Aliskiren: what it treats, how to take it, and side effects
Last updated September 7, 2026.
**Aliskiren is a prescription blood pressure medicine and the only direct renin inhibitor sold in the United States, marketed as Tekturna and as a generic.** It blocks renin, the first enzyme in the hormone chain that tightens blood vessels and makes your body hold onto salt and water, so vessels relax and pressure drops. The single most important safety point is pregnancy: medicines that act on this hormone system can injure or kill a developing baby, so aliskiren carries a boxed warning to stop it as soon as pregnancy is detected.
What does it treat?
Aliskiren is approved to treat high blood pressure (hypertension) in adults and in children 6 years and older who weigh at least 50 kg. Lowering blood pressure reduces the long-term risk of strokes, heart attacks, and kidney damage. High blood pressure usually causes no symptoms at all, which is why it is found on a cuff reading rather than by how you feel; some people notice headaches, dizziness, or nosebleeds when readings run very high. Aliskiren is rarely a first choice in the United States. Clinicians typically reach for it when standard options such as ACE inhibitors, ARBs, calcium channel blockers, or thiazide diuretics have not worked or were not tolerated. It also comes as a combination tablet with hydrochlorothiazide (Tekturna HCT), which pairs it with a water pill. Older combinations with valsartan and with amlodipine were withdrawn from the US market, so a pharmacy will not fill those.
How do you take it?
Aliskiren comes as 150 mg and 300 mg oral tablets taken once a day. The usual adult starting dose is 150 mg once daily, and if blood pressure is still above goal your doctor may raise it to 300 mg once daily. That 300 mg is the daily ceiling: higher doses do not lower blood pressure any further and cause more diarrhea. Most of the effect on your readings shows up within two weeks. Food matters more with this drug than with most blood pressure pills, because a high-fat meal cuts absorption sharply. Take it the same way every day, either always with a light meal or always on an empty stomach, and skip high-fat meals around your dose. Avoid grapefruit juice, which lowers the amount of drug your body absorbs. If you miss a dose, take it when you remember unless your next dose is close, then skip the missed one and go back to your schedule; never take two tablets to catch up. Stop aliskiren and call your doctor right away if you become pregnant or think you might be, if you faint or feel severely lightheaded, or if you have vomiting or diarrhea that keeps you from drinking normally, since dehydration can drop your pressure too far.
Side effects to know
- Common: The most common effect is diarrhea, and some people get dizziness or lightheadedness (especially in the first days or after a dose increase), headache, cough, tiredness, or a rash.
- Serious: Stop aliskiren and get emergency help for swelling of the face, lips, tongue, or throat, or trouble breathing or swallowing, which can signal angioedema. Also call your doctor promptly for fainting, muscle weakness or a slow or irregular heartbeat (which can mean high potassium), or a large drop in how much you are urinating, since all of these mean the drug needs to be stopped and your labs checked.
Who should not take it?
Do not take aliskiren if you are pregnant, and stop it and call your doctor the day you find out you are pregnant, because drugs acting on the renin-angiotensin system can harm a developing baby's kidneys and lungs in the second and third trimesters. If you could become pregnant, talk about birth control or a safer blood pressure medicine before you start. Aliskiren is not recommended while breastfeeding, since it is not known whether it passes into human milk. Do not combine it with an ACE inhibitor (such as lisinopril or enalapril) or an ARB (such as losartan or valsartan) if you have diabetes; that combination is contraindicated because it raises the risk of kidney failure, high potassium, and dangerously low blood pressure. The same combination is avoided if your kidney function is reduced (eGFR under 60). Do not use it with cyclosporine or itraconazole. Tell your doctor if you have kidney disease, are on dialysis, have high potassium, have had angioedema from any cause, are on a low-salt diet or water pills, or take potassium supplements, potassium-containing salt substitutes, spironolactone or other potassium-sparing diuretics, lithium, or regular NSAIDs like ibuprofen or naproxen, which can blunt the effect and strain the kidneys. Aliskiren is contraindicated in children under 2 years. There is no direct interaction with alcohol, but alcohol lowers blood pressure on its own and adds to dizziness, so keep intake light and stand up slowly.
When is it an emergency?
Call 911 for swelling of the lips, tongue, or throat, trouble breathing, hives with faintness, chest pain, or if someone collapses or cannot be woken. For a suspected overdose, call Poison Control at 1-800-222-1222 right away, even if the person seems fine; the main sign of too much aliskiren is blood pressure falling too far, which looks like severe dizziness, blurred vision, cold and clammy skin, a racing or very weak pulse, confusion, or fainting. Lie the person down and raise their legs while you call. Other drug-specific reasons to be seen the same day include passing very little urine or none, new swelling in the legs with rapid weight gain, or muscle weakness with a slow or skipping heartbeat, which can point to a potassium problem. Diarrhea that goes on for more than a day or two on this drug also deserves a call, since fluid loss can push your pressure and kidney function down together.
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Common questions
What is the maximum dose of aliskiren per day?
The ceiling is 300 mg once daily. Most people start at 150 mg once daily and move up to 300 mg only if blood pressure is still above goal after a couple of weeks. Doses above 300 mg were studied and did not lower blood pressure any further, but they did cause more diarrhea, so there is no reason to go higher. Aliskiren is a once-daily drug, so 300 mg means one 300 mg tablet, not two 150 mg tablets at different times unless your doctor specifically wrote it that way. Never take an extra tablet to make up for a missed dose.
Can I drink alcohol while taking aliskiren?
There is no direct chemical interaction between alcohol and aliskiren, so an occasional drink is not off-limits for most people. The practical problem is that alcohol lowers blood pressure and widens blood vessels on its own, so it stacks on top of what the medicine is already doing. That can make you lightheaded or unsteady, especially when you stand up quickly, in the first week of treatment, or after a dose increase. Heavy or regular drinking also pushes blood pressure up over time and makes readings harder to control. Keep it light, do not drink on an empty stomach, and stand up slowly afterward.
Is aliskiren safe during pregnancy or breastfeeding?
No. Aliskiren has a boxed warning for fetal toxicity and should be stopped as soon as pregnancy is detected. Drugs that block the renin-angiotensin system reduce blood flow through the developing kidneys, which can cause low amniotic fluid, poor lung and skull development, kidney failure in the newborn, and death. The risk is highest in the second and third trimesters, but the guidance is to switch off the drug immediately rather than wait. If you could become pregnant, plan a different blood pressure medicine with your doctor before you conceive. Aliskiren is also not recommended while breastfeeding, because it is not known whether it passes into human milk.
Do I have to take aliskiren with food?
What matters is consistency, not whether you use food. High-fat meals cut how much aliskiren your body absorbs by a large margin, so a tablet taken with a heavy fried meal delivers much less drug than the same tablet taken on an empty stomach. Pick one routine, either always on an empty stomach or always with the same kind of light meal, and stick to it every day so your blood pressure stays steady. Avoid pairing your dose with high-fat meals. Also skip grapefruit juice around your dose, since it lowers aliskiren levels.
What are the signs of an aliskiren overdose?
The main effect of too much aliskiren is blood pressure falling too far. That shows up as severe dizziness, blurred vision, feeling cold and clammy, a fast weak pulse or a slow one, confusion, and fainting. Call Poison Control at 1-800-222-1222 immediately for any suspected overdose, including an accidental double dose in a child, even if the person still looks well. While you wait, have them lie down with their legs raised. Call 911 instead if they collapse, cannot be woken, or are having trouble breathing. Aliskiren is not removed well by dialysis, so treatment is mainly fluids and support.
Which medicines interact with aliskiren?
The big one is combining aliskiren with an ACE inhibitor (lisinopril, enalapril, ramipril) or an ARB (losartan, valsartan, olmesartan). That pairing is contraindicated if you have diabetes and is avoided if your eGFR is under 60, because it raises the risk of kidney failure, high potassium, and low blood pressure. Do not take aliskiren with cyclosporine or itraconazole, which drive its levels up. Potassium supplements, salt substitutes containing potassium, and potassium-sparing diuretics such as spironolactone add to the potassium risk. Regular NSAIDs like ibuprofen and naproxen blunt the blood pressure effect and can worsen kidney function, especially if you are older or dehydrated. Aliskiren also raises lithium levels, so lithium doses need monitoring.