Arbitan Plus150 mg+12.5 mg

Arbitan Plus is a fixed-dose combination of an angiotensin II receptor blocker (ARB) and a thiazide diuretic, indicated for the following:

Established/FDA-approved use

• Hypertension: Treatment of high blood pressure in adults whose blood pressure is not adequately controlled on monotherapy with either irbesartan or hydrochlorothiazide alone, or in patients who are expected to require multiple drugs to reach their blood pressure goal. Arbitan Plus is not indicated for initial therapy of hypertension.

Arbitan Plus lowers blood pressure but has not been specifically studied for reduction of cardiovascular morbidity and mortality; such benefits are inferred from the individual components used in other trials.

Each tablet of Irbesartan + Hydrochlorothiazide contains two active ingredients:

• Irbesartan - an angiotensin II receptor blocker (ARB), commonly available in strengths such as 150 mg or 300 mg.
• Hydrochlorothiazide - a thiazide diuretic, commonly available in strengths such as 12.5 mg or 25 mg.

Common combination strengths include 150 mg/12.5 mg, 300 mg/12.5 mg, and 300 mg/25 mg tablets.

Arbitan Plus is an oral fixed-dose combination antihypertensive medicine that pairs irbesartan, an angiotensin II receptor blocker (ARB), with hydrochlorothiazide, a thiazide-type diuretic. The two agents work through complementary mechanisms to produce a greater blood-pressure-lowering effect than either drug alone.

Arbitan Plus is used once daily as add-on or combination therapy for hypertension that is not adequately controlled by a single agent.

Arbitan Plus belongs to the therapeutic class of combination antihypertensive agents, specifically an Angiotensin II Receptor Blocker (ARB) combined with a Thiazide Diuretic.

Irbesartan + Hydrochlorothiazide combines two agents with complementary antihypertensive mechanisms:

Irbesartan (ARB)

Irbesartan selectively blocks the binding of angiotensin II to the AT1 receptor found in vascular smooth muscle and the adrenal gland. This blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II, resulting in vasodilation and reduced blood pressure, without affecting the bradykinin pathway.

Hydrochlorothiazide (thiazide diuretic)

Hydrochlorothiazide inhibits sodium and chloride reabsorption in the distal convoluted tubule of the nephron, increasing excretion of sodium, chloride, and water, and secondarily promoting potassium and magnesium excretion. The resulting reduction in plasma volume contributes to the antihypertensive effect.

Used together, the two components produce an additive reduction in blood pressure; hydrochlorothiazide-induced activation of the renin-angiotensin system is blunted by irbesartan, which also helps offset thiazide-induced hypokalemia to some degree.

Arbitan Plus is taken orally, once daily, with or without food. Swallow the tablet whole with a glass of water. Try to take it at the same time each day to maintain consistent blood pressure control. Do not stop taking Arbitan Plus suddenly without consulting a physician.

Arbitan Plus has the following well-documented clinically significant interactions:

• Dual blockade of the renin-angiotensin system (ACE inhibitors, other ARBs, or aliskiren): increases the risk of hypotension, hyperkalemia, and renal impairment. Combination with aliskiren is contraindicated in patients with diabetes.
• NSAIDs (including selective COX-2 inhibitors): may reduce the antihypertensive and diuretic effect of Arbitan Plus and can worsen renal function, particularly in volume-depleted or elderly patients.
• Potassium-sparing diuretics, potassium supplements, or salt substitutes containing potassium: may increase the risk of hyperkalemia when combined with irbesartan's component.
• Lithium: both ARBs and thiazides reduce lithium clearance, increasing the risk of lithium toxicity; concurrent use requires close monitoring of lithium levels.
• Other antihypertensives, alcohol, barbiturates, or narcotics: may potentiate hypotensive effects, especially orthostatic hypotension.
• Antidiabetic agents (insulin or oral hypoglycemics): hydrochlorothiazide can raise blood glucose, sometimes requiring dose adjustment of antidiabetic therapy.
• Cholestyramine and colestipol resins: reduce absorption of hydrochlorothiazide; Arbitan Plus should be taken well before or after these resins.
• Corticosteroids or ACTH: may intensify electrolyte depletion, particularly hypokalemia.
• Digoxin: thiazide-induced hypokalemia or hypomagnesemia increases the risk of digoxin toxicity.

Most people tolerate Arbitan Plus well. Reported side effects include:

Common

• Dizziness, fatigue, headache
• Musculoskeletal pain
• Nausea, upset stomach, diarrhea
• Mild increase in blood urea nitrogen and serum creatinine

Less common but important

• Orthostatic hypotension, especially in volume-depleted patients
• Electrolyte disturbances (hypokalemia, hyponatremia, hyperkalemia, hypomagnesemia)
• Elevated uric acid, precipitation of gout attacks
• Hyperglycemia and altered glucose tolerance

Rare but serious

• Angioedema (swelling of face, lips, tongue, throat)
• Acute renal failure
• Acute myopia and acute angle-closure glaucoma (thiazide-associated, usually within hours to weeks of starting)
• Photosensitivity reactions and other skin reactions
• Blood dyscrasias (rare, thiazide-associated)
• Pancreatitis (rare)

Seek urgent medical attention for signs of angioedema, severe dizziness/fainting, or eye pain with vision changes.

Pregnancy

Arbitan Plus is contraindicated during pregnancy. Drugs that act directly on the renin-angiotensin system, such as the irbesartan component, can cause injury and even death to the developing fetus when used in the second and third trimesters, including fetal renal failure, oligohydramnios, hypotension, skull hypoplasia, and death. If pregnancy is detected, Arbitan Plus should be discontinued as soon as possible and the patient switched to an alternative antihypertensive as advised by her physician.

Lactation

It is not known whether irbesartan is excreted in human breast milk; hydrochlorothiazide is excreted into breast milk in small amounts. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue breastfeeding or discontinue Arbitan Plus, taking into account the importance of the drug to the mother; consult a physician before use while breastfeeding.

Boxed warning: Arbitan Plus can cause fetal injury and death when used during pregnancy; discontinue as soon as pregnancy is detected (see Pregnancy and Lactation).

Volume/salt depletion

Patients with volume or salt depletion (e.g., from prior diuretic therapy, vomiting, diarrhea, or restricted salt intake) may experience symptomatic hypotension after starting Arbitan Plus; correct volume depletion before initiating therapy or start under close medical supervision.

Renal impairment and renal artery stenosis

Use with caution in patients with renal artery stenosis (unilateral or bilateral), as changes in renal function including acute renal failure may occur. Monitor renal function periodically, particularly in patients with pre-existing kidney disease.

Electrolyte imbalance

Arbitan Plus can cause hyperkalemia (from the irbesartan component) or hypokalemia and hyponatremia (from the hydrochlorothiazide component); the net effect on serum potassium varies between patients and should be monitored periodically, especially in the elderly, in renal impairment, and in diabetics.

Diabetes and gout

Thiazide therapy may worsen glycemic control in diabetic patients and may precipitate gout attacks in patients with a history of gout or hyperuricemia by raising serum uric acid.

Hepatic impairment

Use thiazides with caution in patients with hepatic impairment, as minor alterations in fluid and electrolyte balance may precipitate hepatic coma.

Other

Thiazides may cause photosensitivity, and can rarely cause acute angle-closure glaucoma or acute transient myopia requiring prompt discontinuation and medical attention. Lithium should generally not be co-administered (see Interactions).

Overdose with Arbitan Plus may cause pronounced hypotension, dizziness, and dehydration or electrolyte imbalance from the diuretic component, and tachycardia or bradycardia. There is no specific antidote.

If overdose is suspected, seek immediate medical attention or contact a poison control center/emergency services right away. Management is supportive, generally involving monitoring of vital signs and fluid/electrolyte status; do not attempt home treatment.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

Pregnant women

Contraindicated; see Pregnancy and Lactation.

Breastfeeding women

Use only if clearly needed, weighing benefit against potential infant risk; see Pregnancy and Lactation.

Pediatric patients

Safety and efficacy of Arbitan Plus have not been established in children. It is generally not recommended for use in the pediatric population.

Elderly patients

No dosage adjustment is generally required based on age alone, but elderly patients may be more susceptible to hypotension and electrolyte disturbances; use with routine monitoring.

Renal impairment

Not recommended in severe renal impairment (creatinine clearance below approximately 30 mL/min); see Dosage and Administration.

Hepatic impairment

Use with caution; see Dosage and Administration and Precautions and Warnings.

Arbitan Plus is generally used long-term for ongoing blood pressure control, as hypertension is a chronic condition. Duration of therapy is determined by the prescribing physician based on blood pressure response and tolerability; Arbitan Plus should not be stopped abruptly without medical advice.

Irbesartan + Hydrochlorothiazide is classified as a combination of an Angiotensin II Receptor Blocker (ARB) and a Thiazide Diuretic, used together as an antihypertensive.

Irbesartan + Hydrochlorothiazide combines two complementary mechanisms of blood pressure lowering:

• Irbesartan blocks the AT1 angiotensin II receptor, preventing angiotensin II-mediated vasoconstriction and aldosterone release, leading to vasodilation and reduced blood pressure.
• Hydrochlorothiazide inhibits sodium/chloride reabsorption in the distal renal tubule, increasing sodium and water excretion, reducing plasma volume, and lowering blood pressure.

The combination provides an additive antihypertensive effect greater than either agent alone.

Category D (as classified for drugs acting on the renin-angiotensin system, per legacy FDA pregnancy categories) - evidence of human fetal risk; contraindicated in pregnancy.

Safety and efficacy of Arbitan Plus have not been established in pediatric patients. It is not recommended for use in children and adolescents due to insufficient clinical data.