LOSAZIDE® — Losartan Potassium + Hydrochlorothiazide — 50/12.5 mg & 100/25 mg
1. Disclaimer
This monograph is intended for educational and professional medical-reference purposes and is not a substitute for the current locally approved prescribing information, clinical judgment, or individualized medical advice. Treatment decisions, dose adjustments, laboratory monitoring, and management of adverse reactions should be made by qualified healthcare professionals according to the patient's clinical condition and applicable local guidance.
We do not guarantee the accuracy, currency or completeness of information regarding medications or medical products, and official sources should be verified before making any decisions. Readers are responsible for independently verifying the information before relying on it.
Because formulations, pack sizes, regulatory status, warnings, and approved indications may change, the current Egyptian-approved product information and outer packaging should be checked when regulatory or prescribing precision is required.
2. Summary
Losazide® is a fixed-dose antihypertensive combination containing losartan potassium, an angiotensin II AT₁-receptor antagonist, and hydrochlorothiazide (HCTZ), a thiazide diuretic.
The two components reduce blood pressure through complementary mechanisms: losartan inhibits the cardiovascular and renal effects of angiotensin II, while hydrochlorothiazide increases renal sodium and chloride excretion and reduces extracellular fluid volume. The combination generally produces greater antihypertensive activity than either component alone.
Current EIPICO product materials list Losazide in 50 mg/12.5 mg and 100 mg/25 mg film-coated tablet strengths.
3. Brand Name
Losazide®
4. Category
- Antihypertensive agent.
- Fixed-dose combination of:
- Angiotensin II receptor blocker (ARB) — losartan.
- Thiazide diuretic — hydrochlorothiazide.
- Pharmacotherapeutic group: Angiotensin II antagonists and diuretics.
- ATC code: C09DA01.
5. Active Ingredient
Losartan potassium + Hydrochlorothiazide.
Losartan is pharmacologically active itself and is also converted to an active carboxylic-acid metabolite, E-3174, which has substantially greater AT₁-receptor antagonistic activity on a weight-for-weight basis.
6. Pharmaceutical Form & Strength
Film-coated tablets.
Confirmed Losazide strengths listed by EIPICO:
- Losazide 50/12.5 mg: Losartan potassium 50 mg + Hydrochlorothiazide 12.5 mg.
- Losazide 100/25 mg: Losartan potassium 100 mg + Hydrochlorothiazide 25 mg.
These strengths are also consistent with Egyptian Losazide prescribing information.
Pack sizes may vary with market availability and over time; the current marketed Egyptian pack should therefore be checked directly.
7. Manufacturer & Marketing Authorization Holder
Manufacturer / product company:
Egyptian International Pharmaceutical Industries Co. (EIPICO), 10th of Ramadan City, Egypt. Egyptian Losazide product information identifies EIPICO and its 10th of Ramadan City manufacturing address.
EIPICO's current product catalogue continues to list Losazide 50/12.5 mg and 100/25 mg among its cardiovascular products.
Marketing Authorization Holder in Egypt: the current MAH should be verified against the latest Egyptian Drug Authority registration or current outer packaging when the information is required for regulatory purposes; the available product materials identify EIPICO as the manufacturer/product company but do not provide a separately stated current MAH field.
8. Mechanism of Action
Losartan
Losartan is a selective angiotensin II AT₁-receptor antagonist. Angiotensin II normally produces vasoconstriction, stimulates aldosterone secretion and contributes to sodium retention and cardiovascular remodeling.
Losartan and its active metabolite E-3174 inhibit physiologically relevant AT₁-mediated effects of angiotensin II. Losartan does not inhibit angiotensin-converting enzyme (ACE/kininase II) and therefore does not directly inhibit bradykinin degradation.
Hydrochlorothiazide
Hydrochlorothiazide is a thiazide diuretic that reduces renal tubular sodium and chloride reabsorption, thereby increasing their urinary excretion. The resulting diuresis decreases plasma volume and contributes to blood-pressure reduction. It may increase renin activity and aldosterone secretion and promote potassium loss.
Combined effect
The two agents exert additive antihypertensive effects. Losartan-mediated suppression of angiotensin II/aldosterone activity can also partially attenuate the potassium loss associated with hydrochlorothiazide. Losartan has a mild uricosuric effect and can partly offset thiazide-associated increases in serum uric acid.
9. Spectrum of Activity
Not applicable in the antimicrobial sense.
Losazide is not an anti-infective and therefore has no antibacterial, antiviral, antifungal or antiparasitic spectrum.
Its pharmacological activity consists of systemic AT₁-receptor blockade plus thiazide diuresis, producing sustained antihypertensive activity that can persist over a 24-hour dosing interval.
10. Pharmacokinetics
Losartan
After oral administration, losartan is well absorbed and undergoes first-pass metabolism. Its systemic bioavailability is approximately 33%.
Peak plasma concentrations are generally reached at about:
- Losartan: 1 hour.
- Active metabolite: 3–4 hours.
Food does not have a clinically important effect on the plasma concentration profile.
Losartan and its active metabolite are ≥99% protein bound, mainly to albumin. The apparent volume of distribution of losartan is approximately 34 L.
Approximately 14% of an administered dose is converted to the active metabolite. Losartan's terminal half-life is approximately 2 hours, while that of its active metabolite is approximately 6–9 hours.
About 4% of an oral dose is excreted unchanged in urine and approximately 6% as active metabolite. Following radiolabelled losartan, approximately 35% of radioactivity is recovered in urine and 58% in faeces.
Neither losartan nor its active metabolite is effectively removed by haemodialysis.
Hydrochlorothiazide
Hydrochlorothiazide is not substantially metabolized and is eliminated predominantly by the kidneys. Its reported plasma half-life is approximately 5.6–14.8 hours, and at least 61% of the oral dose may be eliminated unchanged within 24 hours.
Diuresis usually begins within approximately 2 hours, peaks around 4 hours and lasts approximately 6–12 hours, while antihypertensive activity may persist for up to 24 hours.
In mild-to-moderate alcoholic cirrhosis, exposure to losartan and its active metabolite may be markedly increased.
11. Indications
Losazide is indicated for the treatment of essential hypertension in patients whose blood pressure is not adequately controlled with losartan or hydrochlorothiazide alone. This indication is stated in Egyptian Losazide prescribing information and remains consistent with current losartan/HCTZ SmPCs.
It is generally not intended as initial antihypertensive therapy when dose titration with the individual components is appropriate.
12. Administration
Adults with hypertension
The usual maintenance regimen is:
Losazide 50/12.5 mg: one tablet once daily.
If blood pressure remains inadequately controlled and escalation is clinically appropriate:
Losazide 100/25 mg: one tablet once daily.
The usual maximum dose for these marketed strengths is losartan 100 mg/HCTZ 25 mg once daily.
The full antihypertensive effect may require approximately 3–4 weeks after initiation or dose adjustment.
Egyptian Losazide prescribing information contains the same 50/12.5-to-100/25 mg titration scheme.
Method of administration
- Administer orally once daily.
- May be taken with or without food.
- Swallow the tablet with water; current SmPC information specifies swallowing the tablet whole.
- It may be used with other antihypertensive agents when clinically appropriate.
- Correct clinically significant volume or sodium depletion before treatment.
13. Method of Preparation
No preparation or reconstitution is required.
Losazide is supplied as a ready-to-administer film-coated tablet. It should be administered orally with water according to the prescribed dose.
14. Contraindications
According to Egyptian Losazide prescribing information and contemporary international losartan/hydrochlorothiazide SmPCs, relevant contraindications include:
- Hypersensitivity to losartan, hydrochlorothiazide, sulfonamide-derived substances or product excipients.
- Therapy-resistant hypokalaemia.
- Hypercalcaemia that cannot be adequately corrected.
- Refractory hyponatraemia.
- Symptomatic hyperuricaemia or gout.
- Severe hepatic impairment, cholestasis or biliary obstructive disorders.
- Severe renal impairment, conventionally defined in the applicable SmPC as creatinine clearance <30 mL/min.
- Anuria.
- Second and third trimesters of pregnancy.
- Lactation, according to the Egyptian Losazide prescribing information available for this product.
- Concomitant aliskiren-containing therapy in patients with diabetes mellitus or renal impairment with GFR <60 mL/min/1.73 m².
The Egyptian Losazide prescribing information lists lactation as a contraindication. Contemporary international losartan/hydrochlorothiazide SmPCs generally state instead that the combination is not recommended during breastfeeding and that alternative antihypertensive treatments with better-established safety profiles are preferable, particularly when nursing a newborn or premature infant. The current Egyptian-approved prescribing information should therefore be followed for product-specific prescribing decisions.
15. Warnings & Precautions
Pregnancy and fetal toxicity
Drugs acting on the renin-angiotensin system can cause serious fetal harm. Losartan should not be initiated during pregnancy. Treatment should be discontinued promptly if pregnancy occurs and an appropriate alternative considered.
Exposure during the second and third trimesters may cause fetal renal dysfunction, oligohydramnios, impaired skull ossification, neonatal renal failure, hypotension, hyperkalaemia and death.
Hypotension and volume depletion
Symptomatic hypotension can occur, particularly in patients depleted of sodium or intravascular volume because of intensive diuretic therapy, vomiting, diarrhoea or dietary salt restriction. Correct depletion before starting treatment.
Renal function
Monitor renal function, particularly in patients with heart failure, chronic kidney disease, renal artery stenosis or other conditions in which renal perfusion depends on the renin-angiotensin system.
Acute deterioration in renal function can occur. Losartan requires particular caution in bilateral renal artery stenosis or stenosis of the artery to a solitary functioning kidney.
Electrolytes
Monitor potassium, sodium and renal function as clinically appropriate. Either component can alter electrolyte balance: losartan may increase potassium, while hydrochlorothiazide may cause hypokalaemia, hyponatraemia, hypomagnesaemia or metabolic alkalosis.
Angioedema
Facial, lip, tongue or laryngeal angioedema has been reported.
Intestinal angioedema has also been reported with angiotensin II receptor antagonists and may present with abdominal pain, nausea, vomiting or diarrhoea. Discontinue losartan if intestinal angioedema is diagnosed.
Dual RAAS blockade
Routine combination of an ARB with an ACE inhibitor or aliskiren is not recommended because it increases the risk of hypotension, hyperkalaemia and renal impairment. ACE inhibitor/ARB dual therapy should not be used in diabetic nephropathy.
Metabolic effects
Hydrochlorothiazide can:
- Impair glucose tolerance.
- Increase uric acid and precipitate gout.
- Produce mild hypercalcaemia.
- Affect serum lipids.
- Unmask previously latent diabetes.
Losartan's uricosuric effect partially attenuates, but does not eliminate, HCTZ-induced hyperuricaemia.
Acute ocular reactions
Hydrochlorothiazide, as a sulfonamide derivative, can rarely cause choroidal effusion, acute transient myopia and secondary angle-closure glaucoma. Sudden reduction in vision or eye pain requires urgent assessment and discontinuation of the offending drug when indicated. Untreated angle-closure glaucoma can result in permanent visual loss.
Non-melanoma skin cancer
Long-term cumulative exposure to hydrochlorothiazide has been associated in epidemiological studies with increased risk of non-melanoma skin cancer, particularly basal-cell and squamous-cell carcinoma. Patients should limit unnecessary UV exposure, use appropriate sun protection and report suspicious new or changing skin lesions.
Acute respiratory toxicity
Very rare severe acute respiratory toxicity, including acute respiratory distress syndrome (ARDS), has been reported after hydrochlorothiazide. Symptoms may develop within minutes to hours and can include dyspnoea, fever, pulmonary deterioration and hypotension. Hydrochlorothiazide should not be re-administered to a patient who previously experienced HCTZ-associated ARDS.
Additional precautions
Use caution in:
- Mild-to-moderate hepatic impairment.
- Heart failure.
- Aortic or mitral stenosis.
- Obstructive hypertrophic cardiomyopathy.
- Ischaemic cardiovascular or cerebrovascular disease.
- Systemic lupus erythematosus.
- Recent renal transplantation, for which clinical experience is limited.
The combination is generally not recommended for primary aldosteronism because such patients often respond poorly to drugs acting primarily through renin-angiotensin inhibition.
16. Drug Interactions
Important interactions include:
Potassium-raising therapy: potassium supplements, potassium-containing salt substitutes, potassium-sparing diuretics and other potassium-raising medicines, including trimethoprim-containing products, can increase the risk of hyperkalaemia.
ACE inhibitors/other ARBs/aliskiren: dual RAAS blockade increases the risk of hypotension, hyperkalaemia and renal impairment.
Lithium: both ARB- and diuretic-related mechanisms may reduce lithium clearance and increase lithium toxicity. Concomitant use is generally discouraged; if unavoidable, lithium levels require close monitoring.
NSAIDs, including COX-2 inhibitors: may reduce the antihypertensive and diuretic effects and increase the risk of renal deterioration, acute kidney injury and hyperkalaemia, particularly in elderly, dehydrated or renally impaired patients.
Rifampicin and fluconazole: may reduce concentrations of losartan's active metabolite.
Other antihypertensives, tricyclic antidepressants, antipsychotics, baclofen and amifostine: may increase hypotensive effects.
Antidiabetic therapy: thiazides can alter glucose tolerance; adjustment of insulin or oral antidiabetic therapy may be necessary.
Cholestyramine and colestipol: reduce HCTZ absorption. Current U.S. prescribing information recommends separating hydrochlorothiazide from these resins, administering HCTZ at least 4 hours before or 4–6 hours after the resin.
Corticosteroids, ACTH, stimulant laxatives, amphotericin B and glycyrrhizin: may increase the risk of potassium depletion.
Digitalis glycosides and QT-prolonging/antiarrhythmic drugs: thiazide-induced hypokalaemia or hypomagnesaemia can increase the risk of arrhythmia.
Allopurinol, probenecid and other antigout treatments: HCTZ may increase uric acid and may alter therapeutic requirements; thiazides may increase allopurinol hypersensitivity risk.
Cyclosporine: may increase hyperuricaemia and gout risk.
Calcium salts: serum calcium may rise because thiazides reduce urinary calcium excretion.
Carbamazepine: may increase the risk of symptomatic hyponatraemia.
Iodinated contrast media: diuretic-associated dehydration can increase acute kidney injury risk; appropriate hydration and clinical assessment are required.
Grapefruit juice: a current SmPC advises avoiding grapefruit juice because inhibition of relevant CYP enzymes may reduce formation of losartan's active metabolite and potentially reduce therapeutic effect.
17. Side Effects
In controlled hypertension studies of the fixed losartan/HCTZ combination, dizziness was the principal treatment-related adverse reaction occurring more frequently than placebo at an incidence of at least 1%.
Reported effects associated with the combination or its individual components include:
Cardiovascular and nervous system
Dizziness, headache, orthostatic hypotension, hypotension, syncope, palpitations and, less commonly, cardiac rhythm disturbances.
Gastrointestinal
Abdominal pain, nausea, diarrhoea, dyspepsia, vomiting, constipation and dry mouth.
Musculoskeletal
Muscle cramps, myalgia, back or limb pain; rhabdomyolysis has been reported with unknown frequency for losartan.
Renal and electrolyte effects
Renal impairment or renal failure, elevations of urea/creatinine, hyperkalaemia, hypokalaemia, hyponatraemia, hyperuricaemia and disturbances of glucose metabolism.
Hypersensitivity
Urticaria, rash, anaphylactic reactions and angioedema, including potentially serious airway involvement. Intestinal angioedema has also been reported.
Hepatic
Abnormal liver function tests and rare hepatitis; pancreatitis has also been reported.
Haematologic
Anaemia, thrombocytopenia, leukopenia, agranulocytosis, haemolytic anaemia and aplastic anaemia have been reported, particularly in association with hydrochlorothiazide.
Ocular
Blurred vision, choroidal effusion, acute myopia and acute angle-closure glaucoma.
Respiratory
Pneumonitis, pulmonary oedema and very rare ARDS have been reported with hydrochlorothiazide.
Dermatologic
Photosensitivity, rash, urticaria and rare severe cutaneous reactions. Long-term cumulative hydrochlorothiazide exposure is associated with an increased risk of non-melanoma skin cancer.
Patients should seek urgent medical attention for angioedema, severe breathing difficulty, sudden visual loss or eye pain, severe hypotension, markedly reduced urine output or other potentially serious reactions.
18. Use in Special Populations
Pregnancy
Losartan-containing therapy should be avoided during pregnancy.
Use during the first trimester is not recommended, and use during the second and third trimesters is contraindicated because of established fetotoxicity from renin-angiotensin system inhibition.
When pregnancy is detected, treatment should be stopped as soon as possible and an appropriate alternative antihypertensive considered.
Breastfeeding
Egyptian Losazide prescribing information lists lactation as a contraindication.
Contemporary international losartan/hydrochlorothiazide SmPCs generally state that the combination is not recommended during breastfeeding, because adequate safety information for losartan is lacking and hydrochlorothiazide passes into human milk. Higher thiazide doses may suppress milk production.
An antihypertensive with a better-established breastfeeding safety profile is generally preferred, especially for a newborn or premature infant. For product-specific prescribing in Egypt, the current Egyptian-approved prescribing information should be followed.
Renal impairment
No initial adjustment is usually required in moderate renal impairment (CrCl approximately 30–50 mL/min), but renal function and electrolytes require monitoring.
The fixed combination should not be used in severe renal impairment (CrCl <30 mL/min) under the referenced SmPC and Egyptian Losazide prescribing information and is not recommended in haemodialysis patients.
Hepatic impairment
Use cautiously in mild-to-moderate hepatic impairment because losartan exposure may increase substantially. The combination is contraindicated in severe hepatic impairment.
Elderly
Routine dose adjustment solely on the basis of age is generally not required, although renal function, electrolyte status and susceptibility to hypotension should be considered.
Children and adolescents
Adequate experience with this fixed combination in patients under 18 years is lacking in the referenced product information; use is therefore not recommended.
19. Storage Conditions
Product-specific Losazide prescribing information states:
Store at a temperature not exceeding 30°C and protect from light.
Keep the medicine in its original packaging where appropriate and out of the reach of children. If the currently marketed pack carries different storage instructions, the current pack instructions should take precedence.
20. Additional Sections
Monitoring
Depending on the patient's clinical condition, monitoring may include:
- Blood pressure.
- Serum creatinine/eGFR.
- Serum potassium and sodium.
- Other electrolytes when clinically indicated, including magnesium and calcium.
- Uric acid in patients with gout or hyperuricaemia.
- Blood glucose in patients with diabetes or impaired glucose tolerance.
- Clinical assessment for dehydration or orthostatic hypotension.
- Patients receiving hydrochlorothiazide should regularly check their skin for new or changing lesions and seek clinical evaluation of suspicious lesions. Appropriate periodic skin assessment may be considered, particularly in patients with substantial cumulative HCTZ exposure or a previous history of skin cancer.
Overdose
There is no specific antidote for the losartan/HCTZ combination.
Likely manifestations include hypotension and tachycardia from losartan, with bradycardia possible; HCTZ overdose primarily produces excessive diuresis, dehydration and electrolyte abnormalities such as hypokalaemia, hyponatraemia and hypochloraemia.
Management is supportive and directed at blood pressure, fluid status and electrolyte disturbances. Losartan and its active metabolite are not removed effectively by haemodialysis; the extent to which HCTZ is removed by haemodialysis has not been established.
Driving and operating machinery
Dizziness or drowsiness may occur, especially after treatment initiation or dose escalation. Patients should determine how the medicine affects them before driving or operating hazardous machinery.
Product excipients
Egyptian Losazide product information lists microcrystalline cellulose, pregelatinized starch, magnesium stearate, sodium starch glycolate, hydroxypropyl cellulose and colloidal silicon dioxide among the excipients.
Excipients should always be verified against the current pack if allergy or intolerance is clinically relevant because formulations can be revised.
21. Frequently Asked Questions (FAQ)
Q1. What is Losazide used for?
It is used to treat essential hypertension when blood pressure is not adequately controlled by losartan or hydrochlorothiazide alone.
Q2. Can Losazide be taken with food?
Yes. Losartan/HCTZ may be taken with or without food.
Q3. When does the full blood-pressure-lowering effect appear?
A substantial effect may occur earlier, but the full response after starting or changing the dose may require approximately 3–4 weeks.
Q4. Can potassium supplements or potassium salt substitutes be used with Losazide?
Not without medical advice. Losartan can increase serum potassium, and concomitant potassium-raising agents can cause clinically important hyperkalaemia.
Q5. Can Losazide be used during pregnancy?
Losartan-containing therapy should be avoided during pregnancy. It is contraindicated during the second and third trimesters and should be stopped promptly if pregnancy occurs.
Q6. Is Losazide suitable during breastfeeding?
Egyptian Losazide prescribing information lists lactation as a contraindication. Contemporary international losartan/HCTZ information generally states that the combination is not recommended during breastfeeding and that an alternative antihypertensive with a better-established safety profile is preferred, particularly while nursing a newborn or premature infant. Current locally approved prescribing information should be followed.
Q7. Why are blood tests sometimes required?
Losazide can affect renal function and levels of potassium, sodium, uric acid, glucose and other biochemical parameters. Monitoring helps detect clinically significant changes early.
Q8. Why is sun protection relevant?
Hydrochlorothiazide can cause photosensitivity, and high cumulative exposure has been associated with an increased risk of non-melanoma skin cancer. Appropriate sun protection and assessment of suspicious skin lesions are recommended.
Q9. What symptoms require urgent medical assessment?
Facial/tongue swelling or breathing difficulty, sudden eye pain or loss of vision, severe shortness of breath, profound dizziness or fainting, markedly reduced urine output, or severe skin reactions require prompt medical assessment.
Q10. Should treatment be stopped when blood pressure becomes normal?
No change or discontinuation should be made solely because a blood-pressure reading becomes normal. Controlled blood pressure may reflect effective treatment; therapy should be changed only under appropriate medical supervision.
22. References
- EIPICO — current product catalogue: lists Losazide® 50/12.5 mg and Losazide® 100/25 mg film-coated tablets and their active ingredients.
- Egyptian Losazide prescribing information: composition, approved indication, dosing, contraindications, renal/hepatic information, pregnancy and lactation information, storage, excipients and manufacturer details.
- UK electronic Medicines Compendium (emc), Losartan Potassium/Hydrochlorothiazide SmPC, current record updated in 2026: indications, dosing, contraindications, warnings, interactions, adverse effects and pharmacokinetics.
- Current losartan/HCTZ SmPC safety information: pregnancy, breastfeeding, intestinal angioedema, ARDS, non-melanoma skin cancer and acute ocular reactions.
- DailyMed — HYZAAR® (losartan potassium/hydrochlorothiazide), U.S. prescribing information, updated November 2025: fetal toxicity, drug interactions, ocular warnings and non-melanoma skin-cancer information.