Phentermine and topiramate

What Phentermine and topiramate is used for

Quoted from the “Indications and Usage” section of the FDA-approved label.

Phentermine and topiramate extended-release capsules are indicated in combination with a reduced-calorie diet and increased physical activity to reduce excess body weight and maintain weight reduction long term in …

— FDA label: Phentermine and Topiramate, Prasco Laboratories, effective May 18, 2026. Read the full label on DailyMed →

Label quoted: the one for the most common form (capsule, extended release, oral), Phentermine and Topiramate, Prasco Laboratories; it covers 4 products in the FDA NDC Directory. The side effects, interactions, dosage and pregnancy quotes below come from this same label.

The FDA has 4 labels for products of this medicine (different makers and forms); uses can differ between them. Check the label that comes with your own medicine.

This page is not medical advice. Talk to your doctor or pharmacist before you start, stop or change any medicine.

Conditions named on the label

These condition names appear word for word in the label’s “Indications and Usage” text (matched with a reviewed table). Each page lists hospitals whose own websites name the condition.

Related medical specialties

Boxed warning

A boxed warning (“black box”) is the FDA’s strongest warning on a drug label, for serious or life-threatening risks.

The label quoted above has no boxed warning.

0 of 4 FDA labels for this medicine have a boxed warning.

Phentermine and topiramate side effects

Quoted from the “Adverse Reactions” section of the FDA-approved label. Tell your doctor about any side effect that worries you.

The following clinically significant adverse reactions are described elsewhere in the labeling: Embryo-Fetal Toxicity [see Warnings and Precautions (5.1) and Use in Specific Populations (8.1, 8.6)] Suicidal Behavior and Ideation [see Warnings and Precautions (5.2)] Risk of Ophthalmologic Adverse Reactions [see Warnings and Precautions (5.3)] Mood and Sleep Disorders [see Warnings and Precautions (5.4)] Cognitive Impairment [see Warnings and Precautions (5.5)] Slowing of …

— FDA label: Phentermine and Topiramate, Prasco Laboratories, effective May 18, 2026. This is part of the section. Read the full label on DailyMed →

Phentermine and topiramate drug interactions

Quoted from the “Drug Interactions” section of the FDA-approved label. Tell your pharmacist about every medicine, vitamin and herbal product you take.

Table 5 displays clinically significant drug interactions with phentermine and topiramate extended-release capsules. Table 5. Clinically Significant Drug Interactions with Phentermine and Topiramate Extended-Release Capsules Monoamine Oxidase Inhibitors Clinical Impact Concomitant use of phentermine with monoamine oxidase inhibitors (MAOIs) increases the risk of hypertensive crisis.

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Intervention Concomitant use of phentermine and topiramate extended-release capsules are contraindicated during MAOI treatment and within 14 days of stopping an MAOI. Oral Contraceptives Clinical Impact Co-administration of multiple-dose phentermine and topiramate extended-release capsules 15 mg/92 mg once daily with a single dose of oral contraceptive containing 35 µg ethinyl estradiol (estrogen component) and 1 mg norethindrone (progestin component), in obese otherwise healthy volunteers, decreased the exposure of ethinyl estradiol by 16% and increased the exposure of norethindrone by 22% [see Clinical Pharmacology (12.3)]. Although this interaction is not anticipated to increase the risk of pregnancy, irregular bleeding (spotting) may occur more frequently due to both the increased exposure to the progestin and lower exposure to the estrogen, which tends to stabilize the endometrium. Intervention Inform patients not to discontinue their combination oral contraceptive if spotting occurs, but to notify their health care provider if the spotting is troubling to them. CNS Depressants Including Alcohol Clinical Impact The concomitant use of alcohol or CNS depressant drugs (e.g., barbiturates, benzodiazepines, and sleep medications) with phentermine or topiramate may potentiate CNS depression such as dizziness or cognitive adverse reactions, or other centrally mediated effects of these agents. Intervention Advise patients not to drive or operate machinery until they have gained sufficient experience on phentermine and topiramate extended-release capsules to gauge whether it adversely affects their mental performance, motor performance, and/or vision. Caution patients against excessive alcohol intake when taking phentermine and topiramate extended-release capsules. Consider phentermine and topiramate extended-release capsules dosage reduction or discontinuation if cognitive dysfunction persists [see Warnings and Precautions (5.5)] Non-Potassium Sparing Diuretics Clinical Impact Concurrent use of phentermine and topiramate extended-release capsules with non-potassium sparing diuretics may potentiate the potassium-wasting action of these diuretics. Concomitant administration of hydrochlorothiazide alone with topiramate alone has been shown to increase the C max and AUC of topiramate by 27% and 29%, respectively. Intervention When phentermine and topiramate extended-release capsules are used concomitantly with non-potassium-sparing diuretics, measure potassium before and during phentermine and topiramate extended-release capsules treatment [see Warnings and Precautions (5.12) and Clinical Pharmacology (12.3)].

— FDA label: Phentermine and Topiramate, Prasco Laboratories, effective May 18, 2026. This is part of the section. Read the full label on DailyMed →

Phentermine and topiramate dosage

Quoted from the “Dosage and Administration” section of the FDA-approved label. Your own dose is the one your doctor prescribes: do not change it on your own.

Take orally once daily in morning. Avoid administration in evening to prevent insomnia (2.2). Recommended starting dosage is 3.75 mg/23 mg (phentermine mg/topiramate mg) daily for 14 days; then increase to 7.5 mg/46 mg daily (2.2). Escalate dosage based on weight loss in adults or BMI reduction in pediatric patients. See the Full Prescribing Information for details regarding discontinuation or dosage escalation (2.2).

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Gradually discontinue 15 mg/92 mg dosage to prevent possible seizure (2.3). Do not exceed 7.5 mg/46 mg dosage for patients with moderate or severe renal impairment or patients with moderate hepatic impairment (2.4, 2.5). 2.1 Recommended Testing Prior to and During Treatment with Phentermine and Topiramate Extended-Release Capsules Prior to phentermine and topiramate extended-release capsules initiation and during treatment with phentermine and topiramate extended-release capsules, the following is recommended: Obtain a negative pregnancy test before initiating phentermine and topiramate extended-release capsules in patients who can become pregnant and monthly during phentermine and topiramate extended-release capsules therapy. Phentermine and topiramate extended-release capsules are contraindicated during pregnancy [see Contraindications (4), Warnings and Precautions (5.1), and Use in Specific Populations (8.3)]. Obtain a blood chemistry profile that includes bicarbonate, creatinine, and potassium in all patients, and glucose in patients with type 2 diabetes mellitus on antidiabetic medication prior to initiating phentermine and topiramate extended-release capsules treatment and periodically during treatment [see Warnings and Precautions (5.7, 5.8, 5.12)]. 2.2 Recommended Dosage and Administration The recommended dosage, titration, and administration of phentermine and topiramate extended-release capsules are as follows: Take phentermine and topiramate extended-release capsules orally once daily in the morning with or without food. Avoid administration of phentermine and topiramate extended-release capsules in the evening due to the possibility of insomnia. The recommended starting dosage of phentermine and topiramate extended-release capsules is one capsule (containing 3.75 mg of phentermine and 23 mg of topiramate) (3.75 mg/23 mg) taken orally once daily for 14 days; after 14 days increase to the recommended dosage of phentermine and topiramate extended-release capsules 7.5 mg/46 mg orally once daily. After 12 weeks of treatment with phentermine and topiramate extended-release capsules 7.5 mg/46 mg, evaluate weight loss for adults or BMI reduction for pediatric patients aged 12 years and older. If an adult patient has not lost at least 3% of baseline body weight or a pediatric patient has not experienced a reduction of at least 3% of baseline BMI, increase the dosage to phentermine and topiramate extended-release capsules 11.25 mg/69 mg orally once daily for 14 days; followed by an increase in the dosage to phentermine and topiramate extended-release capsules 15 mg/92 mg orally once daily.

— FDA label: Phentermine and Topiramate, Prasco Laboratories, effective May 18, 2026. This is part of the section. Read the full label on DailyMed →

Phentermine and topiramate in pregnancy

Quoted from the pregnancy part of the FDA-approved label. Ask your doctor before you take any medicine while pregnant or planning a pregnancy.

Risk Summary Phentermine and topiramate extended-release capsules are contraindicated in pregnant patients. The use of phentermine and topiramate extended-release capsules can cause fetal harm, and weight loss offers no clear clinical benefit to a pregnant patient (see Clinical Considerations).

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Available data from pregnancy registries and epidemiologic studies indicate an increased risk of major congenital malformations, including but not limited to cleft lip and/or cleft palate (oral clefts), and of being SGA in infants exposed in utero to topiramate (see Data). When phentermine and topiramate were co-administered to rats at doses of 3.75 and 25 mg/kg, respectively [approximately 2 times the maximum recommended human dose (MRHD) based on area under the curve (AUC)], or at the same dose to rabbits (approximately 0.1 times and 1 time, respectively, the clinical exposures at the MRHD based on AUC), there were no drug-related malformations. However, structural malformations, including craniofacial defects and reduced fetal weights occurred in offspring of multiple species of pregnant animals administered topiramate at clinically relevant doses (see Data). Advise pregnant women of the potential risk to a fetus. Clinical Considerations Disease Associated Maternal and/or Embryo/Fetal Risk Weight loss during pregnancy may result in fetal harm. Appropriate weight gain based on pre-pregnancy weight is currently recommended for all pregnant patients, including those who are already overweight or obese, due to the obligatory weight gain that occurs in maternal tissues during pregnancy. Maternal obesity increases the risk for congenital malformations, including neural tube defects, cardiac malformations, oral clefts, and limb reduction defects. Fetal/Neonatal Adverse Reactions Phentermine and topiramate extended-release capsules can cause metabolic acidosis [see Warnings and Precautions (5.7)]. The effect of topiramate-induced metabolic acidosis has not been studied in pregnancy; however, metabolic acidosis in pregnancy (due to other causes) can cause decreased fetal growth, decreased fetal oxygenation, and fetal death, and may affect the fetus' ability to tolerate labor. Data Human Data Data evaluating the risk of major congenital malformations, oral clefts, and being SGA with topiramate exposure during pregnancy is available from the North American Antiepileptic Drug (NAAED) Pregnancy Registry and from several larger retrospective epidemiologic studies. Major Congenital Malformations The NAAED Pregnancy Registry indicates an increased risk of major congenital malformations, including but not limited to oral clefts in infants exposed to topiramate during the first trimester of pregnancy. Other than oral clefts, no specific pattern of major congenital malformations or grouping of major congenital malformation types were observed.

— FDA label: Phentermine and Topiramate, Prasco Laboratories, effective May 18, 2026. This is part of the section. Read the full label on DailyMed →

When Phentermine and topiramate should not be used

Quoted from the “Contraindications” section of the FDA-approved label.

Phentermine and topiramate extended-release capsules are contraindicated in patients: Who are pregnant [see Warnings and Precautions (5.1) and Use in Specific Populations (8.1)] With glaucoma [see Warnings and Precautions (5.3)] With hyperthyroidism Taking or within 14 days of stopping a monoamine oxidase inhibitors [see Drug Interactions (7)] With known hypersensitivity to phentermine, topiramate or any of the excipients in phentermine and topiramate extended-release capsules, or idiosyncrasy to the sympathomimetic amines.

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Anaphylaxis and angioedema have occurred with topiramate [see Warnings and Precautions (5.15)]. Pregnancy (4) Glaucoma (4) Hyperthyroidism (4) Taking or within 14 days of stopping monoamine oxidase inhibitors (4) Known hypersensitivity to any component of phentermine and topiramate extended-release capsules or idiosyncrasy to sympathomimetic amines (4)

— FDA label: Phentermine and Topiramate, Prasco Laboratories, effective May 18, 2026. Read the full label on DailyMed →

Phentermine and topiramate overdose

Quoted from the “Overdosage” section of the FDA-approved label. If someone may have taken too much, call Poison Help at 1-800-222-1222 (or 911 in an emergency).

In the event of a significant overdose with phentermine and topiramate extended-release capsules, if the ingestion is recent, the stomach should be emptied immediately by gastric lavage or by induction of emesis. Appropriate supportive treatment should be provided according to the patient's clinical signs and symptoms.

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In the event of an overdose of phentermine and topiramate extended-release capsules, consider contacting the Poison Help line (1-800-222-1222) or a medical toxicologist for additional overdosage management recommendations. Acute overdose of phentermine may be associated with restlessness, tremor, hyperreflexia, rapid respiration, confusion, aggressiveness, hallucinations, and panic states. Fatigue and depression usually follow the central stimulation. Cardiovascular effects include arrhythmia, hypertension or hypotension, and circulatory collapse. Gastrointestinal symptoms include nausea, vomiting, diarrhea, and abdominal cramps. Fatal poisoning usually terminates in convulsions and coma. Manifestations of chronic intoxication with anorectic drugs include severe dermatoses, marked insomnia, irritability, hyperactivity, and personality changes. A severe manifestation of chronic intoxication is psychosis, often clinically indistinguishable from schizophrenia. Management of acute phentermine intoxication is largely symptomatic and includes lavage and sedation with a barbiturate. Acidification of the urine increases phentermine excretion. Intravenous phentolamine has been suggested for possible acute, severe hypertension, if this complicates phentermine overdosage. Topiramate overdose has resulted in severe metabolic acidosis. Other signs and symptoms include convulsions, drowsiness, speech disturbance, blurred vision, diplopia, impaired mentation, lethargy, abnormal coordination, stupor, hypotension, abdominal pain, agitation, dizziness, and depression. The clinical consequences were not severe in most cases, but deaths have been reported after overdoses involving topiramate. A patient who ingested a dose between 96 and 110 gm topiramate was admitted to hospital with coma lasting 20 to 24 hours followed by full recovery after 3 to 4 days. Hemodialysis is an effective means of removing topiramate from the body.

— FDA label: Phentermine and Topiramate, Prasco Laboratories, effective May 18, 2026. Read the full label on DailyMed →

Forms and how it is given

Same medicine, other forms and combinations

Prescription medicine pages on this site that share an active ingredient with this one, from the FDA NDC Directory. A combination is a different medicine: ask your pharmacist before you switch.

Other medicines with one of these active ingredients

• TopiramateTopamax, Qudexy XR · 302 products
• Phentermine hydrochlorideLomaira · 123 products

Companies that list this medicine

Labelers in the FDA NDC Directory: the company named on the package (maker or distributor), with the number of prescription products.

• Teva Pharmaceuticals, Inc.4 products
• Vivus LLC4 products
• Prasco Laboratories4 products
• Dr.Reddys Laboratories Inc4 products

FDA approval history

• NDA: New Drug Application: how a new (usually brand-name) medicine is approved.
• ANDA: Abbreviated New Drug Application: how a generic version is approved.

Generic approvals (2)

• ANDA204982Actavis Labs Fl Inc · June 25, 2024
• ANDA208175DR Reddys Labs SA · June 12, 2025

Shortage status

The FDA drug shortage list does not show these products.

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Recalls

No recall linked to these products (by their NDC code) appears in the FDA enforcement reports.

Official identifiers

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• Teva Pharmaceuticals, Inc.Maker or distributor
• Vivus LLCMaker or distributor
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Sources

1. FDA-approved label on DailyMed (National Library of Medicine) — Phentermine and Topiramate, Prasco Laboratories, effective May 18, 2026; via openFDA, FDA data exported October 30, 2026, retrieved October 31, 2026
2. NDC Directory (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
3. Drugs@FDA (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
4. Drug recall enforcement reports (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 27, 2026, retrieved October 31, 2026
5. Drug shortages (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026

openFDA data is provided by the FDA as is; it may be incomplete. Always rely on the label that comes with your medicine. FDA Enforcement Report search →

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