{"id":631503,"date":"2025-03-04T10:40:34","date_gmt":"2025-03-04T15:40:34","guid":{"rendered":"https:\/\/www.singlecare.com\/blog\/?p=631503"},"modified":"2025-10-22T19:39:46","modified_gmt":"2025-10-22T23:39:46","slug":"qsymia-vs-phentermine","status":"publish","type":"post","link":"https:\/\/www.singlecare.com\/blog\/qsymia-vs-phentermine\/","title":{"rendered":"Qsymia vs. phentermine: Differences, similarities & side effects"},"content":{"rendered":"

Qsymia<\/span><\/a> and <\/span>phentermine<\/span><\/a> are medications commonly prescribed for weight loss. Qsymia is a brand-name drug that contains two active ingredients, phentermine and extended-release topiramate. Phentermine is a generic drug, commonly known by brand names <\/span>Adipex-P<\/span><\/a> and <\/span>Lomaira<\/span><\/a>. While both drugs are commonly used for weight management, they are not exactly the same. Continue reading to learn more about Qsymia and phentermine.\u00a0\u00a0<\/span><\/p>\n

RELATED: <\/b>Where can I get phentermine?<\/b><\/a><\/p>\n

Qsymia vs. phentermine: Key differences<\/span><\/h2>\n

Qsymia contains two active ingredients: phentermine and extended-release topiramate. It is a brand-name drug in the form of oral capsules taken once daily. There is no generic for Qsymia at this time. Phentermine, which is one of the two active ingredients in Qsymia, also exists as its own medication in generic form as well as brand-names <\/span>Adipex-P<\/span><\/a> and <\/span>Lomaira<\/span><\/a>. Phentermine is available as oral capsules and tablets.\u00a0<\/span><\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n
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Compare Qsymia vs. phentermine key differences<\/span><\/h2>\n<\/th>\n<\/tr>\n<\/thead>\n

<\/td>\nQsymia<\/b><\/td>\nPhentermine<\/b><\/td>\n<\/tr>\n
Drug class<\/b><\/td>\nSympathomimetic amine anorectic (appetite suppressant)\/anticonvulsant<\/span><\/td>\nSympathomimetic amine anorectic (appetite suppressant)<\/span><\/td>\n<\/tr>\n
Brand\/generic status<\/b><\/td>\nBrand<\/span><\/td>\nGeneric; also available as brand-name<\/span><\/td>\n<\/tr>\n
Generic or brand name<\/b><\/td>\nNo generic available at this time<\/span><\/td>\nBrand names Adipex-P and Lomaira\u00a0<\/span><\/td>\n<\/tr>\n
What form(s) does the drug come in?<\/b><\/td>\nOral capsules<\/span><\/td>\nOral capsules<\/span><\/p>\n

Oral tablets<\/span><\/td>\n<\/tr>\n

What is the standard dosage?<\/b><\/td>\nStarting <\/span>dose<\/span><\/a> is 3.75 mg\/23 mg (phentermine\/topiramate) by mouth once daily for 14 days, then the prescribing healthcare provider will gradually increase the dose to a maximum dose of 15 mg\/92 mg by mouth once daily<\/span><\/td>\nThe <\/span>dose<\/span><\/a> of phentermine is 15 to 37.5 mg by mouth once daily; or 8 mg by mouth 3 times daily<\/span><\/td>\n<\/tr>\n
How long is the typical treatment?<\/b><\/td>\nLong-term\u00a0<\/span><\/td>\nShort-term, although some healthcare providers prescribe it longer-term with close monitoring<\/span><\/td>\n<\/tr>\n
Who typically uses the medication?<\/b><\/td>\nAdults and pediatric patients 12 years and older<\/span><\/td>\nAdults 17 years and older<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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Qsymia vs. phentermine: Conditions treated<\/span><\/h2>\n

Qsymia is approved by the Food and Drug Administration (FDA) for weight loss and long-term weight management in adults and pediatric patients 12 years and older with <\/span>obesity<\/span><\/a>. It is also FDA approved for use in adults who are overweight and have at least one weight-related medical condition, such as <\/span>Type 2 diabetes<\/span><\/a>, <\/span>high blood pressure<\/span><\/a>, or <\/span>high cholesterol<\/span><\/a>.\u00a0<\/span><\/p>\n

While Qsymia is FDA approved for long-term use, phentermine as a single-ingredient drug is FDA-approved for short-term use in weight loss. It is approved in adults 17 years and older with obesity (with a starting body mass index, or BMI, of 30 or more) or who are overweight (starting BMI of 27 or more) with other weight-related conditions. Although phentermine is FDA approved for short-term use only, healthcare providers sometimes prescribe it <\/span>off-label<\/span><\/a> (for non-FDA-approved use) for <\/span>long-term weight management<\/span><\/a>.\u00a0<\/span><\/p>\n

Healthcare providers typically recommend lifestyle changes, including a reduced-calorie diet and increased physical activity, in combination with Qsymia or phentermine.\u00a0<\/span><\/p>\n\n\n\n\n\n\n\n
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Compare Qsymia vs. phentermine conditions treated<\/span><\/h2>\n<\/th>\n<\/tr>\n<\/thead>\n

Condition<\/b><\/td>\nQsymia<\/b><\/td>\nPhentermine<\/b><\/td>\n<\/tr>\n
Weight loss and long-term weight management\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\nOff-label\u00a0<\/span><\/td>\n<\/tr>\n
Weight loss (short-term use)<\/span><\/td>\nNo\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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Is Qsymia better than phentermine?<\/span><\/h2>\n

There are no studies that directly compare Qsymia with phentermine alone. Phentermine alone works by reducing appetite, which decreases food consumption\u2014and other metabolic effects may play a role. Qsymia contains phentermine, so it works the same way, but it <\/span>also<\/span><\/a> contains the active ingredient topiramate, which is thought to work by suppressing appetite and increasing feelings of fullness.\u00a0<\/span><\/p>\n

In a <\/span>study on Qsymia<\/span><\/a>, people lost up to 10% of their starting body weight after 13 months. Up to 70% of people lost at least 5% of their starting body weight, and about half lost at least 10% of their starting body weight.\u00a0<\/span><\/p>\n

In a <\/span>review of clinical trials<\/span><\/a> lasting from two to 24 weeks, people taking phentermine lost about 14 pounds.<\/span><\/p>\n

Currently, weight loss drugs like <\/span>Wegovy (semaglutide) and Zepbound (tirzepatide)<\/span><\/a> are very popular. While both drugs are effective, a <\/span>study published in December 2024<\/span><\/a> found that, on average, people who used Zepbound lost an average of 20.2% of body weight compared to 13.7% in those who used Wegovy.<\/span><\/p>\n

Consult your healthcare provider for more information and medical advice about the best medication for you\u2014as the best medicine depends on individual factors like your medical history, current conditions, and other medicines you take that could interact with Qsymia or phentermine.\u00a0<\/span><\/p>\n

Qsymia vs. phentermine: Insurance coverage and cost comparison<\/span><\/h2>\n

Qsymia may be covered by insurance plans, depending on the plan. You can check the <\/span>manufacturer’s website<\/span><\/a> for more information on insurance coverage as well as other savings options. Phentermine may or may not be covered, depending on the plan. Medicare prescription plans do not typically cover weight loss drugs like Qsymia or phentermine.\u00a0\u00a0<\/span><\/p>\n

For individuals paying out-of-pocket, a 30-day supply of Qsymia costs about $274. You can use a <\/span>free SingleCare coupon<\/span><\/a> to pay as low as $173, saving about $100 per month on this drug.<\/span><\/p>\n

Without insurance, generic phentermine costs about $51 for a one-month supply. However, you can use a <\/span>free SingleCare coupon<\/span><\/a> to pay as low as $10 for this drug, saving about $41 per month.<\/span><\/p>\n\n\n\n\n\n\n\n\n\n
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Compare Qsymia vs. phentermine cost and coverage<\/span><\/h2>\n<\/th>\n<\/tr>\n<\/thead>\n

<\/td>\nQsymia<\/b><\/td>\nPhentermine<\/b><\/td>\n<\/tr>\n
Typically covered by insurance?<\/b><\/td>\nVaries\u00a0<\/span><\/td>\nVaries\u00a0<\/span><\/td>\n<\/tr>\n
Typically covered by Medicare Part D?<\/b><\/td>\nNo\u00a0<\/span><\/td>\nNo\u00a0<\/span><\/td>\n<\/tr>\n
Quantity<\/b><\/td>\n30, 7.5\/46 mg capsules<\/span><\/td>\n30, 37.5 mg tablets<\/span><\/td>\n<\/tr>\n
SingleCare cost*<\/b><\/td>\n$173<\/span><\/td>\n$10<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
*Cost at time of publication. Drug prices fluctuate and vary by pharmacy and location.\u00a0<\/span><\/h5>\n

Qsymia vs. phentermine: Side effects<\/span><\/h2>\n

The most common side effects of Qsymia include numbness and tingling, dizziness, altered taste, <\/span>insomnia<\/span><\/a>, constipation, and dry mouth.\u00a0<\/span><\/p>\n

Phentermine is chemically similar to amphetamine and thus has some similar <\/span>side effects<\/span><\/a> to stimulant drugs like <\/span>Adderall<\/span><\/a>. Some of the common side effects of phentermine include palpitations, increased blood pressure, fast heart rate, overstimulation, restlessness, insomnia, mood changes, shaking, headache, <\/span>dry mouth<\/span><\/a>, altered taste, changes in libido, and stomach issues like diarrhea or constipation. (Although Qsymia also contains phentermine, the dose of phentermine in Qsymia is lower than the typical dose used in phentermine alone. As a result, the risk of stimulant-like side effects may be reduced when using Qsymia compared to taking phentermine by itself.)<\/span><\/p>\n

The table below lists some of the more common side effects of Qsymia and phentermine. The frequency varies by dosage, with higher doses generally causing a higher frequency of side effects. This is not a full list of potential side effects. For more information on side effects or to discuss any concerns, consult your healthcare provider.\u00a0<\/span><\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n
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Compare Qsymia vs. phentermine side effects<\/span><\/h2>\n<\/th>\n<\/tr>\n<\/thead>\n

<\/td>\nQsymia<\/b><\/td>\nPhentermine<\/b><\/td>\n<\/tr>\n
Side effect<\/b><\/td>\nApplicable?<\/b><\/td>\nFrequency<\/b><\/td>\nApplicable?<\/b><\/td>\nFrequency<\/b><\/td>\n<\/tr>\n
Numbness and tingling<\/span><\/td>\nYes\u00a0<\/span><\/td>\n4\u201320%<\/span><\/td>\nNo\u00a0<\/span><\/td>\nN\/A<\/span><\/td>\n<\/tr>\n
Dizziness\u00a0<\/span><\/td>\nYes<\/span><\/td>\n3\u20139%<\/span><\/td>\nYes\u00a0<\/span><\/td>\nNot supplied<\/span><\/td>\n<\/tr>\n
Altered taste<\/span><\/td>\nYes<\/span><\/td>\n1\u20139%<\/span><\/td>\nYes\u00a0<\/span><\/td>\nNot supplied<\/span><\/td>\n<\/tr>\n
Insomnia\u00a0<\/span><\/td>\nYes<\/span><\/td>\n5\u20139%<\/span><\/td>\nYes\u00a0<\/span><\/td>\nNot supplied<\/span><\/td>\n<\/tr>\n
Constipation\u00a0<\/span><\/td>\nYes<\/span><\/td>\n8\u201316%<\/span><\/td>\nYes\u00a0<\/span><\/td>\nNot supplied<\/span><\/td>\n<\/tr>\n
Dry mouth\u00a0<\/span><\/td>\nYes<\/span><\/td>\n7\u201319%<\/span><\/td>\nYes\u00a0<\/span><\/td>\nNot supplied<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Source: <\/span>Qsymia (DailyMed)<\/span><\/a>, <\/span>Adipex-P (DailyMed)<\/span><\/a><\/h5>\n

Qsymia vs. phentermine: Drug interactions<\/span><\/h2>\n

Before taking Qsymia or phentermine, tell your healthcare provider about all of the medicines you take. This includes prescription and over-the-counter (OTC) drugs, vitamins, and dietary supplements.\u00a0<\/span><\/p>\n

Phentermine (and Qsymia, which contains phentermine) should never be taken within 14 days of taking a drug in the monoamine oxidase inhibitor (<\/span>MAOI<\/span><\/a>) class of drugs because of the risk of hypertensive crisis (a sudden, severe increase in blood pressure). Neither phentermine nor Qsymia should be combined with <\/span>alcohol<\/span><\/a>. Also, people who use <\/span>insulin<\/span><\/a> or take oral medication to lower blood sugar may require lower doses of their blood sugar-lowering medicines when taking phentermine or Qsymia.\u00a0<\/span><\/p>\n

Qsymia, due to its topiramate component, has some additional interactions, such as <\/span>birth control pills<\/span><\/a>. This interaction does not tend to increase the risk of pregnancy but may result in spotting. Other Qsymia interactions include central nervous system (CNS) depressants, <\/span>amitriptyline<\/span><\/a>, and certain <\/span>anticonvulsants<\/span><\/a>, among others.\u00a0<\/span><\/p>\n

This is not a full list of drug interactions, and others may occur. Consult your healthcare provider for more information about drug interactions and how they may affect you.\u00a0<\/span><\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
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Compare Qsymia vs. phentermine drug interactions<\/span><\/h2>\n<\/th>\n<\/tr>\n<\/thead>\n

Drug<\/b><\/td>\nDrug class<\/b><\/td>\nInteracts with Qsymia?<\/b><\/td>\nInteracts with\u00a0 Phentermine?<\/b><\/td>\n<\/tr>\n
Phenelzine\u00a0<\/span><\/p>\n

Tranylcypromine\u00a0<\/span><\/td>\n

MAOI\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\n<\/tr>\n
Alcohol\u00a0<\/span><\/td>\nAlcohol\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\n<\/tr>\n
Lantus\u00a0<\/span><\/p>\n

Novolog\u00a0<\/span><\/p>\n

Tresiba\u00a0\u00a0<\/span><\/td>\n

Insulin\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\n<\/tr>\n
Glipizide\u00a0<\/span><\/p>\n

Glyburide\u00a0<\/span><\/td>\n

Oral diabetes medications\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\n<\/tr>\n
Kariva<\/span><\/p>\n

Ocella<\/span><\/p>\n

Sprintec<\/span><\/td>\n

Oral contraceptives (birth control pills)<\/span><\/td>\nYes\u00a0<\/span><\/td>\nNo\u00a0<\/span><\/td>\n<\/tr>\n
Phenobarbital\u00a0<\/span><\/p>\n

Benzodiazepines such as Xanax (alprazolam)<\/span><\/p>\n

Sleep medications such as Ambien (zolpidem)<\/span><\/td>\n

CNS depressants\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\nNo\u00a0<\/span><\/td>\n<\/tr>\n
Carbamazepine\u00a0<\/span><\/p>\n

Phenytoin\u00a0<\/span><\/p>\n

Valproic acid\u00a0<\/span><\/td>\n

Anticonvulsants\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\nNo\u00a0<\/span><\/td>\n<\/tr>\n
Amitriptyline\u00a0<\/span><\/td>\nTricyclic antidepressant\u00a0<\/span><\/td>\nYes\u00a0<\/span><\/td>\nNo\u00a0<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

 <\/p>\n

Phentermine vs. Qsymia: Drug warnings<\/span><\/h2>\n

Be sure to tell your healthcare provider about your medical history and all current medical conditions before taking phentermine or Qsymia.<\/span><\/p>\n

You should not take phentermine or Qsymia if:<\/span><\/p>\n