A 45-year-old man with a history of depression brings a new prescription for Avalide to the pharmacy. The pharmacist should counsel the patient to:
Explanation
Avalide (Irbesartan/Hydrochlorothiazide) combines the angiotensin II receptor blocker irbesartan with the thiazide diuretic hydrochlorothiazide. It is indicated for the treatment of hypertension.
Avalide may be taken with or without food. The usual starting dose is 150/12.5 mg once daily. If additional blood pressure control is needed, the dose may be increased after 1 to 2 weeks to a maximum of 300/25 mg once daily.
Irbesartan and hydrochlorothiazide can lower blood pressure and cause symptomatic hypotension. Patients should inform their prescriber if they experience lightheadedness or fainting, particularly during the first days of treatment.Volume depletion caused by inadequate fluid intake, excessive sweating, vomiting, or diarrhea can further reduce blood pressure and increase the risk of dizziness or syncope.
Alcohol may intensify dizziness or hypotension, but complete avoidance is not universally required. Potassium supplements and potassium-containing salt substitutes should be used only under the prescriber's direction because irbesartan can increase serum potassium; however, hydrochlorothiazide may decrease it. Gastroesophageal reflux and worsening depression are not characteristic adverse effects of this combination.
Avalide carries a boxed warning for fetal toxicity. Drugs acting on the renin-angiotensin system can cause fetal injury or death; discontinue therapy as soon as pregnancy is detected.
Key Points:
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Monitor blood pressure, renal function, and serum electrolytes during therapy.
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NSAIDs may reduce the antihypertensive and diuretic effects and increase the risk of kidney injury, particularly in older or volume-depleted patients.
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Hydrochlorothiazide may increase uric acid, glucose, and calcium concentrations.
Exam Pearl: Administering Avalide in the morning may minimize nighttime urination from hydrochlorothiazide.
