Angiotension converting enzyme (ACE) inhibitors, such as lisinopril (Zestril), commonly cause a persistent dry cough. Angiotensin receptor blockers (ARB), like losartan (Cozaar), are less likely to cause this dry cough. Although these medication classes work in a similar fashion, ARBs do not inhibit kinase II which is thought to be responsible for the cough. Switching from lisinopril to losartan may help reduce the likelihood of developing a dry cough.


Before switching back to lisinopril, it may help to ensure that the losartan dose was sufficient. Increasing the dose may help lower your blood pressure without switching back to lisinopril. Also, other medications may be added to complement the losartan, even at a low dose. See below for a general idea of equivalent doses between losartan and lisinopril for high blood pressure:

 

 

Lisinopril

Losartan

Starting Dose

10 mg

50 mg

Usual dose range

20-40 mg/day

25-100 mg/day

Maximum Dose

80 mg

100 mg

Maximum Dose—renal dysfunction

40 mg

Dosage adjustment only if volume-depleted

 

If you and your doctor decide to switch to lisinopril from losartan, the following information may be helpful:

  • Losartan has a half-life of around 2-6 hours, including its active metabolite
  • Losartan should be cleared completely after 12-36 hours
  • Both medications have a similar mechanism of action in the kidneys.
  • Although this has not been extensively studied, it would make sense to start the lisinopril at the same time as your next losartan dose would have been due

  

Both ACE inhibitors and ARBs have cardiac protective effects outside of the impact on blood pressure. Although ACE inhibitors can cause a slight worsening in your serum creatinine in the near term, they are thought to be renal protective over the long term.


Both ACE inhibitors and ARBs are known to increase the risk of having hyperkalemia, or high potassium. The normal range for potassium is 3.5 to 5.0 mEq/L, but your physician may allow for variances to this range depending on your situation. Sometimes, potassium levels will be increased when beginning therapy, but may improve over time. The effect on both blood pressure and potassium levels is enhanced with higher doses. Hyperkalemia may also be associated with poor renal function and a serum creatinine test may be warranted to assess your kidney function.


Other common side effects of these medications include hypotension (low blood pressure) and dizziness. Angioedema, or swelling of the tongue, lips, and throat occur rarely with ACE inhibitors and ARBs, although the risk with ARBs is thought to be lower. This typically happens within the first week of treatment, but rarely occurs later in therapy.

Source: Zestril package insert, Cozaar package insert