Irbesartan/ Hydrochlorothiazide

Registered South African indications: 

• Hypertension

Contraindications

• Hypersensitivity to the active ingredients or any of the excipients in this combination product
• Hypersensitivity to sulphonamide-derived substances
• Pregnancy
• Severe renal impairment
• Severe hepatic impairment
• Refractory hypokalaemia and hypercalcaemia

Cautions

• Breastfeeding
• Intravascular volume depletion
• Bilateral renal artery stenosis, stenosis of artery of single functioning kidney
• Kidney transplant
• Fixed cardiac output states
• Primary aldosteronism
• Diabetes mellitus
• Gout
• Cardiac failure
• Ischaemic cardiovascular disease
• Asthma
• Systemic lupus erythematosus
• Risk factors for acute-angle closure glaucoma

Forms avail. in SA and covered in this monograph: tab

Hypertension

Irbesartan/ Hydrochlorothiazide
150/ 12.5 (mg)
300/ 12.5 (mg)

• Oral (tab): 1 tab, dly

300/ 25 (mg)

• Oral (tab): 1 tab, dly; Max: 1 tab/24hrs

Not established for use in children

Recommendations for this combination product as per highest risk category when comparing individual active ingredients

Pregnancy

• FDA Pregnancy Category D (Irbesartan)

Breastfeeding

• Caution; not recommended (Irbesartan, Hydrochlorothiazide)

Renal Impairment

• Severe: Contraindicated

Hepatic Impairment

• Severe: Contraindicated

Elderly

• No dose adjustment recommended

Central Nervous System Disorders

• Dizziness
• Headache
• Vertigo
• Fatigue
• Weakness
• Lethargy
• Drowsiness
• Restlessness
• Seizures
• Paraesthesia

Cardiovascular Disorders

• Orthostatic hypotension
• Flushing
• Tachycardia
• Chest pain
• Syncope
• Oedema

Respiratory Disorders

• Cough

Gastrointestinal Disorders

• Nausea and vomiting
• Diarrhoea
• Dyspepsia
• Heartburn
• Constipation
• Intestinal ulceration

Hepatobiliary Disorders

• Jaundice hepatitis
• Abnormal liver function
• Cholestatic jaundice
• Pancreatitis

Genitourinary Disorders

• Impaired renal function
• Renal failure
• Sexual dysfunction

Endocrine and Metabolic Disorders

• Hypochloraemic alkalosis
• Hyponatremia
• Hypokalaemia
• Hyperglycaemia
• Hyperuricaemia
• Gout
• Hypomagnesaemia
• Anorexia
• Increased creatinine
• Increased creatine kinase

Musculoskeletal Disorders

• Musculoskeletal pain
• Arthralgia
• Myalgia
• Muscle cramps

Skin and Subcutaneous Tissue Disorders

• Rash
• Urticaria

Immune, Blood and Lymphatic System Disorders

• Hypersensitivity reactions 
• Leukocytoclastic vasculitis
• Thrombocytopaenia
• Granulocytopaenia
• Leucopenia
• Aplastic anaemia
• Haemolytic anaemia

Sensory Disorders

• Tinnitus
• Dry mouth
• Thirst
• Yellow vision

• Diuretics
• Antihypertensive agents
• Agents that increase/decrease serum potassium
• Lithium
• Non-steroidal anti-inflammatory drugs
• Digoxin
• Cholestyramine
• Colestipol
• Neuromuscular blocking agents
• Antidiabetic agents
• Central nervous system depressants
• Corticosteroids
• Corticotrophin
• Beta-2 agonists
• Adrenaline
• Probenecid
• Allopurinol
• Sulfinpyrazone
• Calcium salts
• Carbamazepine
• Beta blockers
• Diazoxide
• Cytotoxic agents
• Anticholinergic agents

• Renal function
• Electrolytes

Specific cases may require

• Serum potassium

Irbesartan
Irbesartan is a selective angiotensin-II receptor antagonist. Blockade of this receptor on vascular smooth muscle cells and in the adrenal cortex prevents binding of angiotensin-II and all its downstream effects. Thus irebesartan brings about a decrease in plasma aldosterone and a decrease in blood pressure. 

Hydrochlorothiazide
Hydrochlorothiazide acts primarily in the distal convoluted tubule where it inhibits sodium chloride transport. It competes for the chloride site and affects the electrolyte reabsorption by increasing sodium and chloride excretion. This reduces plasma volume indirectly and increases plasma renin activity, aldosterone secretion and urinary potassium loss.

COMBINATION PREPARATION

Irbesartan/ Hydrochlorothiazide

Tablet 150mg/12.5mg

• Co Approvel (Sanofi)
• Co-Irbewin (Zentiva) originator
• Isart Co (Zydus)

Tablet 300mg/12.5mg 

• Co Approvel (Sanofi)
• Co-Irbewin (Zentiva) orginator
• Isart Co (Zydus)

Tablet 300mg/25mg 

• Co-Irbewin (Sanofi)