Drug Comparison

Lithium Carbonate vs. Losartan Potassium

Compare Lithium Carbonate and Losartan Potassium: mechanism of action, indications, side effects, cost, and which may be right for you.

Drug A

Losartan Potassium

Cozaar

ARBs (Angiotensin II Receptor Blockers)

Quick Comparison

Category	Lithium Carbonate	Losartan Potassium
Drug Class	Mood Stabilizers	ARBs (Angiotensin II Receptor Blockers)
Rx Status	Rx	Rx
Generic Available	Yes	No
Typical Cost	$15-$50/month	$4–$15/month

Lithium Carbonate Overview

LITHIUM CARBONATE (brand name: Lithium Carbonate) is a Mood Stabilizers. INDICATIONS Lithium carbonate extended-release tablets are indicated in the treatment of manic episodes of Bipolar Disorder. Bipolar Disorder, Manic (DSM-IV) is equivalent to Manic Depressive illness, Manic, in the older DSM-II terminology. Lithium carbonate extended-release tablets are also…

Full Lithium Carbonate guide →

Losartan Potassium Overview

Losartan potassium (Cozaar) is an angiotensin II receptor blocker (ARB) used to treat high blood pressure, protect the kidneys in type 2 diabetes, and reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy. Unlike ACE inhibitors, losartan does not cause a dry cough and carries a significantly lower risk of angioedema. It is also the only ARB with a clinically mean...

Full Losartan Potassium guide →

How Each Drug Works

Losartan Potassium

Mechanism of Action — AT1 Receptor Blockade

Losartan is a selective, competitive antagonist of the angiotensin II type 1 (AT1) receptor. Unlike ACE inhibitors, losartan does not prevent the formation of angiotensin II — instead, it blocks angiotensin II from binding to its primary receptor.

Step-by-step mechanism:

Renin-angiotensin-aldosterone system (RAAS) activation: Renin converts angiotensinogen to angiotensin I; ACE converts angiotensin I to angiotensin II via multiple pat…

Approved Uses (Indications)

Lithium Carbonate

INDICATIONS Lithium carbonate extended-release tablets are indicated in the treatment of manic episodes of Bipolar Disorder. Bipolar Disorder, Manic (DSM-IV) is equivalent to Manic Depressive illness, Manic, in the older DSM-II terminology. Lithium carbonate extended-release tablets are also indicated as a maintenance treatment for individuals with a diagnosis of Bipolar Disorder. Maintenance therapy reduces the frequency of manic episodes and diminishes the intensity of those episodes which may occur. Typical symptoms of mania include pressure of speech, motor hyperactivity, reduced need for …

Losartan Potassium

FDA-Approved Indications:

Hypertension (adults and pediatric patients ≥6 years):

Treatment of hypertension to reduce blood pressure and lower the risk of cardiovascular events
Can be used as monotherapy or in combination with other antihypertensives
Pediatric use: approved for children ≥6 years with eGFR >30 mL/min/1.73m²

Diabetic Nephropathy (type 2 diabetes with proteinuria and hypertension):

Reduces the rate of progression of nephropathy as measured by doubling of serum creatinine or ESRD
RENAAL trial: 25% reduction in doubling of serum creatinine, 28% reduction in E…

Side Effects

Lithium Carbonate

Losartan Potassium

Serious Side Effects

Hyperkalemia — can be severe (>6 mEq/L) in patients with renal impairment, diabetes, or concurrent use of potassium-sparing agentsAcute kidney injury — especially in patients with bilateral renal artery stenosis, solitary kidney, or severe heart failureHypotension — particularly in volume-depleted patients (diuretics, low-sodium diet, dialysis); first-dose effectAngioedema — rare (<0.1%), but can occur; 3–4× less common than with ACE inhibitors; may occur in patients with prior ACE inhibitor-induced angioedemaFetal/neonatal toxicity — can cause oligohydramnios, fetal renal dysfunction, skull hypoplasia, and death (Category D in 2nd/3rd trimester)

Common Side Effects

Dizziness (4–7%)Upper respiratory infection (8%)Fatigue (3–4%)Hyperkalemia (potassium >5.5 mEq/L, especially with renal impairment or diabetes)Hypotension (especially in volume-depleted patients)Elevated serum creatinine (reversible, especially with bilateral renal artery stenosis)Back pain (2–3%)Nasal congestion (2%)

Rare Side Effects

Hepatotoxicity (rare case reports)Rhabdomyolysis (rare, especially with concurrent statin use)Anemia (rare, especially in patients with renal impairment)Thrombocytopenia (rare)

Cost Comparison

Lithium Carbonate

$15-$50/month

Generic available

Generic lithium carbonate is widely available and typically affordable, especially with insurance or discount cards. Extended-release formulations may be slightly more expensive.

Losartan Potassium

$4–$15/month

Generic losartan potassium is available at most pharmacies for $4–$15/month, and is included on most $4 generic drug programs at major pharmacy chains (Walmart, Kroger, Costco). Brand-name Cozaar is significantly more expensive (~$200–$300/month) but is rarely prescribed. Hyzaar (losartan/hydrochlorothiazide combination) is also available generically at similar low cost. GoodRx and RxGo coupons can further reduce the price at most pharmacies.

Drug Interaction: Moderate

Losartan can increase serum lithium concentrations, potentially leading to lithium toxicity. ARBs reduce renal lithium clearance by causing sodium depletion and activating compensatory sodium (and lithium) reabsorption in the proximal tubule. Lithium has a narrow therapeutic index (0.6–1.2 mEq/L), and even modest increases in serum levels can cause toxicity.

Mechanism: Losartan reduces aldosterone secretion via AT1 receptor blockade, leading to mild natriuresis. The resulting sodium depletion activates compensatory sodium reabsorption in the proximal tubule via the sodium-lithium countertransporter. Since lithium is handled similarly to sodium in the proximal tubule, its reabsorption increases proportionally, reducing renal lithium clearance and raising serum lithium levels. This mechanism is shared by all ARBs and ACE inhibitors.

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Medical Disclaimer

The information on RxGuide is intended for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician, pharmacist, or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.