Valsartan
Valsartan (Diovan) is an angiotensin II receptor blocker (ARB) that treats hypertension, heart failure, and provides cardioprotection after myocardial infarction. It works by selectively blocking AT1 receptors, preventing angiotensin II from causing vasoconstriction and aldosterone release. Unlike ACE inhibitors, it does not inhibit bradykinin breakdown, so it does not cause the persistent dry cough seen in 10–15% of ACE inhibitor users. Key risks include hyperkalemia, hypotension, and — critically — fetal toxicity (pregnancy category X in the 2nd and 3rd trimesters). The 2018 NDMA contamination recall affected certain generic manufacturers.
Uses & FDA Indications
Valsartan was approved by the FDA in 1996 and is among the most frequently prescribed ARBs worldwide. It belongs to the drug class that replaced ACE inhibitors in patients who cannot tolerate the characteristic ACE inhibitor cough — a direct consequence of its different mechanism of action.
FDA-approved indications include: hypertension (high blood pressure) in adults and children 6 years and older; heart failure (NYHA Class II–IV) to reduce hospitalization; and reduction of cardiovascular mortality in clinically stable patients with left ventricular failure or left ventricular dysfunction following myocardial infarction.
Valsartan is also a component of sacubitril/valsartan (Entresto), a combination drug approved for heart failure with reduced ejection fraction (HFrEF) that combines an ARB with a neprilysin inhibitor — a newer drug class with mortality benefit in heart failure trials.
How It Works
Valsartan selectively blocks the angiotensin II type 1 (AT1) receptor. Angiotensin II is a potent vasoconstrictor and pro-inflammatory hormone produced through the renin-angiotensin-aldosterone system (RAAS). When AT1 receptors are blocked, the downstream effects of angiotensin II — vasoconstriction, aldosterone release, sodium retention, and sympathetic nervous system activation — are all reduced, leading to lower blood pressure, reduced cardiac afterload, and decreased sodium and water retention.
The key distinction from ACE inhibitors is that ARBs block the receptor rather than the enzyme that produces angiotensin II. ACE inhibitors also prevent the breakdown of bradykinin (a vasodilatory peptide); accumulated bradykinin is responsible for the dry cough and, more rarely, angioedema associated with ACE inhibitors. Because valsartan does not affect the ACE enzyme, bradykinin levels remain normal and cough is not a class effect.
Valsartan and sacubitril are combined in Entresto (sacubitril/valsartan), which has demonstrated superior mortality reduction compared to enalapril alone in the PARADIGM-HF trial for heart failure with reduced ejection fraction. The combination represents a distinct therapeutic advance over standalone ARBs in this population.
2018 NDMA CONTAMINATION RECALL: The FDA recalled numerous valsartan products from specific manufacturers due to NDMA (N-nitrosodimethylamine) contamination — a probable human carcinogen formed as a manufacturing byproduct. Patients on recalled lots were advised not to abruptly stop their medication but to contact their prescriber for a switch to an unaffected product. The recall did not affect all valsartan manufacturers.
Side Effects
Common
- Hyperkalemia (elevated potassium) — due to reduced aldosterone; requires monitoring, particularly in CKD and with concurrent potassium-raising medications
- Hypotension — especially with first dose, volume depletion, or diuretic co-administration; dizziness upon standing (orthostatic hypotension)
- Dizziness, fatigue — common during initiation and dose titration
- Headache
- Elevated serum creatinine — transient, mild increases are expected; significant rises may indicate bilateral renal artery stenosis
Serious
- Fetal toxicity — use during the 2nd and 3rd trimesters causes fetal renal dysgenesis, oligohydramnios, and neonatal death. Contraindicated in pregnancy.
- Angioedema — less common than with ACE inhibitors, but cases have been reported; can be life-threatening if it involves the airway
- Acute kidney injury — in patients with bilateral renal artery stenosis or severe volume depletion; ARBs depend on efferent arteriolar tone to maintain GFR
- Significant hyperkalemia — particularly dangerous in patients with advanced renal impairment or concurrent use of potassium-sparing agents
Drug Interactions
| Drug / Class | Interaction | Clinical Significance |
|---|---|---|
| ACE Inhibitors (lisinopril, enalapril, ramipril) | Dual RAAS blockade substantially increases hyperkalemia, hypotension, and acute kidney injury risk without clear additional cardiovascular benefit for most patients. | High — avoid combination; generally contraindicated |
| Potassium-Sparing Diuretics (spironolactone, eplerenone, amiloride) | Additive hyperkalemia risk; both reduce potassium excretion. Can cause dangerous hyperkalemia, especially in CKD. | High — use with caution; close potassium monitoring required |
| NSAIDs (ibuprofen, naproxen, celecoxib) | NSAIDs blunt the antihypertensive effect of valsartan and may precipitate acute kidney injury, particularly in volume-depleted patients. | Moderate-High — avoid chronic NSAID use; monitor BP and renal function |
| Lithium | ARBs reduce lithium clearance by the kidneys, raising plasma lithium levels into the toxic range. Risk of lithium toxicity. | High — monitor lithium levels closely if used together |
| Aliskiren (direct renin inhibitor) | Combined RAAS blockade with aliskiren is contraindicated in patients with diabetes or CKD due to renal impairment and hyperkalemia risk. | High — contraindicated in diabetes/CKD; generally avoid |
Warnings & Contraindications
Contraindications
- Pregnancy (2nd and 3rd trimesters) — fetal toxicity; use any trimester carries risk
- Hypersensitivity to valsartan
- Concomitant use with aliskiren in patients with diabetes
- Concomitant use with sacubitril/valsartan (Entresto) — cannot double up on the valsartan component
Pregnancy Warning (Boxed)
Valsartan carries a boxed warning for fetal toxicity. When used during the second and third trimesters of pregnancy, drugs that act on the RAAS can cause fetal renal dysfunction, oligohydramnios, skeletal malformations, and neonatal death. Women of childbearing potential should be counseled to use effective contraception and to stop the drug immediately upon confirmed pregnancy.
Renal Artery Stenosis
In patients with bilateral renal artery stenosis or stenosis in a single functioning kidney, ARBs can cause a marked reduction in GFR and acute kidney injury. The glomerular filtration in these patients is maintained by angiotensin II-mediated efferent arteriolar constriction — blocking this response with an ARB causes GFR to drop precipitously. Use with extreme caution, if at all, in this setting.
Check for hyperkalemia risk, RAAS interaction conflicts, or other valsartan interactions.
Check Drug Interactions →Frequently Asked Questions
What is the difference between valsartan and lisinopril?
Both valsartan (an ARB) and lisinopril (an ACE inhibitor) lower blood pressure by blocking the renin-angiotensin-aldosterone system (RAAS), but they act at different points. Lisinopril blocks ACE, the enzyme that converts angiotensin I to angiotensin II, but this also prevents the breakdown of bradykinin, causing a dry cough in roughly 10–15% of patients. Valsartan directly blocks the AT1 angiotensin receptor without affecting bradykinin, so it does not cause cough. Patients who cannot tolerate ACE inhibitor cough are frequently switched to an ARB like valsartan. Both drug classes are generally considered equivalent for blood pressure control, though certain clinical situations may favor one over the other.
What was the 2018 valsartan recall about?
In 2018, the FDA announced a major recall of valsartan products manufactured by certain overseas suppliers (primarily Zhejiang Huahai Pharmaceutical) after testing revealed contamination with NDMA (N-nitrosodimethylamine), a probable human carcinogen. NDMA is a nitrosamine compound that forms as a byproduct of certain manufacturing processes. The contamination affected a significant portion of the US valsartan supply. The FDA conducted a thorough review and the affected batches were recalled. Not all valsartan products were affected; many manufacturers producing clean product continued distribution. Patients were advised not to stop their medication abruptly but to contact their prescriber to switch to a clean alternative.
Can valsartan cause high potassium?
Yes. Valsartan and all ARBs can raise serum potassium (hyperkalemia) because blocking the AT1 receptor reduces aldosterone secretion, which normally promotes potassium excretion in the kidneys. The risk is particularly elevated in patients with chronic kidney disease, diabetes, or those taking other potassium-raising drugs such as ACE inhibitors, potassium-sparing diuretics (spironolactone, eplerenone), or potassium supplements. Combining valsartan with an ACE inhibitor is generally not recommended due to compounding hyperkalemia and hypotension risks. Periodic potassium monitoring is appropriate, especially at initiation and after dose changes.