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Losartan + hydrochlorothiazide oral


Oral formulations of losartan with hydrochlorothiazide.

Drugs List

  • COZAAR-COMP 100mg+12.5mg tablets
  • COZAAR-COMP 100mg+25mg tablets
  • COZAAR-COMP 50mg+12.5mg tablets
  • losartan 100mg and hydrochlorothiazide 12.5mg tablets
  • losartan 100mg and hydrochlorothiazide 25mg tablets
  • losartan 50mg and hydrochlorothiazide 12.5mg tablets
  • Therapeutic Indications


    Hypertension-not adequately controlled by individual components


    Titration with the individual components (losartan and hydrochlorothiazide) is recommended. When clinically appropriate direct change from monotherapy to the fixed combination maybe considered in patients whose blood pressure is not adequately controlled.

    In general, the antihypertensive effect is attained within 3 to 4 weeks after initiation of therapy.


    Initial dose: 50 mg losartan potassium and 12.5 mg hydrochlorothiazide once daily. The dose may be increased to 100 mg losartan potassium and 25 mg hydrochlorothiazide once daily in patients who do not respond adequately to 50 mg losartan potassium and 12.5 mg hydrochlorothiazide once daily.

    The maximum dose is 100 mg losartan potassium and 25 mg hydrochlorothiazide once daily.


    Initial dose: 50 mg losartan potassium and 12.5 mg hydrochlorothiazide once daily. The dose may be increased to 100 mg losartan potassium and 25 mg hydrochlorothiazide once daily in patients who do not respond adequately to 50 mg losartan potassium and 12.5 mg hydrochlorothiazide once daily.

    The maximum dose is 100 mg losartan potassium and 25 mg hydrochlorothiazide once daily.

    Additional Dosage Information

    100 mg losartan potassium and 12.5 mg hydrochlorothiazide is available for patients titrated to 100 mg losartan potassium who require additional blood pressure control.


    Children under 18 years
    Addison's disease
    Biliary obstruction
    Refractory hypokalaemia
    Refractory hyponatraemia
    Renal artery stenosis
    Renal impairment - creatinine clearance below 30 ml/minute
    Severe hepatic impairment
    Symptomatic hyperuricaemia

    Precautions and Warnings

    Predisposition to narrow angle glaucoma
    Aortic stenosis
    Cerebral ischaemia
    Diabetes mellitus
    Electrolyte imbalance
    Glucose-galactose malabsorption syndrome
    History of angioedema
    History of hepatic impairment
    History of skin cancer
    Hypertrophic obstructive cardiomyopathy
    Kidney transplantation
    Lactose intolerance
    Mitral stenosis
    Peripheral vascular disease
    Renal impairment - creatinine clearance 30-50ml/minute
    Renovascular disorder
    Severe cardiac dysfunction
    Systemic lupus erythematosus

    Correct electrolyte disorders before treatment
    May decrease glucose tolerance in patients with diabetes mellitus
    May exacerbate or activate systemic lupus erythematosus
    Patients with primary aldosteronism may not benefit from this treatment
    Switch to more suitable alternative before planned pregnancy
    Advise ability to drive/operate machinery may be affected by side effects
    Afro-Caribbean or black patients may show reduced response
    Correct volume and/or salt depletion before initiating therapy
    Contains lactose
    Evaluate renal function before and during treatment
    Monitor serum electrolytes before and during treatment
    Monitor antidiabetic drug treatment
    Monitor blood / urinary glucose in patients suspected of latent diabetes
    Monitor serum potassium regularly
    Advise patient of increased risk of non-melanoma skin cancer
    Advise patient to monitor for and report any skin changes
    Excess consumption of liquorice may increase the risk of hypokalaemia
    Increased risk of hyperkalaemia with K+ suppl. and K+ sparing diuretic
    Increases in cholesterol and triglyceride levels may be seen
    May cause hyperuricaemia
    May precipitate gout
    Discontinue before parathyroid function tests
    Advise patient to seek advice at first indications of pregnancy
    Discontinue if acute respiratory distress syndrome is suspected
    Discontinue if patient develops decreased visual acuity +/or ocular pain
    Advise patient not to take NSAIDs unless advised by clinician
    Hypotensive effects may be potentiated by alcohol
    Advise on problems of salt substitutes/high intake of potassium-rich food
    Advise patient to avoid grapefruit products
    Female: Ensure adequate contraception during treatment
    Advise pt. to minimise exposure to sunlight & avoid sunlamps during therapy

    Thiazides may decrease urinary calcium excretion and may cause intermittent and slight elevation of serum calcium. Marked hypercalcaemia may be evidence of hidden hyperparathyroidism. Thiazides should be discontinued before carrying out tests for parathyroid function.

    In patients whose renal function may depend on the activity of the renin-angiotensin system (patients with severe congestive heart failure), treatment with ACE inhibitors has been associated with oliguria and/ or progressive azotaemia and in rare cases with acute renal failure and/ or death. As losartan with hydrochlorothiazide contains an angiotensin II antagonist, it cannot be excluded that the use of this medication may be associated with impairment of the renal function.

    An idiosyncratic reaction resulting in choroidal effusion with visual field defect, transient myopia and acute closed angle glaucoma may occur. Symptoms including acute onset of decreased visual acuity or ocular pain may occur within hours to weeks of initiation of this product and can lead to permanent vision loss. If symptoms occur treatment should be discontinued and prompt medical or surgical treatments should be considered if the intraocular pressure remains uncontrolled.

    Rare cases of acute respiratory toxicity including acute respiratory distress syndrome (ARDS) have been reported following treatment with hydrochlorothiazide. Symptoms can develop within minutes to hours of taking hydrochlorothiazide. If a diagnosis of ARDS is suspected, treatment should be withdrawn. This product should not be administered to a patient who has previously developed ARDS associated with hydrochlorothiazide.

    Pregnancy and Lactation


    Losartan with hydrochlorothiazide is contraindicated in pregnancy.

    Angiotensin II receptor antagonists may be associated with similar risks as ACE inhibitors. Angiotensin II receptor antagonist exposure during the second and third trimesters is known to induce human foetotoxicity (decreased renal function, oligohydramnios, skull ossification retardation) and neonatal toxicity (renal failure, hypotension, hyperkalaemia).

    The MHRA states that the use of angiotensin II receptor antagonists in late pregnancy has been associated with adverse effects on the foetal kidney and other congenital anomalies, therefore angiotensin II receptor antagonists should not be used at any stage during of pregnancy unless absolutely necessary and only then after the potential risks and benefits have been discussed with the patient.

    Exposure to angiotensin II receptor antagonists during the first trimester has been inconclusive, however, a small increase in risk cannot be excluded and a detailed ultrasound is recommended.

    If pregnancy is detected during therapy, losartan with hydrochlorothiazide should be discontinued as soon as possible and alternative treatment should be offered. Guidelines advise that women who are taking angiotensin II receptor blockers are told that there is an increased risk of congenital abnormalities if these drugs are taken during pregnancy and other antihypertensive treatments should be discussed and offered.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Losartan with hydrochlorothiazide is contraindicated in breastfeeding.

    Schaefer (2007) suggests that accidental administration of a single dose does not require weaning, however, therapy should be changed to an antihypertensive which has been better studied in breastfeeding. The MHRA concludes that the use of angiotensin II receptor antagonists in breastfeeding mothers is not recommended. Alternative agents with more established safety profiles during breastfeeding are preferable, especially while nursing a newborn or preterm baby.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Side Effects

    Acute respiratory distress syndrome
    Altered liver enzymes values
    Anaphylactic reaction
    Anaphylactoid-like reaction
    Blood glucose disturbances
    Blood lipid changes
    Choroidal effusion
    Decrease in haemoglobin and haematocrit
    Dry mouth
    Dry skin
    Electrolyte disturbances
    Eye irritation
    Gastro-intestinal disturbances
    Henoch-Schonlein purpura
    Impaired memory
    Increase in blood urea or creatinine
    Increased sweating
    Interstitial nephritis
    Intrahepatic cholestasis
    Joint swelling
    Liver function disturbances
    Micturition disorders
    Muscle spasm
    Myocardial infarction
    Narrow angle glaucoma
    Necrotising angiitis
    Ocular pain
    Orthostatic hypotension
    Panic attack
    Peripheral neuropathy
    Reduced libido
    Renal failure
    Second and third degree AV block
    Serum bilirubin increased
    Sinus disorder
    Sleep disturbances
    Toxic epidermal necrolysis
    Upper respiratory tract infection
    Urinary tract infections
    Visual disturbances


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: October 2016

    Reference Sources

    Summary of Product Characteristics: Cozaar-Comp 50/12.5 mg, 100/12.5 mg and 100/25 mg Film-coated Tablets. Merck Sharp & Dohme Ltd. Revised November 2022.

    Summary of Product Characteristics: Losartan potassium/Hydrochlorothiazide 50/12.5 mg Film-coated Tablets. Actavis UK Ltd. Revised October 2015.

    Summary of Product Characteristics: Losartan potassium/Hydrochlorothiazide 100/12.5 mg Film-coated Tablets. Actavis UK Ltd. Revised October 2015.

    Summary of Product Characteristics: Losartan potassium/Hydrochlorothiazide 100/25 mg Film-coated Tablets. Actavis UK Ltd. Revised October 2015.

    MHRA Drug Safety Update November 2018
    Available at:
    Last accessed: 08 January 2019

    NICE Evidence Services Available at: Last accessed: 06 September 2022.

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