Lotrel is a prescription medication used to treat high blood pressure (hypertension). It combines two active ingredients, amlodipine and benazepril, into a single capsule. Each drug lowers blood pressure through a different mechanism, and clinical trials show the combination produces effects that are additive and, in some cases, greater than what either drug achieves alone.
How Lotrel Lowers Blood Pressure
Lotrel works by targeting two separate systems that regulate blood pressure. Amlodipine is a calcium channel blocker. It relaxes the smooth muscle in your artery walls by preventing calcium from entering those cells, which widens the arteries and reduces the resistance your heart pumps against. The result is a direct drop in blood pressure.
Benazepril is an ACE inhibitor. It blocks an enzyme that produces a substance called angiotensin II, one of the body’s most powerful blood vessel constrictors. With less angiotensin II circulating, your blood vessels relax and open up. At the same time, benazepril reduces levels of aldosterone, a hormone that tells your kidneys to hold onto sodium and water. Lower aldosterone means less fluid volume in your bloodstream, which also brings pressure down.
Because these two drugs attack blood pressure from completely different angles, combining them in one pill often works better than raising the dose of a single medication. This two-pronged approach is why Lotrel is commonly prescribed when one blood pressure drug alone isn’t enough to reach a healthy target.
How Much It Lowers Blood Pressure
In FDA-reviewed clinical trials, Lotrel produced meaningful reductions in both the top number (systolic) and bottom number (diastolic) of a blood pressure reading. Patients taking the higher-strength combination (10/20 mg) saw an average systolic drop of about 22 points and a diastolic drop of about 16 points. The lower-strength version (5/20 mg) performed similarly, with systolic pressure falling around 20 points and diastolic about 15 points. By comparison, patients on placebo saw drops of only about 5 points systolic and 5 points diastolic. Both strengths were statistically significantly more effective than placebo.
Available Strengths
Lotrel capsules come in six combinations, listed as the amlodipine dose followed by the benazepril dose: 2.5/10 mg, 5/10 mg, 5/20 mg, 5/40 mg, 10/20 mg, and 10/40 mg. Your prescriber typically starts at a lower strength and adjusts upward if your blood pressure doesn’t reach the target. Having multiple dose options makes it easier to fine-tune the medication without switching to a different drug entirely.
Common Side Effects
Most people tolerate Lotrel well. In placebo-controlled trials, the most frequently reported side effects were:
- Cough: 3.3% of patients. This is a well-known effect of ACE inhibitors like benazepril. It’s typically a dry, persistent cough that doesn’t produce mucus. For some people it’s mild enough to live with; for others, it’s a reason to switch medications.
- Swelling (edema): 2.1% of patients. This usually shows up as puffiness in the ankles or feet and comes from the amlodipine component. Interestingly, the benazepril in Lotrel may actually reduce the ankle swelling that amlodipine causes on its own, which is one practical benefit of the combination.
- Dizziness: 1.3% of patients. This can happen especially when you stand up quickly, since the medication is actively lowering your blood pressure. It tends to improve as your body adjusts over the first few weeks.
Who Should Not Take Lotrel
Lotrel carries an FDA boxed warning, the most serious type, regarding use during pregnancy. Drugs that act on the same system as benazepril can cause injury and even death to a developing fetus, particularly in the second and third trimesters. If you become pregnant while taking Lotrel, you should stop the medication as soon as possible.
People with a history of angioedema, a potentially dangerous swelling of the face, lips, tongue, or throat, should not take Lotrel. This reaction is linked to the ACE inhibitor component and can recur in anyone who has experienced it before, whether from a previous blood pressure medication or from another cause. Lotrel is also not appropriate for people with diabetes who are already taking aliskiren, another type of blood pressure drug, because the combination raises the risk of kidney problems and dangerously high potassium levels.
Interactions to Be Aware Of
Because benazepril reduces aldosterone, it can cause your body to retain potassium. Taking Lotrel alongside potassium supplements, salt substitutes (which often contain potassium chloride), or potassium-sparing diuretics can push potassium levels too high. Elevated potassium doesn’t always cause noticeable symptoms, but it can lead to dangerous heart rhythm changes, so your doctor will likely check your potassium through periodic blood work.
Lithium, a medication used for bipolar disorder, can build up to toxic levels when taken with ACE inhibitors. If you take lithium, your prescriber will want to monitor your lithium levels more closely while you’re on Lotrel. NSAIDs, the class of pain relievers that includes ibuprofen and naproxen, can also blunt Lotrel’s blood pressure-lowering effect and may increase the risk of kidney problems when combined with ACE inhibitors, particularly in people who are already dehydrated or have existing kidney issues.
What to Expect While Taking Lotrel
Lotrel is taken once daily by mouth, and most people notice the full blood pressure effect within a couple of weeks. It’s designed to provide 24-hour coverage, so consistent daily timing matters. Missing doses or stopping abruptly can cause your blood pressure to rebound.
Your prescriber will likely order blood work before starting Lotrel and periodically afterward to check kidney function and potassium levels. These are routine checks related to the ACE inhibitor component, not signs that anything is wrong. If you experience a persistent dry cough, significant ankle swelling, or episodes of dizziness that don’t improve after the first few weeks, those are worth bringing up at your next appointment, as a dose adjustment or medication change can usually resolve them.