The most prevalent side effect: The persistent dry cough
While multiple side effects are commonly associated with lisinopril, the persistent, dry, and irritating cough is often cited as the most well-known and is a frequent reason for discontinuing the medication. The incidence of this cough varies, with some reports suggesting it affects anywhere from 4% to 35% of patients. Unlike a cough from a respiratory infection, this is typically nonproductive and can significantly interfere with a patient's quality of life and sleep.
The mechanism behind the cough
The reason lisinopril and other ACE inhibitors cause this cough is due to their mechanism of action. These drugs inhibit the angiotensin-converting enzyme, which is also responsible for breaking down a substance called bradykinin. By blocking ACE, lisinopril causes an accumulation of bradykinin in the lungs and airways. The elevated levels of bradykinin are believed to irritate the nerve endings and stimulate the cough reflex. The cough can develop at any time, from within hours of the first dose to months after starting therapy, and it often resolves within a few weeks of stopping the medication. Women and non-smokers appear to have a higher risk of developing this side effect.
Other common side effects of lisinopril
Although the cough is infamous, other side effects are also very common and can sometimes be more prevalent depending on the patient's condition. For instance, in some studies of heart failure patients, low blood pressure (hypotension) was reported as more common than cough.
Dizziness and low blood pressure
As an antihypertensive medication, lisinopril's purpose is to lower blood pressure. However, it can sometimes lower it too much, especially when treatment is first initiated or the dose is increased. This can lead to symptoms such as dizziness, lightheadedness, and fatigue. Patients, particularly older adults, should be cautious of the risk of falls associated with dizziness. It is often recommended to stand up slowly from sitting or lying down to allow the body to adjust.
Elevated potassium (hyperkalemia)
Lisinopril can cause increased levels of potassium in the blood, a condition known as hyperkalemia. While often mild, severely high potassium levels can be life-threatening and cause irregular heartbeats. Regular blood tests are necessary to monitor potassium levels, especially for patients with kidney problems or diabetes, or those taking potassium-sparing diuretics. Patients should be advised to avoid potassium supplements and salt substitutes containing potassium chloride unless directed by a doctor.
Serious, but less common, side effects
While most side effects are manageable, some serious reactions can occur with lisinopril. These are rare but require immediate medical attention.
- Angioedema: This is a serious condition characterized by the rapid swelling of the face, lips, tongue, or throat and is caused by the same bradykinin accumulation that causes the cough. Angioedema can restrict breathing and become life-threatening. It can happen at any point during treatment, even years after starting the medication. Risk factors include being of Black descent, being female, and concurrent use of certain medications like NSAIDs.
- Severe skin reactions: Rare, but potentially life-threatening skin rashes and reactions, such as Stevens-Johnson syndrome, have been reported.
- Kidney and liver problems: Lisinopril can sometimes affect kidney function, which is why routine blood tests are part of the monitoring process. Liver damage is a rare but possible serious side effect.
Comparison of ACE Inhibitors and ARBs
If the dry cough from lisinopril becomes bothersome, a healthcare provider may recommend switching to a different type of blood pressure medication, such as an angiotensin II receptor blocker (ARB) like losartan. ARBs work differently in the body and are far less likely to cause a cough.
| Side Effect | Lisinopril (ACE Inhibitor) | Losartan (ARB) |
|---|---|---|
| Dry Cough | Common (incidence up to 35%) and often leads to discontinuation. | Much less likely (incidence similar to placebo in some studies). |
| Mechanism of Action | Inhibits the enzyme that breaks down bradykinin, leading to its accumulation. | Blocks the effect of angiotensin II without affecting bradykinin levels. |
| Dizziness/Hypotension | Common, especially when starting treatment or after a dose increase. | Common, as with all blood pressure medications. |
| Angioedema | A rare but serious side effect due to bradykinin build-up. | Rare; angioedema risk is significantly lower but still possible. |
| Drug Class | Angiotensin-Converting Enzyme (ACE) Inhibitor. | Angiotensin II Receptor Blocker (ARB). |
Managing lisinopril side effects
For patients taking lisinopril, recognizing and managing potential side effects is crucial for effective treatment. Here are some actionable steps:
- Do not stop taking lisinopril abruptly without consulting your doctor, as this can cause your blood pressure to increase suddenly.
- Report the dry cough to your healthcare provider. If it is persistent and bothersome, they may switch you to an alternative medication like an ARB.
- For dizziness or lightheadedness, rise slowly from a sitting or lying position. If it persists, talk to your doctor, who may adjust your dosage.
- Stay hydrated, as dehydration can exacerbate low blood pressure and dizziness.
- Avoid potassium supplements and salt substitutes that contain potassium unless your doctor advises otherwise, to prevent hyperkalemia.
- Seek immediate medical attention for any signs of angioedema, including swelling of the face, tongue, or throat, or difficulty breathing.
- Regularly monitor blood pressure and undergo scheduled blood tests to check kidney function and potassium levels.
Conclusion
While the persistent dry cough is the most distinct and often-cited side effect of lisinopril, patients should be aware of other common side effects like dizziness and the rarer, but more serious, angioedema. The reason for the cough is related to the drug's mechanism of action, and it can often be effectively managed by switching to an ARB. Ultimately, a proactive approach in communicating with your healthcare provider about any adverse reactions is the most important step for a safe and effective treatment plan.
