Hidden Prescription Drugs in “Natural” Supplements

A capsule sold as an herbal blend can hold a full prescription dose of a drug that appears nowhere on its label. Between 2007 and 2016 the U.S. Food and Drug Administration warned the public about 776 such products, and 98 percent of them fell into just three categories: sexual enhancement, weight loss and muscle building. This page explains how a product like that reaches a shelf in the first place, which drugs turn up and why, why an unlabelled dose is more dangerous than the same drug from a pharmacy, how to check a product against the FDA’s own records, and what to do if you have already taken one.

Table of Contents

  1. Why a Supplement Reaches the Shelf Untested
  2. The Three Categories That Dominate FDA Warnings
  3. Sexual Enhancement: Sildenafil, Tadalafil and Their Analogues
  4. The “Rhino” Family: A Documented Example
  5. Why an Uncontrolled PDE5 Dose Is Dangerous: Nitrates and Blood Pressure
  6. Weight Loss: Sibutramine, Phenolphthalein and Fluoxetine
  7. Muscle Building: Anabolic Steroids Sold as Supplements
  8. Recalled, but Still on Sale
  9. How to Check a Product Against the FDA’s Records
  10. Red Flags on the Label and on the Shelf
  11. If You Have Taken One and Feel Unwell
  12. The Honest Bottom Line
  13. Research Papers
  14. Connections
  15. Featured Videos

1. Why a Supplement Reaches the Shelf Untested

The Dietary Supplement Health and Education Act of 1994 (DSHEA) placed vitamins, minerals, herbs, amino acids and similar ingredients in a legal category of their own, closer to food than to medicine. The practical consequence is stated plainly on the FDA’s own consumer page: the agency “does not have the authority to approve dietary supplements before they are marketed,” and a firm “does not have to provide FDA with the evidence it relies on to substantiate safety before or after it markets its products,” apart from a narrow rule for genuinely new ingredients. The FDA’s tools are all after-the-fact: inspections, watching the marketplace, examining imports, and investigating reports of harm.

Think of two doors into the same building. A prescription drug has to show its papers — trials, manufacturing records, a label the FDA has read — before it is allowed in. A supplement walks in unasked and is only questioned if someone later complains. Until December 22, 2007, not even a complaint had to reach the agency; a law signed on December 22, 2006 (Public Law 109-462) first required the firm named on a supplement label to forward reports of serious adverse events to the FDA.

It matters to be precise about what is legal here. A capsule that contains sildenafil or an anabolic steroid is not a lawful supplement with a problem — in law it is an unapproved drug, and selling it is illegal. The difficulty is that nothing in the system detects it before sale. In the California Department of Public Health analysis of FDA warnings discussed below, 38.6 percent of the adulterated products found in 2014–2016 were identified because the FDA bought them online and tested them, and another 34.3 percent because inspectors opened international mail. The products were caught by sampling, not by disclosure. A 2015 review in the American Journal of Public Health summarised the result of this design as regulation that arrives “too little, too late.”

2. The Three Categories That Dominate FDA Warnings

The clearest picture comes from a 2018 study in JAMA Network Open by Tucker and colleagues, who went through every FDA warning about an adulterated supplement from 2007 through 2016. They found 776 products from 146 companies. Three uses accounted for almost all of them:

One product in five (157, or 20.2 percent) contained more than one hidden drug. Twenty-eight products were named in two or three separate warnings more than six months apart, and 19 of those had a new unapproved ingredient by the later warning — the same name back on sale with a different drug inside. A fourth, smaller pattern — joint-pain products such as Reumofan Plus and Artri King that were found to contain a hidden corticosteroid, an NSAID and a muscle relaxant — has its own page: Hidden Steroids and NSAIDs in Joint-Pain Products.

For scale, a 2015 study in the New England Journal of Medicine estimated that adverse events from dietary supplements of all kinds bring about 23,005 people a year to U.S. emergency departments, with about 2,154 of them admitted. Not all of those visits involve hidden drugs, but the category overlap is telling: weight-loss and energy products accounted for 71.8 percent of the supplement-related visits for palpitations, chest pain or a racing heart.

3. Sexual Enhancement: Sildenafil, Tadalafil and Their Analogues

Sildenafil (Viagra) and tadalafil (Cialis) belong to a drug class called PDE5 inhibitors. They are effective, they are cheap to buy in bulk, and they produce an effect a customer can feel within an hour — which is exactly the effect a “natural” product cannot honestly deliver. So the drug goes into the capsule and the label talks about horny goat weed.

The most direct evidence of how common this is comes from a 2013 study in the Journal of Sexual Medicine. Investigators bought 91 samples of 58 different “herbal” or “all natural” sexual-performance products, nearly all from convenience stores and filling stations in two U.S. cities, priced from $2.99 to $17.99. None declared a synthetic ingredient. Seventy-four of the 91 (81 percent) contained a PDE5 inhibitor: 40 held tadalafil and/or sildenafil, and 18 of those held more than 110 percent of the highest approved prescription strength. The other 34 held analogues — chemical cousins of the approved drugs. Contents varied widely between samples of the same product, which the authors read as a sign of minimal quality control; 23 samples lacked a lot number or expiry date; and only 14 of the 91 carried any warning about nitrates.

The analogues deserve their own sentence. A 2012 review from the Dutch National Institute for Public Health counted at least 46 different sildenafil, tadalafil and vardenafil analogues already reported in food supplements, most of them lifted from the pharmaceutical patent literature, where they had already been described. The authors call them “experimental drugs in essence because most have no known efficacy or safety profile.” An analogue has an obvious attraction for a manufacturer — a routine test for sildenafil may not detect it — and the buyer becomes the first person to test it.

Occasionally the hidden ingredient is not even in the same class. In May 2023 the FDA reported that Rhino 7S Type F3 7000 contained both sildenafil and acetaminophen — a pain reliever that is harmless at the labelled dose and damaging to the liver in overdose, and that is already in many other products a person might be taking. See Acetaminophen Overdose.

4. The “Rhino” Family: A Documented Example

The FDA rarely names a whole product family, but it did so on November 27, 2018, in a press statement warning consumers not to buy or use products sold under the name “Rhino.” The record says: since 2007 the agency had identified “more than 25 products marketed with variations of the name ‘Rhino’ that contained hidden drug ingredient(s),” the ingredients being sildenafil and/or tadalafil; the products “continue to be sold at gas stations and convenience stores, as well as on websites such as eBay and Amazon”; and the agency had “received reports of people experiencing chest pain, severe headaches and prolonged erections after taking a Rhino product that led to surgical intervention and hospitalization due to extreme drops in blood pressure.” The statement also disclosed a criminal investigation, open since 2015, into the smuggling of raw materials and the manufacture and distribution of Rhino capsules in the Los Angeles area, a case being prosecuted by the Department of Justice. (The fda.gov page has since been taken down; an archived copy is linked under Regulatory Records below.)

The individual FDA laboratory notices show how the family mutates while the drug stays the same:

Eight years, capsules to gummies to chocolate, the same two drugs. Every one of those notices carries the FDA’s standard sentence: the undeclared ingredient “may interact with nitrates found in some prescription drugs, such as nitroglycerin, and may lower blood pressure to dangerous levels,” and “people with diabetes, high blood pressure, high cholesterol, or heart disease often take nitrates.” That sentence is the subject of the next section, because it is the reason this category is more than embarrassing.

5. Why an Uncontrolled PDE5 Dose Is Dangerous: Nitrates and Blood Pressure

Blood vessels relax when a messenger molecule called cGMP builds up inside their muscle wall. Nitric oxide makes cGMP; an enzyme called PDE5 breaks it down. Nitrate heart medicines — nitroglycerin tablets and sprays for chest pain, and isosorbide mononitrate or dinitrate taken daily — work by supplying nitric oxide. Sildenafil and tadalafil work by blocking PDE5. One fills the bath; the other blocks the drain. Taken together they do not add — they multiply, and the pressure in the arteries can fall far enough to cause fainting, a heart attack from an underfilled heart, or worse.

This was measured before Viagra was a year old. In a 1999 crossover study in the American Journal of Cardiology, healthy men took sildenafil 25 mg or placebo and were then given nitroglycerin. On sildenafil they were significantly less able to tolerate an intravenous nitroglycerin infusion (judged by a fall of more than 25 mm Hg or symptomatic low blood pressure), and a single 500-microgram tablet under the tongue produced a fall in systolic pressure four times larger than on placebo. The authors’ conclusion is the one that appears in every label since: sildenafil in anyone using organic nitrates, “either regularly and/or intermittently, in any form is contraindicated.” The same study found that with the ordinary blood-pressure drug amlodipine the effect was additive rather than multiplied — a further 8/7 mm Hg — which is why the nitrate interaction is treated as a different order of problem.

The FDA-approved prescribing information adds the time dimension. The Viagra label states that nitrates in any form are contraindicated and that, after a dose, “it is unknown when nitrates, if necessary, can be safely administered” — sildenafil levels are much lower at 24 hours, but safety at that point has not been shown. The Cialis label is stricter because tadalafil lasts longer: where a nitrate is medically necessary in a life-threatening situation, “at least 48 hours should elapse after the last dose.”

Now put the pieces together for the man most likely to buy a product at a filling station. Erectile difficulty and coronary artery disease share a cause — narrowed, stiffened arteries — so the customers for these products overlap heavily with the men who carry nitroglycerin in a pocket or take isosorbide every morning. With a prescription, a doctor checks that list before writing it. With a “herbal” capsule nobody checks, the dose is unknown (18 of the 91 samples in the 2013 study exceeded the highest approved strength), and if the ingredient is an analogue there is no safety data at all. There is a second trap in the emergency room: chest pain is treated first with nitroglycerin. A man who took a hidden-tadalafil gummy on Friday and arrives with chest pain on Saturday is at risk from the treatment itself unless he says what he took — which is why the advice in Section 11 is so specific.

6. Weight Loss: Sibutramine, Phenolphthalein and Fluoxetine

Sibutramine was the prescription appetite suppressant Meridia, approved in 1997. In the SCOUT trial, published in the New England Journal of Medicine in 2010, 9,804 overweight or obese people aged 55 or over with heart disease, type 2 diabetes or both were randomised to sibutramine or placebo for an average of 3.4 years. Sibutramine produced only a small extra weight loss (a mean of 1.7 kg after the run-in) and raised the rate of the main outcome — heart attack, stroke, resuscitated cardiac arrest or cardiovascular death — from 10.0 percent to 11.4 percent, a 16 percent relative increase. Non-fatal heart attack rose from 3.2 to 4.1 percent and non-fatal stroke from 1.9 to 2.6 percent. Deaths were not increased. Abbott withdrew the drug and the FDA formally withdrew its approval on December 21, 2010.

Withdrawal ended the legal supply but not the demand, and that is why sibutramine keeps appearing in “herbal” slimming products: it works a little, it is cheap as a bulk chemical, and no pharmacy can compete for the customer. In the FDA warning data it was the hidden drug in 84.9 percent of adulterated weight-loss products. A 2016 French laboratory study analysed 160 weight-loss supplements, mainly bought online, every one of which claimed to be 100 percent natural; 56 percent were tainted. Forty-three contained sibutramine alone, nine phenolphthalein alone and 23 both, with sibutramine ranging from 0.1 to 22 mg per dose and varying between blisters from the same box. A German forensic case report from 2006 measured 27.4 mg of sibutramine in a single capsule of a “Chinese herbal” slimming product ordered online — about twice the highest single dose ever authorised in Germany, where the case was analysed — in a healthy young woman whose severe headache, dizziness and numbness stopped when she stopped the capsules. The FDA notes that some of these products direct customers to take more than three times the recommended dose, enough to cause raised blood pressure, a racing heart, palpitations and seizures even in a healthy person.

Phenolphthalein is an old laxative. In 1999 the FDA reclassified it as “not generally recognized as safe and effective” for over-the-counter use because research showed a potential cancer risk and it was found to be genotoxic — able to damage DNA. It turns up in slimming products for the crude reason that a laxative produces a visible “result”; in the 2016 study it was measured at up to 56 mg per dose.

Fluoxetine is the antidepressant Prozac. It has been found in weight-loss products, presumably because it can blunt appetite. The FDA points out that it carries a boxed warning for increased suicidal thinking in children, adolescents and young adults. For anyone already taking an antidepressant, an undeclared second serotonergic drug is a risk of its own. The stimulants that make up the rest of the weight-loss and energy category are covered on Stimulants in Weight-Loss and Energy Products.

7. Muscle Building: Anabolic Steroids Sold as Supplements

In the FDA warning data, 89.1 percent of adulterated muscle-building products contained synthetic steroids or steroid-like compounds. The sports-doping laboratories saw this first. A Cologne group reported in 2008 that in an international survey of 634 supplements bought in 13 countries in 2001–2002, about 15 percent of ordinary non-hormonal products were contaminated with anabolic-androgenic steroids, mainly prohormones, apparently by cross-contamination during manufacture. From 2002 they began finding products deliberately faked with classic anabolic steroids — metandienone, stanozolol, boldenone, oxandrolone — none declared on the label, and in 2005 even vitamin C, multivitamin and magnesium tablets were confiscated with stanozolol and metandienone in them. “Designer” steroids such as methasterone followed.

A 2015 review in Andrology describes how these compounds are marketed — as “pro-hormones,” “natural steroids,” “testosterone boosters” — and what they do: liver toxicity and cholestasis, kidney failure, shut-down of the body’s own testosterone (hypogonadism), breast enlargement in men, and infertility. The authors suggest that anabolic steroid use may be the most common cause of hypogonadism in men of reproductive age, and that earlier studies undercounted it because they did not account for designer-steroid use.

The FDA’s own review, published in June 2017, found 35 cases of serious liver injury — hospitalisation or life-threatening — between July 2009 and December 2016 in men aged 20 to 48 who had used body-building products labelled or suspected to contain steroids or “steroid alternatives.” Its current consumer advisory adds heart attack, stroke, pulmonary embolism and kidney damage to the list, notes that the products are typically “promoted as hormone products and/or as alternatives to anabolic steroids,” and tells anyone using one to consult a health professional promptly. Liver injury from supplements of every kind is covered on Liver Injury from Supplements.

8. Recalled, but Still on Sale

It is natural to assume that once the FDA recalls a product, the problem is over. A 2014 research letter in JAMA tested that assumption. Cohen and colleagues took the 274 supplements the FDA had recalled for hidden drugs between 2009 and 2012, found 27 that were still being sold from the manufacturers’ or retailers’ own websites in mid-2013, and bought them — on average 34 months after the recall. Eighteen of the 27 (66.7 percent) still contained at least one banned drug: 11 of 13 sports products (85 percent), 6 of 9 weight-loss products (67 percent), and 1 of 5 sexual-enhancement products. Six of the 27 (22.2 percent) contained an additional banned drug the FDA had not named in the recall. Products made in the United States fared no better: 13 of 20 remained adulterated.

Together with the 28 repeat offenders in the warning data, this gives a rule worth remembering: a recall is a snapshot, not a clean-up. A product name that has appeared once in the FDA’s records should be treated as suspect whenever it reappears, whatever the label now says.

9. How to Check a Product Against the FDA’s Records

For years the FDA published a list called “Tainted Products Marketed as Dietary Supplements” under its Center for Drug Evaluation and Research — the database the 2018 study was built from. That page no longer exists at its old address; its contents now live in the FDA’s Health Fraud Product Database, a single searchable table. Each row gives the date, product name, firm and its address, where the product was sold, the subject of the violation (for example an undeclared drug), the FDA action taken (public notification, recall, warning letter) and any further outcome. A box at the top filters the table as you type. At the time of writing it holds entries from December 2022 onward; earlier notices are kept in category lists under Medication Health Fraud Notifications, including one for sexual enhancement and energy products and one for weight-loss products.

  1. Type the product name, then try it without the number and with obvious spelling variants. Families like Rhino carry dozens of suffixes.
  2. Type the firm name from the label, if there is one. A firm that has been warned once has usually been warned more than once.
  3. Type an ingredient — sildenafil, tadalafil, sibutramine, phenolphthalein, fluoxetine — to see what the pattern looks like in your product’s category. Ten minutes of this teaches more than any label.
  4. Read the Subject and Action columns. “Contains hidden drug ingredient” is the phrase this page is about.
  5. Do not read absence as safety. The FDA finds these products by buying and testing a sample of what is on sale; most products in these categories have never been tested by anyone.

The FDA’s companion page, Avoiding Products Contaminated with Hidden Ingredients, distils its advice to a few lines: be wary of claims that seem too good to be true and of listings with piles of rave reviews; be especially wary of anything sold for sexual enhancement, energy, weight loss, pain, bodybuilding or sleep; and remember that “FDA does not approve facilities,” so “FDA-approved” on a supplement is a warning sign in itself. Third-party testing programmes that can vouch for what is actually in a bottle are explained on How to Verify a Supplement Before You Take It.

10. Red Flags on the Label and on the Shelf

Because names change and the drugs do not, the useful skill is recognising the pattern. A single rule covers most of it: if it works like the drug, assume it is the drug. No herb produces the effect of 100 mg of sildenafil in 30 minutes, or a week’s weight loss in a week, or muscle without training. The specific tells:

11. If You Have Taken One and Feel Unwell

  1. Stop taking it and keep the package, including any remaining capsules. A laboratory can test them; the ER can read them.
  2. Call Poison Control at 1-800-222-1222 (free, confidential, 24 hours a day, from anywhere in the United States) for advice, even if your symptoms seem mild. They will tell you whether you need to be seen.
  3. Call 911 or go to an emergency department for chest pain, fainting or near-fainting, a severe headache or any change in vision, a racing or pounding heart, a seizure, an erection lasting more than 4 hours, or yellowing of the eyes or skin and dark urine.
  4. Tell them exactly what you took and show the package. This is the single most important step. If the product contained a PDE5 inhibitor, nitroglycerin — the routine first treatment for chest pain — can be dangerous for at least 24 to 48 hours, and the team needs to know that before they treat you. Hidden sibutramine explains a fast heart and high blood pressure; hidden steroids explain abnormal liver tests. “An herbal supplement” tells a doctor nothing; the product name, looked up in the FDA database, may tell them everything.
  5. Tell your pharmacist, who can check the drug you were unknowingly taking against everything you are prescribed.
  6. Report it to the FDA through MedWatch. Reports from the public and from clinicians are part of how the agency learns which products are causing harm.

12. The Honest Bottom Line

The hidden-drug problem is real, but it is concentrated and predictable. Nearly every FDA warning falls into three categories — sexual enhancement, weight loss and muscle building — and within them the drugs are the same few, year after year: sildenafil and tadalafil and their untested analogues, sibutramine and phenolphthalein, anabolic steroids. In those three categories a “natural” product bought outside a pharmacy should be treated as unlabelled medication of unknown dose, and the honest advice is not to take it. If you want the effect of the drug, get the drug from a prescriber, where the dose is known, the interactions are checked and the nitrate question is asked. Recalls do not clear shelves, so check the database before you buy, and again before you re-buy.

Outside those categories, hidden prescription drugs are uncommon. Most vitamins, minerals and herbs sold for ordinary purposes carry different risks — overdose, liver injury, contamination, substitution — and those have their own pages in this section. The skill this page teaches is the same one that protects against all of them: read what the product promises, ask what could deliver that promise, and check the record.

Back to Table of Contents

Research Papers

  1. Tucker J, Fischer T, Upjohn L, Mazzera D, Kumar M. Unapproved Pharmaceutical Ingredients Included in Dietary Supplements Associated With US Food and Drug Administration Warnings. JAMA Netw Open. 2018;1(6):e183337. doi:10.1001/jamanetworkopen.2018.3337 — 776 adulterated products in FDA warnings 2007–2016; 45.5% sexual enhancement (sildenafil), 40.9% weight loss (sibutramine), 11.9% muscle building (steroids); 20.2% held more than one drug.
  2. Cohen PA, Maller G, DeSouza R, Neal-Kababick J. Presence of Banned Drugs in Dietary Supplements Following FDA Recalls. JAMA. 2014;312(16):1691-1693. doi:10.1001/jama.2014.10308 — 18 of 27 recalled supplements bought a mean of 34 months after recall still contained a banned drug; 6 contained a banned drug not named in the recall.
  3. Geller AI, Shehab N, Weidle NJ, et al. Emergency Department Visits for Adverse Events Related to Dietary Supplements. N Engl J Med. 2015;373(16):1531-1540. doi:10.1056/NEJMsa1504267 — an estimated 23,005 emergency visits and 2,154 admissions a year; weight-loss and energy products behind 71.8% of visits for palpitations, chest pain or tachycardia.
  4. James WPT, Caterson ID, Coutinho W, et al.; SCOUT Investigators. Effect of Sibutramine on Cardiovascular Outcomes in Overweight and Obese Subjects. N Engl J Med. 2010;363(10):905-917. doi:10.1056/NEJMoa1003114 — the trial behind the 2010 withdrawal: primary cardiovascular events 11.4% vs 10.0% (hazard ratio 1.16); non-fatal heart attack and stroke increased; deaths not increased.
  5. Venhuis BJ, de Kaste D. Towards a decade of detecting new analogues of sildenafil, tadalafil and vardenafil in food supplements: a history, analytical aspects and health risks. J Pharm Biomed Anal. 2012;69:196-208. doi:10.1016/j.jpba.2012.02.014 — at least 46 PDE5-inhibitor analogues reported in supplements, most taken from patent literature; “experimental drugs in essence.”
  6. Campbell N, Clark JP, Stecher VJ, et al. Adulteration of purported herbal and natural sexual performance enhancement dietary supplements with synthetic phosphodiesterase type 5 inhibitors. J Sex Med. 2013;10(7):1842-1849. doi:10.1111/jsm.12172 — 74 of 91 convenience-store samples (81%) contained a PDE5 inhibitor; 18 exceeded the highest approved strength; only 14 warned about nitrates.
  7. Webb DJ, Freestone S, Allen MJ, Muirhead GJ. Sildenafil citrate and blood-pressure-lowering drugs: results of drug interaction studies with an organic nitrate and a calcium antagonist. Am J Cardiol. 1999;83(5A):21C-28C. doi:10.1016/S0002-9149(99)00044-2 — sildenafil made men markedly less tolerant of nitroglycerin, with a four-fold larger fall in systolic pressure after a sublingual tablet; nitrates in any form contraindicated.
  8. Jung J, Hermanns-Clausen M, Weinmann W. Anorectic sibutramine detected in a Chinese herbal drug for weight loss. Forensic Sci Int. 2006;161(2-3):221-222. doi:10.1016/j.forsciint.2006.02.052 — 27.4 mg of sibutramine per capsule in a “herbal” slimming product ordered online, about twice the highest authorised single dose.
  9. Hachem R, Assemat G, Martins N, et al. Proton NMR for detection, identification and quantification of adulterants in 160 herbal food supplements marketed for weight loss. J Pharm Biomed Anal. 2016;124:34-47. doi:10.1016/j.jpba.2016.02.022 — 56% of 160 “100% natural” slimming products were tainted, mostly with sibutramine and/or phenolphthalein; sildenafil in 12, fluoxetine in 4; contents varied between blisters of the same box.
  10. Geyer H, Parr MK, Koehler K, Mareck U, Schänzer W, Thevis M. Nutritional supplements cross-contaminated and faked with doping substances. J Mass Spectrom. 2008;43(7):892-902. doi:10.1002/jms.1452 — about 15% of 634 supplements from 13 countries contained undeclared anabolic steroids; later products deliberately faked with metandienone, stanozolol and other classic steroids.
  11. Rahnema CD, Crosnoe LE, Kim ED. Designer steroids — over-the-counter supplements and their androgenic component: review of an increasing problem. Andrology. 2015;3(2):150-155. doi:10.1111/andr.307 — “pro-hormone” and “testosterone booster” products containing anabolic steroids; liver toxicity, kidney failure, hypogonadism, gynecomastia and infertility reported.
  12. Starr RR. Too Little, Too Late: Ineffective Regulation of Dietary Supplements in the United States. Am J Public Health. 2015;105(3):478-485. doi:10.2105/AJPH.2014.302348 — a review of the post-market regulatory design under DSHEA and the enforcement gaps it leaves.

Regulatory Records

  1. FDA. Questions and Answers on Dietary Supplements — the agency “does not have the authority to approve dietary supplements before they are marketed.” fda.gov
  2. FDA. OTC Products and Dietary Supplements (reporting serious problems) — Public Law 109-462 signed December 22, 2006, requirements effective December 22, 2007. fda.gov
  3. FDA. Health Fraud Product Database (the successor to the CDER “Tainted Products Marketed as Dietary Supplements” list) fda.gov; Medication Health Fraud Notifications by category fda.gov; Avoiding Products Contaminated with Hidden Ingredients (current as of June 10, 2025) fda.gov
  4. FDA press statement, November 27, 2018: FDA warns consumers to avoid Rhino male enhancement products found at retailers because of undeclared and potentially dangerous drug ingredients. The fda.gov page has since been removed; archived copy: web.archive.org
  5. FDA public notifications: Rhino 69 Extreme 50000 (March 28, 2018, tadalafil); Black Rhino 25000 (July 31, 2018, sildenafil); Rhino 7S Type F3 7000 (May 5, 2023, sildenafil and acetaminophen); Rhino 69 Gummy (December 26, 2024, tadalafil); Rhino Choco VIP Chocolate for Men (February 11, 2026, tadalafil).
  6. FDA. Questions and Answers about FDA’s Initiative Against Contaminated Weight Loss Products — sibutramine approved 1997 and withdrawn December 2010; phenolphthalein reclassified in 1999 as not generally recognised as safe and effective; fluoxetine’s boxed warning. fda.gov
  7. Federal Register, December 21, 2010: Abbott Laboratories, Inc.; Withdrawal of Approval of a New Drug Application for Meridia (sibutramine hydrochloride). govinfo.gov
  8. FDA, June 20, 2017: FDA analysis shows body-building products labeled to contain steroid and steroid-like substances continue to inflict serious liver injury (35 cases, July 2009–December 2016). fda.gov; Consumer Update: Caution: Bodybuilding Products Can Be Risky. fda.gov
  9. FDA-approved prescribing information (via DailyMed, U.S. National Library of Medicine): VIAGRA (sildenafil) — nitrates in any form contraindicated; CIALIS (tadalafil) — at least 48 hours before a nitrate is considered.
  10. Poison Control, 1-800-222-1222. poison.org; FDA MedWatch adverse-event reporting. fda.gov

Back to Table of Contents

Connections

Back to Table of Contents