Can I switch from telmisartan (Angiotensin II Receptor Antagonist)/Hydrochlorothiazide (HCTZ) (Diuretic) to losartan (Angiotensin II Receptor Antagonist)/HCTZ for hypertension treatment?

Switching from Telmisartan/HCTZ to Losartan/HCTZ for Hypertension

Yes, you can safely switch from telmisartan/HCTZ to losartan/HCTZ for hypertension treatment, as both medications are angiotensin II receptor blockers (ARBs) combined with the same diuretic. 1

Rationale for Switching

Both medications contain:

• An ARB (telmisartan or losartan) that blocks angiotensin II receptors
• Hydrochlorothiazide (HCTZ), a thiazide diuretic that increases sodium excretion

The 2017 ACC/AHA guidelines recognize both telmisartan and losartan as effective ARBs for hypertension management, with both listed as primary agents in their recommended oral antihypertensive drugs table 1.

How to Switch

1. Direct switch approach: Since both medications contain the same diuretic (HCTZ) and ARBs with similar mechanisms of action, you can typically switch directly from one to the other at equivalent doses:

   • Telmisartan 40mg/HCTZ 12.5mg → Losartan 50mg/HCTZ 12.5mg
   • Telmisartan 80mg/HCTZ 12.5mg → Losartan 100mg/HCTZ 12.5mg

2. Monitor blood pressure: Check your blood pressure within 2-4 weeks after switching to ensure adequate control 1

Efficacy Considerations

It's important to note that some studies suggest telmisartan may provide slightly better 24-hour blood pressure control than losartan:

• Telmisartan has a longer half-life (24 hours) compared to losartan (6-9 hours) 2
• Research shows telmisartan may provide better blood pressure control during the early morning hours compared to losartan/HCTZ 3, 4

However, losartan/HCTZ is still an effective option for hypertension management and is FDA-approved for this indication 5.

Special Considerations

• Gout risk: Both medications contain HCTZ, which can increase uric acid levels. If you have a history of gout, consider discussing with your doctor about potentially switching to an ARB without HCTZ 1

• Dosing frequency: Losartan may require twice-daily dosing at higher doses, while telmisartan is typically once-daily 1

• Cost and availability: Losartan/HCTZ is often more widely available as a generic combination and may be less expensive than telmisartan/HCTZ

Potential Benefits of Losartan

Losartan has been specifically mentioned in guidelines for certain conditions:

• The 2020 ACR guidelines conditionally recommend choosing losartan preferentially as an antihypertensive when feasible for patients with gout 1
• The EULAR guidelines note losartan's modest uricosuric effects, which may be beneficial for patients with gout 1

Conclusion

The switch from telmisartan/HCTZ to losartan/HCTZ is reasonable and safe. While telmisartan may offer slightly better 24-hour coverage based on pharmacokinetics, losartan/HCTZ is an effective alternative that may have advantages in terms of cost, availability, or specific patient factors like gout management.