Irbesartan and Hydrochlorothiazide

Clinical summary

Indications and usage Irbesartan and hydrochlorothiazide tablets are indicated for the treatment of hypertension. Irbesartan and hydrochlorothiazide tablets may be used in patients whose blood pressure is not adequately controlled on monotherapy. Irbesartan and hydrochlorothiazide tablets may also be used as initial therapy in patients who are likely to need multiple drugs to achieve their blood pressure goals. The choice of irbesartan and hydrochlorothiazide tablets as initial therapy for hypertension should be based on an assessment of potential benefits and risks. Patients with stage 2 (moderate or severe) hypertension are at relatively high risk for cardiovascular events (such as strokes, heart attacks, and heart failure), kidney failure, and vision problems, so prompt treatment is clinically relevant. The decision to use a combination as initial therapy should be individualized and may be shaped by considerations such as the baseline blood pressure, the target goal, and the incremental likelihood of achieving goal with a combination compared with monotherapy. Data from Studies V and VI [see Clinical Studies ( 14.2 )] provide estimates of the probability of reaching a blood pressure goal with irbesartan and hydrochlorothiazide tablets compared to irbesartan or hydrochlorothiazide (HCTZ) monotherapy. The relationship between baseline blood pressure and achievement of a SeSBP <140 or <130 mmHg or SeDBP <90 or <80 mmHg in patients treated with irbesartan and hydrochlorothiazide tablets compared to patients treated with irbesartan or HCTZ monotherapy are shown in Figures 1a through 2b. Figure 1a: Probability of Achieving SBP <140 mmHg in Patients from Initial Therapy Studies V (Week 8) and VI (Week 7) * Figure 1b: Probability of Achieving SBP <130 mmHg in Patients from Initial Therapy Studies V (Week 8) and VI (Week 7) * Figure 2a: Probability of Achieving DBP <90 mmHg in Patients from Initial Therapy Studies V (Week 8) and VI (Week 7) * Figure 2b: Probability of Achieving DBP <80 mmHg in Patients from Initial Therapy Studies V (Week 8) and VI (Week 7) * * For all probability curves, patients without blood pressure measurements at Week 7 (Study VI) and Week 8 (Study V) were counted as not reaching goal (intent-to-treat analysis). The above graphs provide a rough approximation of the likelihood of reaching a targeted blood pressure goal (e.g., Week 8 sitting systolic blood pressure ≤140 mmHg) for the treatment groups. The curve of each treatment group in each study was estimated by logistic regression modeling from all available data of that treatment group. The estimated likelihood at the right tail of each curve is less reliable due to small numbers of subjects with high baseline blood pressures. For example, a patient with a blood pressure of 180/105 mmHg has about a 25% likelihood of achieving a goal of <140 mmHg (systolic) and 50% likelihood of achieving <90 mmHg (diastolic) on irbesartan alone (and lower still likelihoods on HCTZ alone). The likelihood of achieving these goals on irbesartan and hydrochlorothiazide tablets rises to about 40% (systolic) or 70% (diastolic). Standard dosing General Considerations Maximum effects within 2 to 4 weeks after dose change. ( 2.1 ) Renal impairment: Not recommended for patients with severe renal impairment (creatinine clearance <30 mL/min). ( 2.1 , 5.8 ) Hypertension Initiate with 150/12.5 mg. Titrate to 300/12.5 mg then 300/25 mg if needed. ( 2.2 ) Replacement therapy: May be substituted for titrated components. ( 2.3 ) Contraindications Irbesartan 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 coadminister aliskiren with irbesartan and hydrochlorothiazide tablets in patients with diabetes [see Drug Interactions ( 7 )]. Key warnings Hypotension: Correct volume depletion prior to administration. ( 5.2 ) Impaired renal function. ( 5.7 ) Thiazide diuretics may cause an exacerbation or activation of systemic lupus erythematosus. ( 5.4 ) Acute angle-closure glaucoma, acute myopia, and choroidal effusion. ( 5.8 ) Drug interactions NSAIDs and selective COX-2 inhibitors: Can reduce diuretic, natriuretic of diuretic, may lead to increased risk of renal impairment and reduced antihypertensive effect. Monitor renal function periodically. ( 7 ) Dual blockade of the renin-angiotensin system: Increased risk of renal impairment, hypotension, and hyperkalemia. ( 7 ) Antidiabetic drugs: Dosage adjustment of antidiabetic may be required. ( 7 ) Cholestyramine and colestipol: Reduced absorption of thiazides. ( 7 ) Lithium: Increases in serum lithium concentrations and lithium toxicity. ( 7 ) Carbamazepine: Increased risk of hyponatremia. ( 7 ) Pregnancy guidance Risk Summary Irbesartan and hydrochlorothiazide