1 Name of Medicine
Irbesartan/hydrochlorothiazide.
2 Qualitative and Quantitative Composition
Avsartan HCT 150/12.5 mg film-coated tablets. Film-coated tablets containing 150 mg of irbesartan and 12.5 mg of hydrochlorothiazide.
Avsartan HCT 300/12.5 mg film-coated tablets. Film-coated tablets containing 300 mg of irbesartan and 12.5 mg of hydrochlorothiazide.
Avsartan HCT 300/25 mg film-coated tablets. Film-coated tablets containing 300 mg of irbesartan and 25 mg of hydrochlorothiazide.
For the full list of excipients, see Section 6.1 List of Excipients.
3 Pharmaceutical Form
Avsartan HCT 150/12.5 mg tablets are peach coloured, capsule shaped, biconvex, film-coated tablets, approximately 14 mm long and 7 mm wide, debossed with 'IH' on one face and plain on other face.
Avsartan HCT 300/12.5 mg tablets are peach coloured, capsule shaped, biconvex, film-coated tablets, approximately 18 mm long and 9 mm wide debossed with 'IH2' on one face and plain on other face.
Avsartan HCT 300/25 mg tablets are brick red coloured, capsule shaped, biconvex, film-coated tablets, approximately 18 mm long and 9 mm wide, debossed with 'IH1' on one face and plain on other face.
4 Clinical Particulars
4.9 Overdose
Experience in adults exposed to irbesartan doses of up to 900 mg/day for 8 weeks revealed no toxicity. No specific information is available on the treatment of overdosage with irbesartan/hydrochlorothiazide. The patient should be closely monitored, and the treatment should be symptomatic and supportive, including fluid and electrolyte replacement. Irbesartan is not removed from the body by haemodialysis.
The most common signs and symptoms observed in adults exposed to hydrochlorothiazide are those caused by electrolyte depletion (hypokalemia, hypochloremia, hyponatremia) and dehydration resulting from excessive diuresis. If a cardiac glycoside (e.g. digoxin) or other antiarrhythmic drugs (e.g. sotalol) has also been administered, hypokalemia may accentuate cardiac arrhythmias. The degree to which hydrochlorothiazide is removed by haemodialysis has not been established.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).
5 Pharmacological Properties
5.3 Preclinical Safety Data
Genotoxicity. Irbesartan and the irbesartan/hydrochlorothiazide combination were not genotoxic in a series of assays for gene-mutagenic activity in bacterial and mammalian cells, and for clastogenic effects in vitro and in vivo. Hydrochlorothiazide alone was not genotoxic in a gene-mutation assay in bacterial cells, or in tests for clastogenic activity in vitro and in vivo. However, positive results were obtained in a mammalian cell assay for gene mutation (mouse lymphoma cell assay), and in two other tests (sister chromatid exchange assay in Chinese hamster ovary cells and non-disjunction assay in Aspergillus nidulans).
Carcinogenicity. The carcinogenic potential of irbesartan and hydrochlorothiazide in combination has not been evaluated in animal studies. However, the carcinogenic potential of irbesartan was assessed in two 104 week studies in mice and rats. No carcinogenic potential was observed in species at doses of up to 500 mg/kg/day (male rats) and 1000 mg/kg/day (mice and female rats). The AUC based exposure levels were 3 - 6 fold higher in mice, 3 fold higher in male rats and 25 fold higher in female rats than that of humans at the maximum recommended clinical dose of 300 mg/day. With hydrochlorothiazide two-year feeding studies in mice and rats uncovered no evidence of carcinogenic potential in female mice at doses up to approximately 600 mg/kg/day, or in male and female rats at doses up to approximately 100 mg/kg/day. The studies, however, uncovered equivocal evidence for hepato-carcinogenicity in male mice treated with hydrochlorothiazide at approximately 600 mg/kg/day.
6 Pharmaceutical Particulars
6.7 Physicochemical Properties
Irbesartan is a white to off-white crystalline powder. It is a relatively non-polar compound with a partition coefficient (octanol-water) of 10.1 at a pH of 7.4. Irbesartan is practically insoluble in water, sparingly soluble in methanol, slightly soluble in methylene chloride.
Hydrochlorothiazide is a white crystalline powder. It is slightly soluble in water but freely soluble in sodium hydroxide solution.
Irbesartan. 2-butyl-3-[(2'-(1H-tetrazol-5-yl) biphenyl-4-yl) methyl]-1,3-diazaspiro [4,4] non-1-en-4-one.
Irbesartan molecular formula of C25H28N6O.
Irbesartan molecular weight of 428.5.
Chemical structure.
https://stagingapi.mims.com/au/public/v2/images/fullchemgif/CSIRBESA.gif CAS number. 138402-11-6.
Hydrochlorothiazide. 6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide.
Molecular formula of C7H8ClN3O4S2.
Molecular weight of 297.7.
Chemical structure.
https://stagingapi.mims.com/au/public/v2/images/fullchemgif/CSHYDROC.gif CAS number. 58-93-5.
7 Medicine Schedule (Poisons Standard)
S4 - Prescription only medicine.
Summary Table of Changes
https://stagingapi.mims.com/au/public/v2/images/fulltablegif/AVSHCTST.gif