Irbesartan is an angiotensin receptor blocker (ARB) used mainly for the treatment of hypertension. It competes with angiotensin II for binding at the AT1 receptor subtype. Unlike ACE inhibitors, ARBs do not have the adverse effect of dry cough. The use of ARBs is pending revision due to findings from several clinical trials suggesting that this class of drugs may be associated with a small increased risk of cancer.
Mechanism of Action of Irbesartan
Irbesartan is a nonpeptide tetrazole derivative and an angiotensin II antagonist that selectively blocks the binding of angiotensin II to the AT1 receptor. In the renin-angiotensin system, angiotensin I is converted by angiotensin-converting enzyme (ACE) to form angiotensin II. Angiotensin II stimulates the adrenal cortex to synthesize and secrete aldosterone, which decreases the excretion of sodium and increases the excretion of potassium. Angiotensin II also acts as a vasoconstrictor in vascular smooth muscle. Irbesartan, by blocking the binding of angiotensin II to the AT1 receptor, promotes vasodilation and decreases the effects of aldosterone. The negative feedback regulation of angiotensin II on renin secretion is also inhibited, but the resulting rise in plasma renin concentrations and consequent rise in angiotensin II plasma concentrations do not counteract the blood pressure–lowering effect that occurs. The action of ARBs is different from ACE inhibitors, which block the conversion of angiotensin I to angiotensin II, meaning that the production of angiotensin II is not completely inhibited, as the hormone can be formed via other enzymes. Also, unlike ACE inhibitors, irbesartan and other ARBs do not interfere with response to bradykinins and substance P, which allows for the absence of adverse effects that are present in ACE inhibitors (eg. dry cough).
Indications of Irbesartan
- High Blood Pressure
- Diabetic Kidney Disease
- Hypertension and microalbuminuria (>30 mg/24 h) or proteinuria (>900 mg/24 h).
- High Blood Pressure (Hypertension)
- Marfan Syndrome
- Alport Syndrome
- Treatment of uncomplicated hypertension,
- Isolated systolic hypertension and left ventricular hypertrophy.
- Delay or progression of diabetic nephropathy.
- Second line agent in the treatment of congestive heart failure,
- Systolic dysfunction,
- Risk of stroke in patients with hypertension and left ventricular hypertrophy.
- Diabetic nephropathy with an elevated serum creatinine and proteinuria
- For the treatment of hypertension, as well as diabetic nephropathy with an elevated serum creatinine and proteinuria (>300 mg/day) in patients with type 2 diabetes and hypertension.
- Irbesartan is also used as a second line agent in the treatment of congestive heart failure.
Therapeutic Indications of Irbesartan
- Irbesartan is indicated for the treatment of hypertension. It may be used alone or in combination with other antihypertensive agents.
- Irbesartan is indicated for the treatment of diabetic nephropathy with an elevated serum creatinine and proteinuria (>300 mg/day) in patients with type 2 diabetes and hypertension.
- 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).
- Angiotensin II receptor antagonists including irbesartan have been used in the management of congestive heart failure.
- Treatment of essential hypertension.
- Treatment of renal disease in patients with hypertension and type 2 diabetes mellitus as part of an antihypertensive medicinal product regimen (see section 5.1).
- Treatment of essential hypertension.
- Treatment of renal disease in patients with hypertension and type 2 diabetes mellitus as part of an antihypertensive medicinal product regimen.
- Irbesartan is an angiotensin II receptor antagonist indicated for the treatment of hypertension. It may be used either alone or in combination with other antihypertensive agents (ie, thiazide diuretics, beta-adrenergic blocking agents, and long-acting calcium-channel blocking agents).
- Irbesartan is also indicated for the treatment of renal disease in patients with hypertension and type 2 diabetes mellitus. Irbesartan is available in the following formulations: 75, 100, 150, or 300 mg unscored or film-coated tablets for oral administration.
- The usual recommended initial and maintenance dose is 150mg once daily, with or without food. However, initiation of therapy with 75 mg could be considered, particularly in haemodialysed patients and in the elderly over 75 years. In patients insufficiently controlled with 150 mg once daily, the dose of irbesartan can be increased to 300 mg, or other antihypertensive agents can be added.
- In hypertensive type 2 diabetic patients, therapy should be initiated at 150 mg of irbesartan once daily and titrated up to 300 mg once daily as the preferred maintenance dose for treatment of renal disease.
- Treatment of essential hypertension – Treatment of renal disease in patients with hypertension and type 2 diabetes mellitus as part of an antihypertensive medicinal product regimen
- Irbesartan is indicated in adults for the treatment of essential hypertension.
- It is also indicated for the treatment of renal disease in adult patients with hypertension and type 2 diabetes mellitus as part of an antihypertensive medicinal product regimen.
- Irbesartan is indicated in adults for the treatment of essential hypertension.It is also indicated for the treatment of renal disease in adult patients with hypertension and type 2 diabetes mellitus as part of an antihypertensive medicinal product regimen.
Contra Indications of Irbesartan
- Low amount of sodium in the blood
- High amount of potassium in the blood
- Decreased Neutrophils a Type of White Blood Cell
- Renal Artery Stenosis
- Abnormally low blood pressure
- Liver problems
- Severe renal impairment
- Decreased Blood Volume
Dosage of Irbesartan
Tablet : 75mg ,150mg ,300mg
150 mg/day PO initially; may be increased to 300 mg/day PO
Hypovolemia: 75 mg/day PO initially
Nephropathy in Type 2 Diabetes
75-300 mg/day PO
Side Effects of Irbesartan
The most common
- cold symptoms such as stuffy nose, sore throat, cough
- A dry cough
- Dizziness and light-headedness due to low blood pressure
- Fatigue, especially in the early stages
- Mouth dryness in the early stages
- The most common (a burning feeling in the chest, behind the breastbone or gullet)
- Abdominal or stomach pain
- Nausea, vomiting,
- painful or swollen gums
- numbness or heavy feeling in the jaw
- dull, aching pain in the hip, groin, or thigh
- stomach pain,
- a headache,
- reversible hair loss or thinning, and
- chills or fever
- a headache, severe and throbbing
- joint or back pain
- muscle aching or cramping
- muscle pains or stiffness
- chest pressure or squeezing pain in the chest
- excessive sweating
- sudden drowsiness or need to sleep
- coughing up blood
- liver problems–nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes)
- decreased amount of urine
- change in vision
- chest pain or tightness
- a cough
- arm, back, or jaw pain
- blurred vision
- chest pain or discomfort
- extra heartbeats
- a headache
- cold and clammy skin
- fast and shallow breathing
- swelling of your feet, legs, or hands purple spot on your skin caused by internal bleeding
- fast or abnormal heart rate or palpitations
- loss of appetite
- lower back, side, or stomach pain
- mental depression
- muscle pain or cramps
- Swelling of your feet or ankles
- Shortness of breath
- Nausea, fever, dark urine, loss of appetite
Drug Interactions of Irbesartan
Irbesartan may interact with following drugs, supplements, & may change the efficacy of drugs
- angiotensin-converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
- benzodiazepines (e.g., clonazepam, diazepam, lorazepam)
- beta-blockers (e.g., atenolol, metoprolol, propranolol)
- asthma medications (e.g., theophylline)
- nonsteroidal anti-inflammatory medications (NSAIDs; e.g., indomethacin, naproxen)
- oral diabetes medications (e.g., metformin, pioglitazone)
- monoamine oxidase (MAO) inhibitors (e.g., phenelzine, selegiline, )
- other beta-blockers (e.g., propranolol, metoprolol)
- macrolide antibiotics (e.g., clarithromycin, erythromycin)
- monoamine oxidase inhibitors (MAOIs; e.g., phenelzine, rasagiline, selegiline, )
- phosphodiesterase 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
Pregnancy & Lactation of Irbesartan
This drug has a black box warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning alerts doctors and patients about drug effects that may be dangerous. Don’t take this drug if you’re pregnant or plan to become pregnant. Irbesartan can harm or end your pregnancy. If you get pregnant while taking this drug, tell your doctor right away.
Because no information is available regarding the use of irbesartan breastfeeding-feeding, Irbesartan Milpharm is not recommended and alternative treatments with better established safety profiles during breast-feeding are preferable, especially while nursing a newborn or preterm infant. It is unknown whether irbesartan or its metabolites are excreted in human milk. Available pharmacodynamic/toxicological data in rats have shown excretion of irbesartan or its metabolites in milk
Irbesartan had no effect upon the fertility of treated rats and their offspring up to the dose levels inducing the first signs of parental toxicity.