Bay Area Medical Information
Over-the-Counter Medicine
for Weight Loss
In general...

Many weight-loss products claim to be natural or herbal, but that doesn't mean they're safe. In fact, they may harm you if you take other medications, and they could be extremely dangerous if you have certain medical conditions. People tend to consider OTC drugs and herbs to be safer than prescription drugs, yet this is simply not true. It's a good idea to check with your doctor before using any herbal or natural weight-loss product.(12)

Ally (orlistat): Fat-blocking weight-loss pill, , which has been available by prescription, is now sold in a reduced-strength version over the counter February 2007
Xenical, the prescription version of orlistat, was initially approved in 1999 as a prescription drug to treat obesity, and remains a prescription drug for obesity at twice the dose of the OTC version.

Orlistat helps produce weight loss by decreasing the intestinal absorption of fat. In controlled studies, for every five pounds people lost through diet and exercise, those using orlistat lost an additional two to three pounds. When taken with meals, orlistat blocks the absorption of about one-quarter of any fat consumed, and then results in the fat being passed out of the body in stools. About half of patients in clinical trials experienced gastrointestinal side effects such as loose stools or oily spotting. Eating a low-fat diet reduced the incidence of these adverse effects.

The 60 mg capsule can be taken up to three times a day with each fat-containing meal. Because of the possible loss of certain nutrients, the FDA recommends that people using orlistat should also take a multivitamin at bedtime.

The new OTC diet drug is approved for people 18 and older to be used along with a reduced-calorie, low-fat diet and exercise regimen. It is not for or for those who are not overweight, i.e. those who do not meet the National Institutes of Health definition of overweight, which is a body mass index of 27 or more.

Orlistat has significant side effects. Fat that isn't absorbed passes through the digestive system, causing abdominal pain, loose stools, oily flatulence, and even mild incontinence in some patients, depending on how well users comply with a low-fat diet. Also, people taking orlistat showed mild but consistent deficiencies of vitamins A, E, and beta-carotene. The drug's label is expected to include recommendations that users take a daily multivitamin. Orlistat can also lead to hepatitis, gallstones and kidney stones. It is not for people who have problems absorbing food, or for those who have had organ transplants. Also, anyone taking blood-thinning medicines or being treated for diabetes or thyroid disease should consult a physician before using orlistat.

In a six-month company study, moderately overweight patients who used 60 milligrams of the weight loss drug along with diet and exercise lost an average of 4 pounds more than patients who used diet and exercise alone.

As reported in the, the FDA's director of nonprescription products stressed that this OTC product is strictly intended only for use along with diet and exercise programs. "Using this drug alone is unlikely to be beneficial," he said at a telebriefing.

Although the FDA approved OTC orlistat based on the review of the sponsor's safety data and after consideration by an FDA advisory committee, Dr. Sidney M. Wolfe, director of Public Citizen's Health Research Group, called the approval "the height of recklessness." Wolfe said studies have associated the prescription version of the drug with precancerous lesions of the colon. He has also called for withdrawal of the prescription version of orlistat. (, Feb 8, 2007)


Phenylpropanolamine (PPA)

This drug is associated with hemorrhagic stroke. Most drugs containing this ingredient have been reformulated, but there are still a small number of cold remedies and weight loss drugs sold OTC with this ingredient. Pseudoephedrine is an effective decongestant and alternative to PPA for use in cold and flu preparations, but, there is no approved alternative to the OTC drug for use in appetite suppressants. Therefore, if you are using any OTC medications to suppress your appetite for weight loss or other reasons, you should stop using the medicine and talk to your doctor about getting a prescription drug instead.


Ephedra also called Ma huang. The Food and Drug Administration (FDA) issued a final rule in Feb 2004 prohibiting the sale of dietary supplements containing ephedrine alkaloids (ephedra) which had been extensively promoted for aiding weight control and boosting sports performance and energy. There had been little evidence of ephedra's effectiveness except for modest, short-term weight loss without any clear health benefit, while confirming that the substance raises blood pressure and otherwise stresses the circulatory system. These effects are linked to significant adverse health outcomes, including heart attack and stroke.(3)


Chromium has long been of interest for its possible connection to various health conditions (diabetes, lowering blood lipid levels, promoting weight loss, and improving body composition). However, controlled studies of chromium supplementation in all of of these conditions have been inconclusive and controversial. (4) Few serious adverse effects have been linked to high intakes of chromium, however certain commonly used medications may interact with chromium, especially when taken on a regular basis. Before taking dietary supplements, check with your doctor or other qualified healthcare provider, especially if you take prescription or over-the-counter medications. The National Institute of Health advises that eating a variety of whole grains, fruits, vegetables, meats, and milk and milk products should provide sufficient chromium(4).

In testing conducted in 2008, the FDA has found these ingredients illegally added to some products being sold in the United States. These ingredients were not identified on the label.

Sibutramine is a Schedule IV controlled substance and the active pharmaceutical ingredient in Meridia, an approved prescription drug to treat obesity.

Some of the identified products recommend taking more than 3 times the recommended daily dosage of sibutramine.  Because of this, even consumers without a history of health problems that take these high doses of sibutramine may suffer serious adverse effects if they take these products, such as increased blood pressure, tachycardia, palpitations, and seizure. 

Populations who would be at increased risk of serious adverse health effects from consuming a standard dose of sibutramine include:

  • Patients with a history of hypertension, especially those with uncontrolled or poorly controlled hypertension.
  • Patients with a history of coronary artery disease, congestive heart failure, arrhythmias, or stroke.
  • Patients with narrow angle glaucoma.
  • Patients with a history of seizure.
  • Patients predisposed to bleeding events and those taking concomitant medications known to affect hemostasis or platelet function.
  • Patients with severe hepatic dysfunction.
  • Patients concurrently taking the following medications:
    • Sumatriptan
    • Dihydroergotamine
    • Dextromethorphan
    • Meperidine,
    • Pentazocine
    • Fentanyl
    • Lithium
    • Tryptophan
    • MAO inhibitors

Rimonabant is the active pharmaceutical ingredient in Zimulti which has not been approved in the United States.  In Europe the drug is known as Acomplia.

In June 2007, the FDA Endocrinologic and Metabolic Drugs Advisory Committee unanimously voted not to recommend approval of the drug because of increased risk of neurological and psychiatric side effects—seizures, depression, anxiety, insomnia, aggressiveness, and suicidal thoughts among patients.  In June of 2008, the Medicines and Healthcare Products Regulatory Agency of the United Kingdom linked rimonabant to 5 deaths and 720 adverse reactions over the past two years.  In October, the European Medicines Agency recommended that marketing and sales of Accomplia be suspended due to safety concerns. 


Phenolphthalein was an ingredient in some Over-the-Counter laxative products until 1999 when the FDA reclassified the drug as “not generally recognized as safe and effective” after studies indicated that phenolphthalein presented a potential carcinogenic risk. Phenolphthalein has also been found to be genotoxic in that it can damage or cause mutations to DNA. 


Phenytoin is the active pharmaceutical ingredient in Dilantin, an approved anti-seizure medication.  Because there were trace amounts of this drug in some of these products, the risk was not assessed.  However, these products could pose a risk to consumers who are allergic or hypersensitive to phenytoin.


Bumetanide is a the active pharmaceutical ingredient in Bumex, a prescription diuretic.  Potential risks associated with the use of Bumetanide include serious and significant fluid and electrolyte loss and an elevation in uric acid concentrations. Consumers should not take Bumetanide if they are allergic to sulfonamides. Significant drug interactions, such as taking bumetanide with digoxin and lithium, may lead to an increased risk of toxicity. Patients may also be at an increased risk of hypotension (low blood pressure), fainting, and resultant injury if they have normal blood pressure or are already taking an antihypertensive medication. The risk of toxic reactions to the drug may be greater in elderly consumers or consumers with impaired renal function(7).

Read more:


(1) Phenylpropanolamine (PPA) from the FDA
(2) Herbal Chart (seizures) from the Epilepsy Coalition from New York State
(3) Dietary Supplements, Warnings and Safety Information, from the FDA
(4) Chromium: Dietary Supplement Fact Sheet from the NIH, Office of Dietary Supplements, August 2005
(5) Over-the-Counter Medicines, What's Right for You? from the FDA
(6) Kava Consumer Advisory from the FDA
(7) FDA's Initiative Against Contaminated Weight Loss Products, FDA, January 2009

Written by N Thompson, MSN, ARNP - Last updated January 2009

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