8 Captopril Interactions to Be Aware Of
Key takeaways:
Captopril (Capoten) is an angiotensin-converting enzyme (ACE) inhibitor that treats high blood pressure and other heart-related conditions. Combining captopril with diuretics and other medications that can raise potassium levels raises your risk of side effects. Your prescriber will likely monitor you for these issues if you’re taking these medications together.
It’s best to avoid nonsteroidal anti-inflammatory drugs (NSAIDs), such as naproxen (Aleve), and angiotensin II receptor blockers (ARBs) if you’re taking captopril. These medications can raise the risk of kidney problems and other captopril side effects if they’re combined with it.
Combining captopril with mTOR inhibitors or Entresto can raise your risk of angioedema, a serious side effect. It’s best to avoid these combinations if possible. Captopril can raise lithium levels, so this combination should be closely monitored if it’s necessary.
Table of contents
Captopril (Capoten) is a medication that treats high blood pressure and other heart-related conditions. It belongs to a class of medications called angiotensin-converting enzyme (ACE) inhibitors.
If you’re taking captopril, knowing your dosage and what side effects to watch for can help you get the most from your medication. But knowing about captopril interactions is also key. Here, we’ll look at eight captopril interactions you should know about.
1. Diuretics
Diuretics, commonly known as “water pills,” help get rid of extra fluid in your body. Common diuretics include hydrochlorothiazide (Microzide) and furosemide (Lasix).
Like captopril, diuretics can lower your blood pressure. If the two medications are combined, your blood pressure may drop too low (hypotension). Symptoms of low blood pressure include dizziness, light-headedness, and weakness.
A sudden drop in blood pressure can also happen if you’re already taking a diuretic when you start captopril. This typically happens within the first hour of your first captopril dose. But after the first dose, it doesn’t usually happen again. Your prescriber may start you out on a small dose of captopril to help prevent this from happening. But it’s a good idea to take your first dose at home and remain seated for an hour or so afterward, just in case. If you feel faint after your first dose of captopril, be sure to let your prescriber know.
Some diuretics, such as spironolactone (Aldactone), can also increase potassium levels in the body. They’re commonly referred to as potassium-sparing diuretics. Captopril can also raise potassium levels. So taking these medications together is more likely to cause high potassium levels (hyperkalemia) along with low blood pressure. Symptoms of high potassium include feeling weak or having numbness or tingling sensations in your muscles.
Even though there’s an interaction between diuretics and captopril, they’re often prescribed at the same time. Your prescriber will likely keep an eye out for any signs that the combination is causing a problem, but be sure to let them know if symptoms of low blood pressure or high potassium appear.
2. NSAIDs
Nonsteroidal anti-inflammatory drugs (NSAIDs) are popular fever and pain relievers. Examples include ibuprofen (Motrin, Advil) and naproxen (Aleve).
NSAIDs can prevent captopril from lowering your blood pressure the way it should. They can also raise potassium levels in some cases. And combining NSAIDs and captopril can also raise your risk of kidney problems. In fact, taking captopril, an NSAID, and a diuretic together is sometimes called the “triple whammy” of kidney problems.
If you need a pain reliever, speak with a healthcare professional about safer options, such as acetaminophen (Tylenol).
3. Angiotensin II receptor blockers
Angiotensin II receptor blockers (ARBs) are medications that work in a very similar way to ACE inhibitors. Common ARBs include losartan (Cozaar) and valsartan (Diovan).
Captopril and ARBs both lower blood pressure and can raise potassium levels. The combination doesn’t have any benefits and raises the risk of side effects. So in most cases, you’ll take one or the other, but not both.
4. Lithium
Lithium (Lithobid) is a medication approved for bipolar disorder. Small changes in your blood levels of lithium can make a big difference in the side effects you experience.
Sodium affects how much lithium is removed from your body by the kidneys. Low sodium levels can increase lithium levels. And ACE inhibitors such as captopril tend to reduce the sodium in your body. So they can increase lithium levels and raise your risk of side effects or toxicity. Symptoms can include shaky hands, excessive thirst, and nausea. Severe symptoms include seizures, breathing troubles, and an irregular heartbeat.
If you need both lithium and captopril, your prescriber will adjust your lithium dose to make sure your levels stay in a safe range. But let them know if you notice a change in how you’re feeling while taking the medications together. And seek emergency care if severe symptoms of lithium toxicity occur.
5. Aliskiren
Aliskiren (Tekturna) is a blood pressure medication. It works in a similar way to both ACE inhibitors and ARBs. Taking aliskiren with captopril can increase your risk of low blood pressure, high potassium levels, and kidney problems. So the combination isn’t recommended, especially if you have a history of kidney problems or diabetes. These conditions raise the risk of serious side effects with the combination of captopril and aliskiren.
6. Medications that can raise potassium levels
As mentioned, high potassium levels are a possible captopril side effect. Taking other medications that raise your potassium levels, or consuming large amounts of potassium-rich foods, increases your risk for hyperkalemia.
We’ve already mentioned that ARBs, NSAIDs, and potassium-sparing diuretics can have this interaction. Other medications that can raise potassium levels include:
Potassium supplements (prescription and OTC)
Beta blockers
Spironolactone (Aldactone)
Cyclosporine (Sandimmune, Neoral)
Tacrolimus (Prograf)
Sulfamethoxazole / trimethoprim (Bactrim)
Medications aren’t the only thing that can increase potassium levels. Some salt substitutes and herbal supplements can raise potassium levels, too. Check with your pharmacist or prescriber before adding an OTC product to your medication regimen to make sure it’s safe for you.
7. Entresto
Entresto (sacubitril / valsartan) is a combination medication approved for heart failure. One of the ingredients in Entresto is valsartan — an ARB, which has an interaction risk we’ve previously discussed.
But sacubitril, the other ingredient in Entresto, has an added interaction with captopril. It can raise the risk of a serious side effect called angioedema. This side effect causes your face, mouth, and throat to swell, which can make breathing difficult. And it can be life-threatening in some cases. So it’s best to avoid combining captopril and Entresto.
8. Certain cancer and transplant medications
Mammalian target of rapamycin (mTOR) inhibitors are a type of immunosuppressant medication. They’re used to prevent organ rejection after a transplant and to treat certain cancers. Examples include sirolimus (Rapamune) and everolimus (Afinitor).
Taking an mTOR inhibitor with captopril can increase the risk of angioedema. Your healthcare team can help determine the risk versus benefit of combining these medications if both are needed.
When should you seek medical advice about captopril interactions?
A good first step to prevent captopril interactions is to be sure both your prescriber and pharmacist have your complete medication list. This can help them identify any possible issues in advance and make informed recommendations about your care.
If you experience side effects after you start taking another medication with captopril, let your healthcare team know. An interaction could be to blame.
Seek emergency care if you think you’re experiencing a serious side effect, including:
Angioedema: Symptoms include swelling in the face, throat, and mouth. It can also involve the lips and tongue.
High potassium levels: Symptoms include an irregular heartbeat (which can feel like heart palpitations) and muscle weakness.
Acute kidney injury: Symptoms include peeing less or not peeing, swelling in the ankles or legs, and trouble breathing.
The bottom line
Captopril (Capoten) is an angiotensin-converting enzyme (ACE) inhibitor that treats high blood pressure and other heart-related conditions. It has several drug interactions to consider.
Combining captopril with diuretics can raise your risk of low blood pressure. Some diuretics and other medications can also raise your potassium levels. Captopril can raise potassium levels, too, so if you take it with these medications your potassium level could become too high. Your prescriber will likely monitor for these issues if you’re taking these medications together. Angiotensin II receptor blockers (ARBs) can cause similar problems, but unlike diuretics, there’s no added benefit to taking them with captopril. So it’s best to avoid this combination.
Nonsteroidal anti-inflammatory drugs (NSAIDs) such as naproxen (Aleve) can raise the risk of kidney problems and make captopril less effective. So it’s best to avoid them if you’re taking captopril.
Captopril can raise lithium levels, so this combination should be closely monitored if it’s necessary. Combining captopril with mTOR inhibitors or Entresto can raise your risk of angioedema, a serious side effect. It’s best to avoid these combinations if possible.
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References
Albishri, J. (2013). NSAIDs and hypertension. Anaesthesia Pain & Intensive Care
Calvo Barbado, D. M., et al. (2022). Acute kidney injury associated with "triple whammy" combination: A protocol for a systematic review. F1000Research.
Camber Pharmaceuticals, Inc. (2023). Captopril- captopril tablet [package insert]. DailyMed.
Dreischulte, T., et al. (2015). Combined use of nonsteroidal anti-inflammatory drugs with diuretics and/or renin–angiotensin system inhibitors in the community increases the risk of acute kidney injury. Kidney International.
Duerr, M., et al. (2010). Increased incidence of angioedema with ACE inhibitors in combination with mTOR inhibitors in kidney transplant recipients. Clinical Journal of the American Society of Nephrology.
Hedya, S. A., et al. (2023). Lithium toxicity. StatPearls.
Kim, S., et al. (2007). Electrolyte and Acid-base disturbances associated with non-steroidal anti-inflammatory drugs. Electrolytes & Blood Pressure.
Kuenzli, A., et al. (2010). Meta-analysis of combined therapy with angiotensin receptor antagonists versus ace inhibitors alone in patients with heart failure. PLOS ONE.
National Kidney Foundation. (n.d.). Acute kidney injury (AKI).
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