Valsartan

Valsartan is a blood pressure-lowering drug and belongs to the group of angiotensin II receptor blockers, which are used alone or in combination with other active ingredients to treat high blood pressure and reduce cardiovascular mortality after a heart attack (myocardial infarction).

Medicines containing valsartan require a prescription in Germany, Austria, Switzerland and other European countries.

Applications and indications

Valsartan is indicated for the treatment of hypertension to reduce the risk of fatal and non-fatal cardiovascular events, primarily strokes and heart attacks. It is also indicated for the treatment of heart failure (NYHA Class II-IV) and left ventricular dysfunction or failure following myocardial infarction when the use of an angiotensin-converting enzyme inhibitor (ACE inhibitor) is not appropriate.

The dosage of the drug is usually between 80 and 160mg daily, with a maximum of 320mg. Valsartan is often dosed lower initially to identify the correct dosage in a few iterations. Blood pressure is often measured by the patient during therapy to ensure proper adjustment of the drug.

Valsartan is most commonly administered as a tablet, but is also available as a solution.

Frequently, valsartan is used in dual combination preparations with

• Hydrochlorothiazide (HCT), a diuretic diuretic
• Sacubitril, a neprilysin inhibitor

or in a triple combination preparation with

• Hydrochlorothiazide (HCT) and amlodipine, a calcium channel blocker.

History

Losartan, the first sartan developed and thus a very similar agent, was patented in 1991 and first marketed in the United States in 1995. Later, valsartan was also developed, which has better efficacy and a longer duration of action.

Valsartan contamination in 2018.

In 2018, it became known that Chinese manufacturer Zhejiang Huahai Pharmaceutical circulated contaminated valsartan in numerous batches of its generic production. The European Medicines Agency (EMA) determined that the contamination with the carcinogenic substance N-nitrosodimethylamine could cause 1 in 5,000 additional patients to develop cancer. As a result, numerous generics produced in China with the active ingredient valsartan had to be withdrawn from the market. Preparations produced in Europe were not affected by the contamination.

Pharmacodynamics/Mechanism of action

Valsartan blocks the action of the endogenous substance angiotensin II, which constricts blood vessels and stimulates aldosterone release, thereby lowering blood pressure. The substance itself binds to the target receptor (angiotensin type I receptor), thereby preventing angiotensin II from binding to AT1. Thus, valsartan is an AT1 antagonist. Valsartan, unlike ACE inhibitors, does not affect bradykinin metabolism, which prevents the occurrence of irritable cough during use.

Pharmacokinetics

After oral administration, the antihypertensive effect of valsartan sets in within approximately 2 hours. Blood plasma concentrations peak within 2-6 hours in most patients. Consumption of food prior to ingestion reduces the availability of orally administered valsartan by approximately 40% and peak plasma concentrations by approximately 50%. The drug enters the blood predominantly through the intestine. Bioavailability is low, ranging from 25% (tablets) to 40% (solutions) depending on the dosage form.

Valsartan is highly bound to serum proteins (95%), mainly to serum albumin.

Valsartan, when administered orally, is excreted primarily in the feces (approximately 83% of the dose) and to a lesser extent in the urine (approximately 13% of the dose).

Drug Interactions

Interactions may occur in combination with other agents,

• Other inhibitors of the renin-angiotensin system may increase the risk of low blood pressure, kidney problems, and hyperkalemia.
• Potassium-sparing diuretics, potassium supplements, and potassium-containing salt substitutes may increase the risk of hyperkalemia.
• NSAIDs may increase the risk of kidney problems and interfere with antihypertensive effects.
• Valsartan may increase blood concentrations of lithium, which should result in constant blood level monitoring when taken concomitantly. Because concomitant administration of lithium and ACE inhibitors may increase blood lithium concentrations and lithium toxicity, medical monitoring is also recommended with valsartan.
• Valsartan and other angiotensin-dependent blood pressure medications may interact with the antibiotics co-trimoxazole or ciprofloxacin and increase the risk of sudden cardiac death.

Contraindications and precautions

• Concurrent use with the renin inhibitor aliskiren
• Patients with renal disease should not take valsartan
• Pregnancy
• Nursing mothers should not take valsartan.

Side effects

The frequency of side effects depends on the way the drug is used.

Heart failure

• dizziness
• low blood pressure
• diarrhea (diarrhea)
• joint pain
• fatigue
• back pain

high blood pressure

• Viral infections
• Fatigue
• Abdominal pain
• Headache
• Dizziness
• Upper respiratory tract infection
• Cough
• diarrhea
• rhinitis/sinusitis
• Nausea
• Pharyngitis
• Edema
• joint pain (arthralgia)

Pregnancy and lactation

Valsartan should not be taken in the second and third trimesters as it may cause harm to the unborn child. No information is available on its use during lactation. Therefore, the use of valsartan during breastfeeding is strongly discouraged. During pregnancy, the use of alpha-methyldopa or metoprolol is recommended instead.