Losartan is not a nitrate. It belongs to a completely different class of medications called angiotensin receptor blockers (ARBs). The two drug classes work through different biological pathways, treat different conditions, and carry different side effects. If you’ve been asked whether you take nitrates, perhaps before a medical procedure or when starting a new medication, losartan does not fall into that category.
How Losartan Works
Losartan lowers blood pressure by blocking a hormone called angiotensin II from binding to receptors on your blood vessels. Angiotensin II normally causes blood vessels to tighten, so blocking it allows vessels to relax and blood pressure to drop. The drug is over 10,000 times more selective for one specific receptor subtype (AT1) than another, which is what makes it a targeted therapy rather than a blunt-force one.
Losartan is a first-line treatment for high blood pressure, typically prescribed at 50 to 100 mg per day. The 2025 AHA/ACC guidelines also recommend ARBs like losartan for people with chronic kidney disease, diabetes with kidney involvement, peripheral artery disease, and certain types of heart failure. It’s often used as an alternative when someone can’t tolerate a closely related class of drugs called ACE inhibitors.
How Nitrates Work
Nitrates lower blood pressure through an entirely different mechanism. They donate nitric oxide, a molecule that relaxes smooth muscle in blood vessel walls. Their strongest effect is on veins, which expand to hold more blood. This reduces the amount of blood returning to the heart, lightening the heart’s workload and cutting its oxygen demand. At higher doses, nitrates also widen coronary arteries, improving blood flow to areas of the heart that aren’t getting enough.
The most common nitrate medications are nitroglycerin, isosorbide mononitrate, and isosorbide dinitrate. Their primary job is treating or preventing chest pain (angina), not managing chronic high blood pressure. An AHA scientific statement notes that nitrates “have generally not been shown to be of use in the management of hypertension.” They’re situational tools for heart-related chest pain and acute coronary events, not everyday blood pressure control.
Why the Distinction Matters
The reason this question comes up so often is practical: nitrates have a well-known, dangerous interaction with erectile dysfunction medications like sildenafil. Combining the two can cause a severe, potentially fatal drop in blood pressure. If a doctor or pharmacist asks whether you take nitrates before prescribing one of these drugs, they need to know about nitroglycerin or isosorbide, not losartan. Losartan does not trigger the same interaction.
That said, losartan still lowers blood pressure, and combining it with other blood-pressure-lowering substances requires caution. When losartan is used alongside sodium nitrite (a related compound sometimes used in clinical settings), the interaction is rated as major because both reduce blood pressure and together they can cause dangerously low levels. This isn’t the same as the nitrate-sildenafil problem, but it’s a reminder that any combination of blood pressure medications needs careful management.
Different Conditions, Different Drugs
The simplest way to keep these apart is by what they’re prescribed for. Losartan is a long-term, daily medication for high blood pressure, kidney protection, and certain cardiovascular conditions. Nitrates are primarily short-term or as-needed treatments for chest pain caused by reduced blood flow to the heart. There is some overlap in heart failure management, where both classes can play a role, but they serve different functions even in that context.
For stable angina specifically, ARBs like losartan are recommended when the patient also has high blood pressure, diabetes, reduced heart function, or kidney disease. Nitrates are recommended for direct symptom relief of chest pain, especially when other options like beta-blockers aren’t suitable. The two can be prescribed to the same patient for different reasons, but one never substitutes for the other.
Side Effects Compared
The side effect profiles reinforce how different these medications are. Losartan’s most common side effects include dizziness, headaches, nausea, vomiting, diarrhea, and joint or muscle pain. Over the long term, it can affect kidney function and raise potassium levels, which is why doctors monitor bloodwork periodically. Serious but rare reactions include liver problems, inflamed pancreas, and blood disorders.
Nitrates are notorious for causing headaches, often intense ones, because the same blood vessel relaxation that helps the heart also dilates vessels in the head. They can cause flushing, dizziness, and drops in blood pressure when you stand up. A key concern with nitrates is tolerance: the body can become less responsive to them over time, which is why doctors often recommend a “nitrate-free” window each day to maintain effectiveness. Losartan does not have this tolerance issue and works consistently with daily use.