Spironolactone Compounded vs Branded: A Clinical Comparison

What is the difference between compounded and branded spironolactone?

Branded spironolactone is Aldactone: 25 mg, 50 mg and 100 mg tablets from Pfizer, approved as NDA 012151 on 21 January 1960, with the current label effective November 2025 [1][5]. Generic spironolactone tablets are approved separately, for example Sun Pharma's in 1986 and Mylan's in 2001 [1]. A generic drug is approved by the FDA and must meet the requirements of that approval, including establishing therapeutic equivalence to the brand-name drug [2].

A compounded preparation is not approved by the FDA, and the FDA does not verify its safety, effectiveness or quality before it is marketed [2].

Does the FDA treat compounded and generic spironolactone the same?

No. The FDA states that compounded drugs and generic drugs are not the same [2]. The agency also says compounded drugs should be used only in patients whose medical needs cannot be met by an FDA-approved drug. It warns that unnecessary use may expose patients to serious risks, including contamination or a product with too much or too little active ingredient when compounding practices are poor [2].

Do quality standards differ by compounding setting?

They do. Drugs compounded in outsourcing facilities registered with the FDA are subject to current good manufacturing practice requirements; drugs compounded by a licensed pharmacist in a state-licensed pharmacy are not [2]. State boards of pharmacy hold primary responsibility for day-to-day oversight of state-licensed pharmacies that are not registered as outsourcing facilities, while the FDA primarily oversees and inspects registered outsourcing facilities on a risk-based schedule [2].

The FDA also notes that someone buying a compounded drug online may not know which compounder produced it, including whether that compounder meets appropriate quality standards and is appropriately licensed and regulated [2].

Is there an FDA-approved liquid version?

Yes. CaroSpir is an FDA-approved spironolactone oral suspension, approved in August 2017 [1]. The FDA gives a patient who cannot swallow a tablet or capsule and needs a liquid form as one example of a need that compounding may meet [2].

What does the acne evidence show, and which product was tested?

In SAFA, a pragmatic, double-blind randomized trial in the UK, 410 women aged 18 and older with facial acne persisting at least 6 months and judged to warrant oral antibiotics were randomized: 201 to spironolactone and 209 to placebo, with usual topical treatment continued [3]. Dosing was 50 mg daily to week 6, then 100 mg daily to week 24 [3]. At week 12, Investigator's Global Assessment success was 18.5% with spironolactone versus 5.6% with placebo (adjusted odds ratio 5.18, 95% CI 2.18 to 12.28). The Acne-Specific Quality of Life symptom subscale favoured spironolactone by 1.27 points (95% CI 0.07 to 2.46) at 12 weeks and 3.77 points (2.50 to 5.03) at 24 weeks [3]. Headache occurred in 20.4% versus 12.0%; there were no serious adverse reactions [3].

The earlier systematic review by Layton and colleagues, published in the American Journal of Clinical Dermatology in 2017, retrieved 10 randomized trials and 21 case series [4]. All trials were rated at high risk of bias and the quality of evidence was low or very low for every outcome [4]. Only one crossover trial showed a statistically significant advantage, for 200 mg daily over placebo on inflamed lesions; the remaining trials could not establish how well lower doses work [4]. Menstrual side effects were significantly more common at 200 mg, and significantly less common when a combined oral contraceptive was used [4].

These studies tested oral spironolactone against placebo or other comparators. None of them tested a compounded preparation or compared compounded with branded product [3][4].

Is acne an approved use of spironolactone?

No. Acne is an off-label use [5]. The labeled indications for Aldactone are NYHA Class III to IV heart failure with reduced ejection fraction, add-on therapy for hypertension, edema in cirrhosis or nephrotic syndrome, and primary hyperaldosteronism [5]. The label says spironolactone binds the androgen receptor, which underlies its anti-androgen effects, and it cites antiandrogenic effects in animals [5]. Gynecomastia is the most common adverse reaction on the label: about 9% of men in RALES, a heart failure trial at a mean dose of 26 mg daily [5].

What does the Aldactone label list as safety issues?

The Aldactone label describes hyperkalemia, hypotension, worsening kidney function, electrolyte changes, gynecomastia and menstrual effects [5].

Hyperkalemia is the main one. The label says spironolactone can cause hyperkalemia and that the risk rises with impaired renal function, potassium supplements, potassium-containing salt substitutes, and drugs that raise potassium such as ACE inhibitors and ARBs. It says to monitor serum potassium within 1 week of initiation or dose titration and regularly thereafter, and to decrease the dose or discontinue and treat if hyperkalemia occurs [5]. Spironolactone is contraindicated in hyperkalemia, in Addison's disease, and with concomitant eplerenone [5]. The label says spironolactone reduces lithium clearance and raises the risk of lithium toxicity, and says to monitor lithium levels periodically [5]. It also says NSAIDs can reduce the diuretic, natriuretic and antihypertensive effect [5].

Pregnancy: because of its anti-androgenic properties and rat data showing feminization of male fetuses, the label says to avoid spironolactone in pregnant women or to advise a pregnant woman of the potential risk to a male fetus. It adds that limited human case reports did not show an association with major malformations [5]. Irregular menses and amenorrhea appear among the adverse reactions reported for spironolactone [5]. In a retrospective case series of 403 women treated for acne, menstrual adverse effects were less common among those using combined oral contraception (odds ratio 0.23, 95% CI 0.11 to 0.50) [7].

In one retrospective study of 974 healthy young women taking spironolactone for acne, 13 of 1802 potassium measurements were abnormal (0.72%), against a baseline rate of 0.76% in 1165 comparison women, and 6 of the 13 repeated normal [8]. That study excluded women with heart or kidney disease and those taking drugs that act on the renin-angiotensin system. Its authors concluded routine monitoring had low usefulness in that group [8]. The Aldactone label still says to monitor potassium [5].

Why do spironolactone labels differ on the boxed warning?

The current Aldactone label has no boxed warning [5]. Some older-format generic and repackager labels still carry a boxed warning stating that spironolactone has been shown to be a tumorigen in chronic toxicity studies in rats [6].