan to get pregnant, or are nursing an infant with breast milk.

Precautions During Use of Losartan Hydrochlorothiazide

Keep all your medical and lab appointments while on this medication. Your healthcare provider may want to keep an eye on kidney function and electrolytes during treatment.

Maintain a log of your blood pressure readings at home and bring it to your appointments. Your provider may adjust your dose of losartan hydrochlorothiazide based on your response.

Try to take losartan hydrochlorothiazide at least 4 hours before bedtime. This medication can make you urinate more, and taking it later in the day can lead to nighttime awakenings to urinate.

Losartan hydrochlorothiazide can cause dizziness, lightheadedness, and drowsiness, especially when you first start taking it and after dose adjustments. Do not drive, operate machinery, or do any other hazardous activity until you know how it affects you. You should know that alcohol can make these side effects worse.

Taking this combination therapy can cause dizziness, lightheadedness, and fainting when going from a sitting or lying position to standing. Get out of bed slowly to avoid falls.

Stay well hydrated during treatment with losartan hydrochlorothiazide. Call your doctor if you develop vomiting, diarrhea, excessive sweating, or inability to drink enough fluids. Tell your doctor without delay if you develop dizziness, weakness, and low blood pressure.

Hydrochlorothiazide can increase the sensitivity of your skin to sunlight and increase your risk of melanoma and non-melanoma skin cancer. Avoid unnecessary sun exposure and wear sunscreen, sunglasses, and protective clothing when outdoors.

If you are taking cholesterol-lowering medications such as cholestyramine or colestipol, make sure you take it away from hydrochlorothiazide (at least 1 hour before or 4 hours after your blood pressure medicine).

If you have diabetes (high blood sugar) and are taking medications to treat it, talk to your doctor about how often you need to monitor your blood sugar levels. Losartan hydrochlorothiazide can cause changes in glucose tolerance, and your provider may need to adjust your medicine dosages.

Do not stop taking losartan hydrochlorothiazide without talking to your doctor. Stopping this medication suddenly can lead to dangerously high blood pressure and increase your risk of heart attack and stroke.

Tell your doctor immediately if you become pregnant while on losartan hydrochlorothiazide.

Tell all your healthcare providers you are on losartan hydrochlorothiazide before any surgery or medical tests, including dental procedures.

Losartan Hydrochlorothiazide Drug Interactions

Certain other drugs can affect how losartan hydrochlorothiazide works. Possible drug interactions with other medicines can increase the risk of severe adverse reactions. The following medications can have interactions with losartan hydrochlorothiazide:

Aliskiren (Tekturna, in Tekturna HCT, in Tekamlo, in Amturnide) in people with diabetes
Other medications used to treat high blood pressure, such as angiotensin-converting enzyme (ACE) inhibitors, for example, benazepril (Lotensin, in Lotrel), enalapril (Vasotec), captopril (Capoten, in Capozide), lisinopril (in Prinzide, in Zestoretic), fosinopril, moexipril (Univasc, in Uniretic), ramipril (Altace), quinapril (Accupril, in Accuretic, in Quinaretic), perindopril (Aceon), and trandolapril (Mavik, in Tarka)
Other diuretics or water pills, including potassium-sparing diuretics such as spironolactone (Aldactone, in Aldactazide), amiloride (Midamor), and triamterene (Dyrenium, in Maxzide, in Dyazide)
Aspirin and other nonsteroidal anti-inflammatory medications (NSAIDs) such as ibuprofen (Motrin, Advil) and naproxen (Naprosyn, Aleve)
Pain medications such as selective COX-2 inhibitors, for example, celecoxib (Celebrex)
Antifungal drugs like fluconazole (Diflucan)
Psychiatric medications such as lithium (Lithobid, Eskalith)
Antiepileptic drugs such as phenobarbital and secobarbital (Seconal)
Tuberculosis medications such as rifampin (Rimactane, Rifadin, in Rifater, in Rifamate)
Potassium supplements or salt substitutes
Corticosteroids such as dexamethasone (Dexpak, Decadron, Dexasone, others), budesonide (Entocort), betamethasone (Celestone), cortisone (Cortone), hydrocortisone (Cortef, Hydrocortone), fludrocortisone (Florinef), methylprednisolone (Medrol, Meprolone, others), prednisone (Meticorten, Deltasone, Sterapred, others), prednisolone (Prelone, others), and triamcinolone (Aristocort, Azmacort)
Corticotropin (H.P., ACTH, Acthar Gel)
Diabetes medications, including insulin and oral medications

The above list may not describe all the potential interactions of losartan hydrochlorothiazide. Give your doctor or pharmacist a complete list of your medications, including prescription drugs, nonprescription drugs, dietary supplements, and herbal remedies. Also, tell your healthcare professional if you smoke, drink alcohol, or use recreational drugs because some of these substances can cause serious health complications when used with prescription medications.

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