What are the possible side effects of Candesartan (Angiotensin II receptor antagonist) for hypertension?

Common Side Effects of Candesartan for Hypertension

Candesartan can cause hyperkalemia, dizziness, headache, and renal impairment as its most significant side effects, with special caution needed in patients with kidney disease. 1

Major Side Effects

Cardiovascular Effects

• Symptomatic hypotension, especially in volume-depleted patients 1
• Dizziness (reported in approximately 7% of patients) 2
• Postural hypotension, particularly in elderly patients 3

Renal Effects

• Impaired renal function, especially in patients with:
  • Renal artery stenosis
  • Chronic kidney disease
  • Severe heart failure
  • Volume depletion 1
• Increased risk of acute renal failure in susceptible individuals 1
• Requires monitoring of renal function periodically during treatment 1

Electrolyte Abnormalities

• Hyperkalemia (elevated potassium levels) 3, 1
  • Studies have shown an increased risk of hyperkalemia with ARBs like candesartan (HR 1.34; 95% CI: 1.03,1.74) 3
  • Particularly concerning in patients with heart failure or kidney disease 3
• Hypomagnesemia (low magnesium levels) (HR 1.57; 95% CI: 1.16,2.12) 3

Other Common Side Effects

• Headache (reported in about 6% of patients) 2
• Upper respiratory tract infection (approximately 5% of patients) 2, 4
• Back pain 4

Special Populations and Precautions

Pregnancy

• Contraindicated in pregnancy, especially during second and third trimesters 1
• Can cause fetal renal dysfunction, oligohydramnios, and neonatal morbidity 1
• Must be discontinued when pregnancy is detected 1

Renal Impairment

• Close monitoring required in patients with renal impairment 5
• Consider holding medication if:
  • Serum creatinine rises to >3.5 mg/dL
  • Potassium rises to >6.0 mmol/L
  • Signs of acute kidney injury appear 5
• Patients with bilateral renal artery stenosis are at particularly high risk 5

Diabetic Patients

• May require closer monitoring due to potential effects on renal function 3
• In diabetic patients with retinopathy, candesartan showed a non-significant trend toward reduced progression of retinopathy 3

Drug Interactions

• Increased risk of hyperkalemia when combined with:
  • Potassium-sparing diuretics
  • Potassium supplements
  • Salt substitutes containing potassium 1
• NSAIDs may reduce antihypertensive effect and increase risk of renal dysfunction 1
• Lithium levels may increase when used with candesartan 1
• Dual blockade with ACE inhibitors or aliskiren increases risks of hypotension, hyperkalemia, and renal dysfunction 1

Monitoring Recommendations

1. Check renal function and electrolytes before starting treatment
2. Monitor serum potassium regularly, especially in high-risk patients
3. Monitor blood pressure, particularly in the elderly (including standing BP)
4. Assess for signs of renal impairment periodically during treatment
5. Consider dose reduction in patients with moderate renal impairment 5

Tolerability Profile

Despite these potential side effects, clinical studies indicate that candesartan is generally well-tolerated:

• Adverse events are usually mild to moderate in severity 4
• Side effects are typically not dose-related 4, 6
• The overall tolerability profile is similar to placebo in many studies 4, 6
• Incidence of cough is lower than with ACE inhibitors 7

Understanding these potential side effects and appropriate monitoring can help manage patients on candesartan therapy effectively while minimizing risks.