Aliskiren is a prescription medication used to manage high blood pressure, also known as hypertension. It is sold under brand names such as Tekturna and Rasilez. This drug belongs to a class of medications called direct renin inhibitors, distinguishing it from other common blood pressure treatments. By managing hypertension, aliskiren helps reduce the strain on the heart and arteries, which can lower the long-term risk of cardiovascular events like strokes and heart attacks.
Mechanism of Action
Aliskiren targets the Renin-Angiotensin-Aldosterone System (RAAS), a hormone system that regulates blood pressure and fluid balance. This system initiates when the kidneys release an enzyme called renin in response to low blood pressure or decreased blood volume. Renin starts a cascade of chemical reactions by converting a protein called angiotensinogen into angiotensin I. Angiotensin I is then converted into a powerful substance called angiotensin II.
Angiotensin II has multiple effects that increase blood pressure. It causes the smooth muscles in the walls of blood vessels to contract, leading to vasoconstriction. It also stimulates the release of another hormone, aldosterone, which causes the kidneys to retain sodium and water, further increasing blood volume and pressure.
Aliskiren binds directly to renin and inhibits its activity. By blocking renin at the very beginning of this process, aliskiren prevents the formation of angiotensin I and, consequently, angiotensin II. This unique point of intervention sets it apart from other classes of antihypertensive drugs. For example, Angiotensin-Converting Enzyme (ACE) inhibitors work by blocking the conversion of angiotensin I to angiotensin II, and Angiotensin II Receptor Blockers (ARBs) prevent angiotensin II from binding to its receptors. Aliskiren’s action leads to the relaxation of blood vessels and a reduction in blood pressure.
Potential Side Effects
Aliskiren can cause side effects, which range from common and mild to serious. Among the most frequently reported side effects is diarrhea. Patients may also experience symptoms such as headache, dizziness, or cold-like symptoms. These effects are often transient and may resolve as the body adjusts to the medication.
Some side effects are more serious and warrant immediate consultation with a healthcare provider. A severe allergic reaction known as angioedema can occur, with symptoms including swelling of the face, lips, tongue, or throat. This condition can obstruct breathing and requires emergency medical care. Aliskiren may also cause high levels of potassium in the blood, a condition called hyperkalemia, which can be dangerous.
Patients should also be aware of signs related to kidney function and blood pressure. Symptoms of kidney damage, such as a change in the amount or frequency of urination, should be reported to a doctor right away. The medication can also cause blood pressure to drop too low, a condition known as hypotension, leading to feelings of dizziness or faintness. If any of these serious side effects occur, seek medical advice promptly.
Proper Usage and Drug Interactions
Aliskiren is typically prescribed as an oral tablet taken once daily. Maintain a consistent routine, taking it at the same time each day. Patients should be consistent about taking aliskiren either with or without food, but they must avoid taking it with high-fat meals. High-fat foods can significantly decrease the absorption of the drug, reducing its ability to lower blood pressure.
Certain substances and medications can interact with aliskiren, potentially altering its effects or increasing the risk of adverse events. It is advisable to avoid grapefruit juice while taking this medication. Patients should inform their doctor about all prescription and over-the-counter drugs they are using, including supplements. Common drugs that can interact include nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, the antifungal medication itraconazole, and the immunosuppressant cyclosporine. Combining aliskiren with other medications that affect the Renin-Angiotensin-Aldosterone System, such as ACE inhibitors or ARBs, requires careful monitoring.
Important Safety Warnings
The U.S. Food and Drug Administration (FDA) has issued a boxed warning for aliskiren regarding its use during pregnancy. This is the FDA’s most serious type of warning. The medication can cause direct harm to a developing fetus, leading to injury or even death. Aliskiren is contraindicated in pregnancy, and it must be stopped as soon as a pregnancy is detected.
It should not be used by patients with diabetes who are also taking an ACE inhibitor or an ARB. This specific combination was found to increase the risk of serious complications, including kidney impairment, hypotension, and hyperkalemia. A trial was halted after these risks were identified in patients with diabetes and kidney issues.
A warning is also in place for using aliskiren with ACE inhibitors or ARBs in patients who have moderate to severe kidney impairment. This is defined by a glomerular filtration rate below 60 mL/min. Patients with pre-existing severe kidney disease or those who are breastfeeding should also avoid this medication.