Pharma Jogot
Valsartan is a medication used to treat high blood pressure, heart failure, and diabetic kidney disease. It belongs to a class of medications referred to as angiotensin II receptor blockers (ARBs). It is a reasonable initial treatment for high blood pressure. It is taken by mouth. Versions are available as the combination valsartan/hydrochlorothiazide, valsartan/amlodipine, valsartan/amlodipine/hydrochlorothiazide, or valsartan/sacubitril.
Valsartan was patented in 1990 and came into medical use in 1996. It is available as a generic medication. In 2020, it was the 123rd most commonly prescribed medication in the United States, with more than 5 million prescriptions.
Indications
Valsartan is indicated:
- For hypertension
- To reduce hospitalizations in patients with congestive heart failure
- To reduce death in patients who developed congestive heart failure after myocardial infarction
Pharmacology
Valsartan is an oral medication that belongs to a class of drugs called angiotensin receptor blockers (ARBs). It is an orally active and specific angiotensin II antagonist acting on the AT1 subtype. Angiotensin’s attachment to the receptors causes the blood vessels to narrow (vasoconstrict) which leads to an increase in blood pressure (hypertension). Valsartan blocks the angiotensin II receptor. By blocking the action of angiotensin, Valsartan dilates blood vessels and reduces blood pressure without affecting pulse rate. Valsartan has a much greater affinity (about 20,000-fold) for the AT1 receptor than for the AT2 receptor. It does not bind or block other hormone receptors or ion channels known to be important in cardiovascular regulation.
Dosage
Hypertension: The usual dose of Valsartan is 80 to 160 mg once daily. The maximum dose is 320 mg daily. Maximum blood pressure reduction occurs within 4 weeks.
Heart failure: The usual dose is 40 mg twice daily and may be increased to 80-160 mg twice daily.
Post-Myocardial Infarction: The initial dose after myocardial infarction is 20 mg twice daily. The dose should be increased with a target of 160 mg daily if tolerated without side effects.
Administration
Administration of Valsartan with food decreases the absorption of Valsartan by about 40%, so it should be taken on an empty stomach. No initial dosage adjustment is required for elderly patients with mild to moderate renal and hepatic insufficiency.
Interaction
No drug interactions of clinical significance have been found. Compounds that have been studied in clinical trials include Cimetidine, Warfarin, Furosemide, Digoxin, Atenolol, Indomethacin, Hydrochlorothiazide, Amlodipine, and Glibenclamide.
As Valsartan is not metabolized to a significant extent, clinically relevant drug-drug interactions in the form of metabolic induction or inhibition of the cytochrome P450 system are not expected with Valsartan. Although valsartan is highly bound to plasma proteins, in vitro studies have not shown any interaction at this level with a range of molecules that are also highly protein-bound, such as Diclofenac, Furosemide, and Warfarin. Concomitant use of potassium-sparing diuretics (e.g., Spironolactone, Triamterene, Amiloride) potassium supplements, or salt substitutes containing potassium may lead to an increase in serum potassium. If co-medication is considered necessary, caution is advisable
Contraindications
Valsartan is contraindicated in patients who are hypersensitive to any component of this product.
Side Effects
Valsartan is generally well tolerated and side effects are rare. The most common side effects include headache, dizziness, fatigue, abdominal pain, cough, diarrhea, and nausea. Patients may also experience hyperkalemia, impotency, reduced renal function, allergic reactions, dyspnea, constipation, back pain, muscle cramps, rash, anxiety, insomnia, and vertigo. Hypotension may also occur if the patient has been taking diuretics along with Valsartan.
Pregnancy & Lactation
Pregnancy: Valsartan should not be used in pregnancy, as in 2nd and 3rd trimesters it can cause injury and even death to the fetus. When pregnancy is detected, Valsartan should be stopped as soon as possible.
Nursing Mothers: It is not known whether Valsartan is excreted in human milk. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Precautions & Warnings
Impaired Hepatic Function: As the majority of Valsartan is eliminated in the bile, care should be exercised in patients with mild to moderate hepatic impairment including biliary obstructive disorder.
Impaired Renal Function: Dosage reduction or discontinuation may be required with patients having a pre-existing renal impairment.
Heart Failure and Myocardial Infarction: Caution should be exercised when initiating therapy in patients with heart failure and post-myocardial infarction patients.
Use in Special Populations
Pediatric use: Safety and effectiveness in pediatric patients have not been established.
Geriatric use: No overall difference in the efficacy or safety of Valsartan was observed in this patient population, but greater sensitivity of some elderly persons cannot be ruled out.
Hepatic Impairment:
- Mild to moderate: Max: 80 mg once daily.
- Severe: Contraindicated.
Overdose Effects
Limited data are available related to overdosage in humans. The most likely manifestations of overdosage would be hypotension and tachycardia, bradycardia could occur from parasympathetic (vagal) stimulation. If excessive hypotension occurs, the patient should be placed in the supine position and if necessary, has to be given an intravenous infusion of normal saline.
Storage Conditions
- Store in a cool & dry place below 30°C.
- Protect from light & moisture.
- Keep out of reach of children.
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