Xarb 300

Xarb 300 contains 300 mg of the salt Irbesartan belonging to the Angiotensin II Receptor Blocker, which acts as an antihypertensive agent.

• Hypertension

Adult

Irbesartan is indicated for the treatment of hypertension, to lower blood pressure. Dose 150mg/day orally initially; may be increased to 300mg/day orally. Lowering blood pressure lowers the risk of fatal and non-fatal cardiovascular (CV) events, primarily strokes and myocardial infarction. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes including this drug. Irbesartan may be used alone or in combination with other antihypertensive agents.

Pediatric

In children, hypertension occurs less frequently, and the causes is more likely to be secondary to other causes, including renal parenchymal and renovascular disease. There is evidence to support the concept that essential hypertension may begin during childhood or adolescence. Thus, treatment of hypertension earlier in life may provide considerable cardiovascular and renal protection.

• Proteinuria reduction in chronic kidney diseases

Hypertension is a major contributor to the progression of chronic renal diseases 1,2 and is present in most patients with progressive renal disease and in all individuals with hypertensive nephrosclerosis. Irbesartan therapy was safely initiated and well tolerated by patients with renal disease.

• Nephropathy In Type 2 Diabetic Patients

Irbesartan is indicated for the treatment of diabetic nephropathy in patients with type 2 diabetes and hypertension, elevated serum creatinine, and proteinuria (>300mg/day). In this population, Irbesartan reduces the rate of progression of nephropathy as measured by the occurrence of doubling of serum creatinine or end-stage renal disease (need for dialysis or renal transplantation).

Xarb 300 contains 300 mg of the salt Irbesartan belonging to the Angiotensin II Receptor Blocker, which acts as an antihypertensive agent.

• Hypertension

Adult

The recommended initial dose of Irbesartan is 150mg once daily. Patients requiring further reduction in blood pressure should be titrated to 300mg once daily. A low dose of a diuretic may be added if blood pressure is not controlled by Irbesartan alone. Hydrochlorothiazide has been shown to have an additive effect. No dosage adjustment is necessary for elderly patients.

Pediatric

<6 years: Safety and efficacy have not been established.

6-12 years: Initial dose of 75mg as a single daily oral dose; maximum dose of 150mg once daily.

13-16 years: Initial dose of 150mg as a single daily oral dose; maximum dose of 300mg once daily.

• Proteinuria reduction in chronic kidney diseases

Once daily Irbesartan is given as monotherapy at a dose of 150-300mg or in combination with other antihypertensive drugs and is effective in reducing blood pressure in hypertensive patients with chronic renal disease.

• Nephropathy In Type 2 Diabetic Patients

The recommended dose is 300mg once daily.

• Volume and Salt-Depleted Patients

The recommended initial dose is 75mg once daily in patients with depletion of intravascular volume or salt (e.g., patients treated vigorously with diuretics or on hemodialysis)

• Fetal Toxicity

Xarb 300 can cause fetal harm when administered to a pregnant woman. The use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformities. Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death. When pregnancy is detected, discontinue Xarb 300 as soon as possible.

• Hypotension In Volume or Salt-Depleted Patients

In patients with an activated renin-angiotensin system, such as volume or salt-depleted patients (e.g., those being treated with high doses of diuretics), symptomatic hypotension may occur after initialization of treatment with Xarb 300. Correct volume or salt depletion prior to administration of Xarb 300 or use a lower starting dose.

• Impaired Renal Function

Changes in renal function including acute renal failure can be caused by drugs that inhibit the renin-angiotensin system. Patients whose renal function may depend in part on the activity of the renin-angiotensin system (e.g., patients with renal artery stenosis, chronic kidney disease, severe heart failure, or volume depletion) may be at particular risk of developing acute renal failure or death on Xarb 300. Monitor renal function periodically in these patients. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on Xarb 300.

The food warning while consuming Xarb 300 is that it should be taken in concentrations during its consumption:

• Potassium Rich Foods: Xarb 300 may cause high blood potassium levels. Hence, avoid potassium-rich food while taking this medicine.

The adverse reactions related to Xarb 300 contains 300 mg of the salt Irbesartan can be categorized as follows:

Common Adverse effects

• Diarrhea
• Fatigue
• Dizziness

Less Common Adverse effects

• Nausea
• Coughing
• Asthma
• Postural hypotension
• Muscle spasm

Rare adverse effect

• Skin rash
• Pruritus
• Angio edema

The clinically relevant drug interactions of the molecule Xarb 300 contains 300 mg of the salt Irbesartan are briefly summarized here.

• Agents Increasing Serum Potassium

Coadministration of Xarb 300 with another drug that raises serum potassium levels may result in hyperkalemia, sometimes severe. Monitor serum potassium in such patients.

• Lithium

Increases in serum lithium concentrations and lithium toxicity have been reported with the concomitant use of Xarb 300 and lithium. Monitor lithium levels in patients receiving Xarb 300 and lithium.

• Nonsteroidal 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, coadministration of NSAIDs, including selective COX-2 inhibitors, with angiotensin II receptor antagonists (including Xarb 300) may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving Xarb 300 and NSAID therapy.

The antihypertensive effect of angiotensin II receptor antagonists, including Xarb 300, 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, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy. Most patients receiving the combination of two RAS inhibitors do not obtain any additional benefit compared to monotherapy. In general, avoid the combined use of RAS inhibitors. Closely monitor blood pressure, renal function, and electrolytes in patients on Xarb 300 and other agents that affect the RAS.

The common side of Xarb 300 includes the following:

Major side effects

• Hyperkalemia
• Dizziness
• Tachycardia
• Dyspnea
• Orthostatic hypotension
• Swelling of face, lips, eyelids, tongue, hands, and feet

Minor side effects

• Rash
• Headache
• Diarrhoea
• Stomach pain
• Heartburn
• Dark coloured urine

• Pregnancy

Pregnancy Categories C (first trimester) and D (second and third trimesters)

The use of drugs that act directly on the renin-angiotensin system during the second and third trimesters of pregnancy has been associated with fetal and neonatal injury, including hypotension, neonatal skull hypoplasia, anuria, reversible or irreversible renal failure, and death. Oligohydramnios has also been reported, presumably resulting from decreased fetal renal function; oligohydramnios in this setting has been associated with fetal limb contractures, craniofacial deformation, and hypoplastic lung development. Prematurity, intrauterine growth retardation, and patent ductus arteriosus have also been reported, although it is not clear whether these occurrences were due to exposure to the drug. These adverse effects do not appear to have resulted from intrauterine drug exposure that has been limited to the first trimester. Mothers whose embryos and fetuses are exposed to an angiotensin II receptor antagonist only during the first trimester should be so informed. Nonetheless, when patients become pregnant, physicians should have the patient discontinue the use of Xarb 300 as soon as possible. Rarely (probably less often than once in every thousand pregnancies), no alternative to the drug acting on the renin-angiotensin system will be found. In these rare cases, the mothers should be apprised of the potential hazard to their fetuses, and a serial ultrasound examination should be performed to assess the intraamniotic environment. If oligohydramnios is observed, Xarb 300 should be discontinued unless it is considered lifesaving for the mother. Contraction stress testing (CST), a non-stress test (NST), or biophysical profiling (BPP) may be appropriate depending on the week of pregnancy. Patients and physicians should be aware, however, that oligohydramnios may not appear until after the fetus has sustained irreversible injury.

Infants with histories of in-utero exposure to an angiotensin II receptor antagonist should be closely observed for hypotension, oliguria, and hyperkalemia. If oliguria occurs, attention should be directed toward support of blood pressure and renal perfusion. Exchange transfusion or dialysis may be required as means of reversing hypotension and/or substituting for disordered renal function.

• Nursing Mothers

It is not known whether Xarb 300 is excreted in human milk, but Xarb 300 or some metabolite of Xarb 300 is secreted at low concentrations in the milk of lactating rats. Because of the potential for adverse effects on the infant, a decision should be made whether to discontinue nursing or discontinue the drug, considering the importance of the drug to the mother.

• Pediatric Use

Xarb 300, in a study at a dose of up to 4.5mg/kg/day, once daily, did not appear to lower blood pressure effectively in pediatric patients ages 6 to 16 years. Xarb 300 has not been studied in pediatric patients less than 6 years old.

• Geriatric Use

In elderly subjects (age 65-80 years), Xarb 300 elimination half-life was not significantly altered, but AUC and Cmax values were about 20% to 50% greater than those of young subjects (age 18-40 years). No dosage adjustment is necessary in the elderly.

• Renal Impairment

The pharmacokinetics of Xarb 300 were not altered in patients with renal impairment or in patients on hemodialysis. Xarb 300 is not removed by hemodialysis. No dosage adjustment is necessary in patients with mild to severe renal impairment unless a patient with renal impairment is also volume depleted.

• Hepatic Impairment

The pharmacokinetics of Xarb 300 following repeated oral administration were not significantly affected in patients with mild to moderate cirrhosis of the liver. No dosage adjustment is necessary in patients with hepatic insufficiency.

Pharmacodynamics

In healthy subjects, single oral Irbesartan doses of up to 300mg produced dose-dependent inhibition of the pressor effect of angiotensin II infusions. Inhibition was complete (100%) 4 hours following oral doses of 150mg or 300mg and partial inhibition was sustained for 24 hours (60% and 40% at 300mg and 150mg, respectively). In hypertensive patients, angiotensin II receptor inhibition following chronic administration of Irbesartan causes a 1.5- to 2-fold rise in angiotensin II plasma concentration and a 2- to 3-fold increase in plasma renin levels. Aldosterone plasma concentrations generally decline following Irbesartan administration, but serum potassium levels are not significantly affected at recommended doses. In hypertensive patients, chronic oral doses of Irbesartan (up to 300mg) had no effect on glomerular filtration rate, renal plasma flow, or filtration fraction. In multiple-dose studies in hypertensive patients, there were no clinically important effects on fasting triglycerides, total cholesterol, HDL-cholesterol, or fasting glucose concentrations. There was no effect on serum uric acid during chronic oral administration and no uricosuric effect.

Pharmacokinetics

• Absorption

Irbesartan is an orally active agent that does not require biotransformation into an active form. The oral absorption of Irbesartan is rapid and complete with an average absolute bioavailability of 60% to 80%. Following oral administration of Irbesartan, peak plasma concentrations of Irbesartan are attained at 1.5 to 2 hours after dosing. Food does not affect the bioavailability of Irbesartan. Irbesartan exhibits linear pharmacokinetics over the therapeutic dose range. The terminal elimination half-life of Irbesartan averaged 11 to 15 hours. Steady-state concentrations are achieved within 3 days. A limited accumulation of Irbesartan (<20%) is observed in plasma upon repeated once-daily dosing.

• Distribution

Irbesartan is 90% bound to serum proteins (primarily albumin and α1-acid glycoprotein) with negligible binding to cellular components of blood. The average volume of distribution is 53 liters to 93 liters. Total plasma and renal clearances are in the range of 157 mL/min to 176 mL/min and 3.0 mL/min to 3.5 mL/min, respectively. With repetitive dosing, Irbesartan accumulates to no clinically relevant extent.

• Metabolism and Elimination

Irbesartan is metabolized via glucuronide conjugation and oxidation. Following oral or intravenous administration of 14C-labeled Irbesartan, more than 80% of the circulating plasma radioactivity is attributable to unchanged Irbesartan. The primary circulating metabolite is the inactive Irbesartan glucuronide conjugate (approximately 6%). The remaining oxidative metabolites do not add appreciably to Irbesartan’s pharmacologic activity. Irbesartan and its metabolites are excreted by both biliary and renal routes.