LOSARTAN POTASSIUM AND HYDROCHLOROTHIAZIDE

Losartan potassium and hydrochlorothiazide 50 mg/12.5 mg, losartan potassium and hydrochlorothiazide 100 mg/12.5 mg and losartan potassium and hydrochlorothiazide 100 mg/25 mg, combine an angiotensin II receptor (type AT 1 ) antagonist and a diuretic, hydrochlorothiazide. Losartan potassium, a non-peptide molecule, is chemically described as 2-butyl-4-chloro-1-[ p- ( o -1 H -tetrazol-5-ylphenyl)benzyl]imidazole-5-methanol monopotassium salt. Its molecular formula is C 22 H 22 ClKN 6 O, and its structural formula is: Losartan potassium USP is a white to off-white powder with a molecular weight of 461.01. It is freely soluble in water, soluble in alcohols, and slightly soluble in common organic solvents, such as acetonitrile and methyl ethyl ketone. Oxidation of the 5-hydroxymethyl group on the imidazole ring results in the active metabolite of losartan. Hydrochlorothiazide is 6-chloro-3,4-dihydro-2 H -1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide. Its molecular formula is C 7 H 8 ClN 3 O 4 S 2 and its structural formula is: Hydrochlorothiazide USP is a white or practically white, practically odorless, crystalline powder with a molecular weight of 297.74, which is slightly soluble in water, but freely soluble in sodium hydroxide solution. Losartan potassium and hydrochlorothiazide is available for oral administration in three tablet combinations of losartan and hydrochlorothiazide. Losartan potassium and hydrochlorothiazide tablets USP, 50 mg/12.5 mg contain 50 mg of losartan potassium USP and 12.5 mg of hydrochlorothiazide USP. Losartan potassium and hydrochlorothiazide tablets USP, 100 mg/12.5 mg contain 100 mg of losartan potassium USP and 12.5 mg of hydrochlorothiazide USP. Losartan potassium and hydrochlorothiazide tablets USP, 100 mg/25 mg contain 100 mg of losartan potassium USP and 25 mg of hydrochlorothiazide USP. Inactive ingredients are colloidal silicon dioxide, hydroxypropyl cellulose, hypromellose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, pregelatinised starch (maize), and titanium dioxide. Losartan potassium and hydrochlorothiazide 50 mg/12.5 mg and losartan potassium and hydrochlorothiazide 100 mg/25 mg also contain D&C yellow No. 10 aluminum lake. Losartan potassium and hydrochlorothiazide 50 mg/12.5 mg contains 4.24 mg (0.108 mEq) of potassium, losartan potassium and hydrochlorothiazide 100 mg/12.5 mg contains 8.48 mg (0.217 mEq) of potassium, and losartan potassium and hydrochlorothiazide 100 mg/25 mg contains 8.48 mg (0.217 mEq) of potassium. Losartan Potassium Chemical Structure Hydrochlorothiazide Chemical Structure

Hypertension Losartan potassium and hydrochlorothiazide tablets, USP are indicated for the treatment of hypertension. This fixed dose combination is not indicated for initial therapy of hypertension, except when the hypertension is severe enough that the value of achieving prompt blood pressure control exceeds the risk of initiating combination therapy in these patients (see CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects , and DOSAGE AND ADMINISTRATION ). Hypertensive Patients with Left Ventricular Hypertrophy Losartan potassium and hydrochlorothiazide tablets, USP are indicated to reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy, but there is evidence that this benefit does not apply to Black patients (see PRECAUTIONS, Race , CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects, Losartan Potassium, Reduction in the Risk of Stroke, Race , and DOSAGE AND ADMINISTRATION ).

Hypertension Dosing must be individualized. The usual starting dose of losartan is 50 mg once daily, with 25 mg recommended for patients with intravascular volume depletion (e.g., patients treated with diuretics) (see WARNINGS, Hypotension - Volume-Depleted Patients ) and patients with a history of hepatic impairment (see WARNINGS, Impaired Hepatic Function ). Losartan can be administered once or twice daily at total daily doses of 25 to 100 mg. If the antihypertensive effect measured at trough using once-a-day dosing is inadequate, a twice-a-day regimen at the same total daily dose or an increase in dose may give a more satisfactory response. Hydrochlorothiazide is effective in doses of 12.5 to 50 mg once daily and can be given at doses of 12.5 to 25 mg as losartan potassium and hydrochlorothiazide tablets. To minimize dose-independent side effects, it is usually appropriate to begin combination therapy only after a patient has failed to achieve the desired effect with monotherapy. The side effects (see WARNINGS ) of losartan are generally rare and apparently independent of dose; those of hydrochlorothiazide are a mixture of dose-dependent (primarily hypokalemia) and dose-independent phenomena (e.g., pancreatitis), the former much more common than the latter. Therapy with any combination of losartan and hydrochlorothiazide will be associated with both sets of dose-independent side effects. Replacement Therapy The combination may be substituted for the titrated components. Dose Titration by Clinical Effect A patient whose blood pressure is not adequately controlled with losartan monotherapy (see above) or hydrochlorothiazide alone may be switched to losartan potassium and hydrochlorothiazide tablets 50 mg/12.5 mg once daily. If blood pressure remains uncontrolled after about 3 weeks of therapy, the dose may be increased to two tablets of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily or one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily. A patient whose blood pressure is not adequately controlled with losartan 100 mg monotherapy (see above) may be switched to losartan potassium and hydrochlorothiazide tablets 100 mg/12.5 mg once daily. If blood pressure remains uncontrolled after about 3 weeks of therapy, the dose may be increased to two tablets of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily or one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily. A patient whose blood pressure is inadequately controlled by 25 mg once daily of hydrochlorothiazide, or is controlled but who experiences hypokalemia with this regimen, may be switched to losartan potassium and hydrochlorothiazide tablets 50 mg/12.5 mg once daily, reducing the dose of hydrochlorothiazide without reducing the overall expected antihypertensive response. The clinical response to losartan potassium and hydrochlorothiazide tablets 50 mg/12.5 mg should be subsequently evaluated, and if blood pressure remains uncontrolled after about 3 weeks of therapy, the dose may be increased to two tablets of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily or one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily. The usual dose of losartan potassium and hydrochlorothiazide is one tablet of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily. More than two tablets of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily or more than one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily is not recommended. The maximal antihypertensive effect is attained about 3 weeks after initiation of therapy. Use in Patients with Renal Impairment The usual regimens of therapy with losartan potassium and hydrochlorothiazide tablets may be followed as long as the patient's creatinine clearance is greater than 30 mL/min. In patients with more severe renal impairment, loop diuretics are preferred to thiazides, so losartan potassium and hydrochlorothiazide tablets are not recommended. Patients with Hepatic Impairment Losartan potassium and hydrochlorothiazide tablets are not recommended for titration in patients with hepatic impairment (see WARNINGS, Impaired Hepatic Function ) because the appropriate 25 mg starting dose of losartan cannot be given. Severe Hypertension The starting dose of losartan potassium and hydrochlorothiazide tablets for initial treatment of severe hypertension is one tablet of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily (see CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects ). For patients who do not respond adequately to losartan potassium and hydrochlorothiazide tablets 50 mg/12.5 mg after 2 to 4 weeks of therapy, the dosage may be increased to one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily. The maximum dose is one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily. Losartan potassium and hydrochlorothiazide tablets are not recommended as initial therapy in patients with hepatic impairment (see WARNINGS, Impaired Hepatic Function ) because the appropriate 25 mg starting dose of losartan cannot be given. It is also not recommended for use as initial therapy in patients with intravascular volume depletion (e.g., patients treated with diuretics, see WARNINGS, Hypotension - Volume-Depleted Patients ). Hypertensive Patients with Left Ventricular Hypertrophy Treatment should be initiated with losartan potassium 50 mg once daily. Hydrochlorothiazide 12.5 mg should be added or losartan potassium and hydrochlorothiazide tablets 50 mg/12.5 mg substituted if the blood pressure reduction is inadequate. If additional blood pressure reduction is needed, losartan potassium 100 mg and hydrochlorothiazide 12.5 mg or losartan potassium and hydrochlorothiazide tablets 100 mg/12.5 mg may be substituted, followed by losartan potassium 100 mg and hydrochlorothiazide 25 mg or losartan potassium and hydrochlorothiazide tablets 100 mg/25 mg. For further blood pressure reduction other antihypertensives should be added (see CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects, Losartan Potassium, Reduction in the Risk of Stroke ). Losartan potassium and hydrochlorothiazide tablets may be administered with other antihypertensive agents. Losartan potassium and hydrochlorothiazide tablets may be administered with or without food.

Losartan potassium and hydrochlorothiazide tablets are contraindicated in patients who are hypersensitive to any component of this product. Because of the hydrochlorothiazide component, this product is contraindicated in patients with anuria or hypersensitivity to other sulfonamide-derived drugs. Do not co-administer aliskiren with losartan potassium and hydrochlorothiazide tablets in patients with diabetes.

Losartan potassium and hydrochlorothiazide has been evaluated for safety in 858 patients treated for essential hypertension and 3889 patients treated for hypertension and left ventricular hypertrophy. In clinical trials with losartan potassium and hydrochlorothiazide, no adverse experiences peculiar to this combination have been observed. Adverse experiences have been limited to those that were reported previously with losartan potassium and/or hydrochlorothiazide. The overall incidence of adverse experiences reported with the combination was comparable to placebo. In general, treatment with losartan potassium and hydrochlorothiazide was well tolerated. For the most part, adverse experiences have been mild and transient in nature and have not required discontinuation of therapy. In controlled clinical trials, discontinuation of therapy due to clinical adverse experiences was required in only 2.8% and 2.3% of patients treated with the combination and placebo, respectively. In these double-blind controlled clinical trials, the following adverse experiences reported with losartan and hydrochlorothiazide occurred in ≥1 percent of patients, and more often on drug than placebo, regardless of drug relationship: Table 1: Losartan Potassium and Hydrochlorothiazide (n=858) Placebo (n=173) Body as a Whole Abdominal pain 1.2 0.6 Edema/swelling 1.3 1.2 Cardiovascular Palpitation 1.4 0 Musculoskeletal Back pain 2.1 0.6 Nervous/Psychiatric Dizziness 5.7 2.9 Respiratory Cough 2.6 2.3 Sinusitis 1.2 0.6 Upper respiratory infection 6.1 4.6 Skin Rash 1.4 0 The following adverse events were also reported at a rate of 1% or greater, but were as, or more, common in the placebo group in studies of essential hypertension: asthenia/fatigue, diarrhea, nausea, headache, bronchitis, pharyngitis. Adverse events occurred at about the same rates in men and women. Adverse events were somewhat more frequent in the elderly compared to non-elderly patients and somewhat more frequent in Blacks compared to non-Blacks for both the losartan and hydrochlorothiazide and the control groups. A patient with known hypersensitivity to aspirin and penicillin, when treated with losartan potassium, was withdrawn from study due to swelling of the lips and eyelids and facial rash, reported as angioedema, which returned to normal 5 days after therapy was discontinued. Superficial peeling of palms and hemolysis were reported in one subject treated with losartan potassium. Losartan Potassium Other adverse experiences that have been reported with losartan, without regard to causality, are listed below: Body as a Whole: chest pain, facial edema, fever, orthostatic effects, syncope Cardiovascular: angina pectoris, arrhythmias including atrial fibrillation, sinus bradycardia, tachycardia, ventricular tachycardia and ventricular fibrillation, CVA, hypotension, myocardial infarction, second degree AV block Digestive: anorexia, constipation, dental pain, dry mouth, dyspepsia, flatulence, gastritis, vomiting General disorders and administration site conditions: malaise Hematologic: anemia Metabolic: gout Musculoskeletal: arm pain, arthralgia, arthritis, fibromyalgia, hip pain, joint swelling, knee pain, leg pain, muscle cramps, muscle weakness, musculoskeletal pain, myalgia, shoulder pain, stiffness Nervous System/Psychiatric: anxiety, anxiety disorder, ataxia, confusion, depression, dream abnormality, hypesthesia, insomnia, libido decreased, memory impairment, migraine, nervousness, panic disorder, paresthesia, peripheral neuropathy, sleep disorder, somnolence, tremor, vertigo Respiratory: dyspnea, epistaxis, nasal congestion, pharyngeal discomfort, respiratory congestion, rhinitis, sinus disorder Skin: alopecia, dermatitis, dry skin, ecchymosis, erythema, flushing, photosensitivity, pruritus, sweating, urticaria Special Senses: blurred vision, burning/stinging in the eye, conjunctivitis, decrease in visual acuity, taste perversion, tinnitus Urogenital: impotence, nocturia, urinary frequency, urinary tract infection. Hydrochlorothiazide Other adverse experiences that have been reported with hydrochlorothiazide, without regard to causality, are listed below: Body as a Whole: weakness Digestive: pancreatitis, jaundice (intrahepatic cholestatic jaundice), sialadenitis, cramping, gastric irritation Hematologic: aplastic anemia, agranulocytosis, leukopenia, hemolytic anemia, thrombocytopenia Hypersensitivity: purpura, photosensitivity, urticaria, necrotizing angiitis (vasculitis and cutaneous vasculitis), fever, respiratory distress including pneumonitis and pulmonary edema Metabolic: hyperglycemia, glycosuria, hyperuricemia Musculoskeletal: muscle spasm Nervous System/Psychiatric: restlessness Renal: renal failure, renal dysfunction, interstitial nephritis Skin: erythema multiforme including Stevens-Johnson syndrome, exfoliative dermatitis including toxic epidermal necrolysis Special Senses: transient blurred vision, xanthopsia. Persistent dry cough (with an incidence of a few percent) has been associated with ACE-inhibitor use and in practice can be a cause of discontinuation of ACE-inhibitor therapy. Two prospective, parallel-group, double-blind, randomized, controlled trials were conducted to assess the effects of losartan on the incidence of cough in hypertensive patients who had experienced cough while receiving ACE-inhibitor therapy. Patients who had typical ACE-inhibitor cough when challenged with lisinopril, whose cough disappeared on placebo, were randomized to losartan 50 mg, lisinopril 20 mg, or either placebo (one study, n=97) or 25 mg hydrochlorothiazide (n=135). The double-blind treatment period lasted up to 8 weeks. The incidence of cough is shown below. Table 2: * Demographics = (89% Caucasian, 64% female) † Demographics = (90% Caucasian, 51% female) Study 1 * HCTZ Losartan Lisinopril Cough 25% 17% 69% Study 2 † Placebo Losartan Lisinopril Cough 35% 29% 62% These studies demonstrate that the incidence of cough associated with losartan therapy, in a population that all had cough associated with ACE-inhibitor therapy, is similar to that associated with hydrochlorothiazide or placebo therapy. Cases of cough, including positive re-challenges, have been reported with the use of losartan in postmarketing experience. Severe Hypertension In a clinical study in patients with severe hypertension (SiDBP ≥110 mmHg), the overall pattern of adverse events reported through six weeks of follow-up was similar in patients treated with losartan potassium and hydrochlorothiazide as initial therapy and in patients treated with losartan as initial therapy. There were no reported cases of syncope in either treatment group. There were 2 (0.6%) and 0 (0%) cases of hypotension reported in the group treated with losartan potassium and hydrochlorothiazide and the group treated with losartan, respectively. There were 3 (0.8%) and 2 (1.2%) cases of increased serum creatinine (>0.5 mg/dL) in the group treated with losartan potassium and hydrochlorothiazide and the group treated with losartan, respectively, during the same time period (see CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects, Severe Hypertension ). Postmarketing Experience The following additional adverse reactions have been reported in postmarketing experience: Digestive: Hepatitis has been reported rarely in patients treated with losartan. Hemic: Thrombocytopenia. Hypersensitivity: Angioedema, including swelling of the larynx and glottis, causing airway obstruction and/or swelling of the face, lips, pharynx, and/or tongue has been reported rarely in patients treated with losartan; some of these patients previously experienced angioedema with other drugs including ACE inhibitors. Vasculitis, including Henoch-Schönlein purpura, has been reported with losartan. Anaphylactic reactions have been reported. Metabolic and Nutrition: Hyperkalemia, hyponatremia have been reported with losartan. Musculoskeletal: Rare cases of rhabdomyolysis have been reported in patients receiving angiotensin II receptor blockers. Respiratory: Dry cough (see above) has been reported with losartan. Skin: Erythroderma has been reported with losartan. Laboratory Test Findings In controlled clinical trials, clinically important changes in standard laboratory parameters were rarely associated with administration of losartan potassium and hydrochlorothiazide. Creatinine, Blood Urea Nitrogen Minor increases in blood urea nitrogen (BUN) or serum creatinine were observed in 0.6 and 0.8 percent, respectively, of patients with essential hypertension treated with losartan potassium and hydrochlorothiazide alone. No patient discontinued taking losartan potassium and hydrochlorothiazide due to increased BUN. One patient discontinued taking losartan potassium and hydrochlorothiazide due to a minor increase in serum creatinine. Hemoglobin and Hematocrit Small decreases in hemoglobin and hematocrit (mean decreases of approximately 0.14 grams percent and 0.72 volume percent, respectively) occurred frequently in patients treated with losartan potassium and hydrochlorothiazide alone, but were rarely of clinical importance. No patients were discontinued due to anemia. Liver Function Tests Occasional elevations of liver enzymes and/or serum bilirubin have occurred. In patients with essential hypertension treated with losartan potassium and hydrochlorothiazide alone, no patients were discontinued due to these laboratory adverse experiences. Serum Electrolytes See PRECAUTIONS .

Losartan Potassium Losartan, administered for 12 days, did not affect the pharmacokinetics or pharmacodynamics of a single dose of warfarin. Losartan did not affect the pharmacokinetics of oral or intravenous digoxin. There is no pharmacokinetic interaction between losartan and hydrochlorothiazide. Coadministration of losartan and cimetidine led to an increase of about 18% in AUC of losartan but did not affect the pharmacokinetics of its active metabolite. Coadministration of losartan and phenobarbital led to a reduction of about 20% in the AUC of losartan and that of its active metabolite. A somewhat greater interaction (approximately 40% reduction in the AUC of active metabolite and approximately 30% reduction in the AUC of losartan) has been reported with rifampin. Fluconazole, an inhibitor of cytochrome P450 2C9, decreased the AUC of the active metabolite by approximately 40%, but increased the AUC of losartan by approximately 70% following multiple doses. Conversion of losartan to its active metabolite after intravenous administration is not affected by ketoconazole, an inhibitor of P450 3A4. The AUC of active metabolite following oral losartan was not affected by erythromycin, another inhibitor of P450 3A4, but the AUC of losartan was increased by 30%. Hydrochlorothiazide After oral administration of hydrochlorothiazide, diuresis begins within 2 hours, peaks in about 4 hours and lasts about 6 to 12 hours. Hydrochlorothiazide is not metabolized but is eliminated rapidly by the kidney. When plasma levels have been followed for at least 24 hours, the plasma half-life has been observed to vary between 5.6 and 14.8 hours. At least 61 percent of the oral dose is eliminated unchanged within 24 hours. Hydrochlorothiazide crosses the placental but not the blood-brain barrier and is excreted in breast milk. Drug Interactions Losartan Potassium No significant drug-drug pharmacokinetic interactions have been found in interaction studies with hydrochlorothiazide, digoxin, warfarin, cimetidine and phenobarbital. Rifampin, an inducer of drug metabolism, decreased the concentrations of losartan and its active metabolite (see CLINICAL PHARMACOLOGY, Drug Interactions ). In humans, two inhibitors of P450 3A4 have been studied. Ketoconazole did not affect the conversion of losartan to the active metabolite after intravenous administration of losartan, and erythromycin had no clinically significant effect after oral administration. Fluconazole, an inhibitor of P450 2C9, decreased active metabolite concentration and increased losartan concentration. The pharmacodynamic consequences of concomitant use of losartan and inhibitors of P450 2C9 have not been examined. Subjects who do not metabolize losartan to active metabolite have been shown to have a specific, rare defect in cytochrome P450 2C9. These data suggest that the conversion of losartan to its active metabolite is mediated primarily by P450 2C9 and not P450 3A4. As with other drugs that block angiotensin II or its effects, concomitant use of potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride), potassium supplements, or salt substitutes containing potassium may lead to increases in serum potassium (see PRECAUTIONS, Information for Patients, Potassium Supplements ). Lithium Increases in serum lithium concentrations and lithium toxicity have been reported during concomitant administration of lithium with angiotensin II receptor antagonists. Monitor serum lithium levels during concomitant use. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors) In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, co-administration of NSAIDs, including selective COX-2 inhibitors, with angiotensin II receptor antagonists (including losartan) may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving losartan and NSAID therapy. The antihypertensive effect of angiotensin II receptor antagonists, including losartan, may be attenuated by NSAIDs, including selective COX-2 inhibitors. Dual Blockade of the Renin-Angiotensin System (RAS) Dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy. The Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial enrolled 1448 patients with type 2 diabetes, elevated urinary-albumin-to-creatinine ratio, and decreased estimated glomerular filtration rate (GFR 30 to 89.9 mL/min), randomized them to lisinopril or placebo on a background of losartan therapy and followed them for a median of 2.2 years. Patients receiving the combination of losartan and lisinopril did not obtain any additional benefit compared to monotherapy for the combined endpoint of decline in GFR, end stage renal disease, or death, but experienced an increased incidence of hyperkalemia and acute kidney injury compared with the monotherapy group. Closely monitor blood pressure, renal function, and electrolytes in patients on losartan potassium and hydrochlorothiazide and other agents that affect the RAS. Do not co-administer aliskiren with losartan potassium and hydrochlorothiazide in patients with diabetes. Avoid use of aliskiren with losartan potassium and hydrochlorothiazide in patients with renal impairment (GFR <60 mL/min). Hydrochlorothiazide When administered concurrently, the following drugs may interact with thiazide diuretics: Alcohol, barbiturates, or narcotics - potentiation of orthostatic hypotension may occur. Antidiabetic drugs (oral agents and insulin) - dosage adjustment of the antidiabetic drug may be required. Other antihypertensive drugs - additive effect or potentiation. Cholestyramine and colestipol resins - Absorption of hydrochlorothiazide is impaired in the presence of anionic exchange resins. Single doses of either cholestyramine or colestipol resins bind the hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by up to 85 and 43 percent, respectively. Corticosteroids, ACTH, or glycyrrhizin (found in liquorice) - intensified electrolyte depletion, particularly hypokalemia. Pressor amines (e.g., norepinephrine) - possible decreased response to pressor amines but not sufficient to preclude their use. Skeletal muscle relaxants, nondepolarizing (e.g., tubocurarine) - possible increased responsiveness to the muscle relaxant. Lithium - should not generally be given with diuretics. Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity. Monitor serum lithium levels during concomitant use . Refer to the package insert for lithium preparations before use of such preparations with losartan potassium and hydrochlorothiazide. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors) - The administration of a non-steroidal anti-inflammatory agent, including a selective cyclooxygenase-2 inhibitor, can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics. Therefore, when losartan potassium and hydrochlorothiazide and non-steroidal anti-inflammatory agents, including selective cyclooxygenase-2 inhibitors, are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained. In patients receiving diuretic therapy, co-administration of NSAIDs with angiotensin receptor blockers, including losartan, may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving hydrochlorothiazide, losartan, and NSAID therapy.