The indications of irbesartan and valsartan are both essential hypertension. From this perspective, there is no difference between the two. The difference is that the indications are beyond the instructions (beyond the indications indicated in the drug instructions).
Clinical research shows that irbesartan can significantly reduce proteinuria (microalbuminuria), especially for patients with hypertension complicated with microalbuminuria and hypertension complicated with diabetes. Proteinuria is one of the main symptoms of renal injury, which will cause renal failure over time and reduce all aspects of the body, especially immunity. Reducing proteinuria is helpful to delay the development of nephropathy and prevent its deterioration.
Valsartan can reverse ventricular remodeling, improve cardiac function and reduce the mortality of patients with heart failure, especially for patients with hypertension complicated with heart failure or myocardial infarction. A new drug for the treatment of heart failure —— Shakubatribine and Valsartan Sodium Tablets, which is composed of Shakubatribine and Valsartan from enkephalinase inhibitors, strongly proves the positive role of Valsartan in improving heart failure.
In other words, patients with hypertension who need to reduce proteinuria are more suitable for irbesartan; Valsartan is more suitable for patients who need cardiac function.
The bioavailability of irbesartan is 60%~80%, the plasma peak time is 1~ 1.5 hours, and the elimination half-life is1~15 hours. The bioavailability of valsartan is about 25%, the time to reach the peak of blood concentration is 2 hours, and the clearance half-life is about 9 hours. You may not be familiar with these professional details, so let's take a closer look.
Bioavailability refers to the speed and degree of drug absorption into human circulation. Generally speaking, the higher the bioavailability, the better. The peak time of plasma refers to the time when the plasma concentration reaches the peak after taking medicine, which reflects the speed of drug onset. Elimination of half-life refers to the time required for the drug concentration to drop to half of the highest blood drug concentration, and a long half-life indicates that the drug takes a long time to take effect.
From the point of view of pharmacokinetics, irbesartan is superior to valsartan in bioavailability, onset time and duration of drug action.
Irbesartan is mainly metabolized in the liver, where it is metabolized by cytochrome P4502C9. Valsartan is rarely metabolized in the liver, and is mainly excreted in the prototype form, 70% of which is excreted through the biliary tract and the rest through the kidney. What does this have to do with combination medication? We need to start with cytochrome P4502C9.
Cytochrome P450, CYP450 for short, is the main drug metabolizing enzyme in the liver. CYP450 is a large family, including many drugs and enzymes. We can understand these drugs and enzymes as a series of safe channels. After the drug enters the human body, it must go out through one or several channels. If multiple drugs pass through the same channel, they may interact with each other, leading to drug accumulation, reducing curative effect and increasing the risk of adverse reactions.
Many drugs take the 2C9 channel, including irbesartan. Caution should be taken when drugs with the same metabolic pathway are used together, while valsartan has less interaction with other drugs, so it is safer to use them together.
In a word, irbesartan and valsartan are both good drugs, and there is no absolute difference between them. The specific choice should be based on the actual situation of patients.