Phentrmn/topiramat 11.25-69mg ER CP
It is used to help with weight loss in certain people.
Drug Class
Weight management agent
Pharmacologic Class
Sympathomimetic amine (Phentermine); Anticonvulsant, Carbonic Anhydrase Inhibitor (Topiramate)
Pregnancy Category
Category X
FDA Approved
Jul 2012
DEA Schedule
Schedule IV
Overview
What is this medicine?
This medication is a combination of two drugs, phentermine and topiramate, used to help with weight loss. Phentermine helps reduce your appetite, and topiramate helps you feel full and may reduce cravings. It's used along with a reduced-calorie diet and increased physical activity.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. To minimize sleep disturbances, avoid taking this medication late in the day. Unless your doctor advises you to limit fluid intake, drink plenty of non-caffeinated liquids.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep the container tightly closed to maintain its effectiveness.
Missing a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. To minimize sleep disturbances, avoid taking this medication late in the day. Unless your doctor advises you to limit fluid intake, drink plenty of non-caffeinated liquids.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep the container tightly closed to maintain its effectiveness.
Missing a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Follow a reduced-calorie diet as advised by your healthcare provider or dietitian.
- Increase your physical activity level gradually and consistently.
- Drink plenty of fluids to help prevent kidney stones and stay hydrated.
- Avoid alcohol, as it can increase side effects like dizziness and drowsiness.
- Do not drive or operate machinery until you know how this medication affects you, as it can cause dizziness, vision problems, or difficulty concentrating.
- Use effective contraception if you are a woman of childbearing potential, as this medication can cause serious birth defects.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 3.75 mg phentermine/23 mg topiramate ER orally once daily in the morning for 14 days. Then, increase to 7.5 mg phentermine/46 mg topiramate ER orally once daily. If after 12 weeks on 7.5 mg/46 mg, weight loss is <3%, increase to 11.25 mg phentermine/69 mg topiramate ER daily for 14 days, then 15 mg phentermine/92 mg topiramate ER daily. Discontinue if <5% weight loss after 12 weeks on 15 mg/92 mg.
Dose Range:
3.75 - 15 mg
Condition-Specific Dosing:
discontinuation:
Gradual tapering is recommended to reduce the risk of seizures (due to topiramate withdrawal). Reduce dose every other day over at least 1 week. If patient is on 15 mg/92 mg, reduce to 7.5 mg/46 mg for 1 week, then discontinue.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established (Safety and efficacy not established in patients under 18 years of age for weight management.)
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed (CrCl >50 mL/min)
Moderate:
Maximum dose 7.5 mg phentermine/46 mg topiramate ER daily (CrCl 30-50 mL/min)
Severe:
Not recommended (CrCl <30 mL/min)
Dialysis:
Not recommended
Hepatic Impairment:
Mild:
No adjustment needed
Moderate:
Maximum dose 7.5 mg phentermine/46 mg topiramate ER daily
Severe:
Not recommended
Pharmacology
Mechanism of Action
Phentermine is a sympathomimetic amine that stimulates the release of norepinephrine from nerve terminals in the hypothalamus, leading to appetite suppression. It may also have some effect on dopamine and serotonin. Topiramate's exact mechanism for weight loss is not fully understood but is thought to involve multiple actions, including enhancement of GABAergic activity, antagonism of AMPA/kainate glutamate receptors, inhibition of carbonic anhydrase, and modulation of voltage-gated sodium channels, which may contribute to satiety and reduced food intake.
Pharmacokinetics
Absorption:
Bioavailability:
Phentermine: ~80-100%; Topiramate: ~81%
Tmax:
Phentermine: 6-8 hours; Topiramate: 9 hours (for ER formulation)
FoodEffect:
Phentermine: Minimal effect; Topiramate: No significant effect on absorption
Distribution:
Vd:
Phentermine: ~3.7 L/kg; Topiramate: ~0.6-0.8 L/kg
ProteinBinding:
Phentermine: ~17.5%; Topiramate: 13-17%
CnssPenetration:
Yes
Elimination:
HalfLife:
Phentermine: ~20 hours; Topiramate: ~21 hours
Clearance:
Phentermine: Primarily renal; Topiramate: Primarily renal
ExcretionRoute:
Renal
Unchanged:
Phentermine: ~60-80% (pH dependent); Topiramate: ~70% (unchanged)
Pharmacodynamics
OnsetOfAction:
Phentermine: Within hours; Topiramate: Gradual (weeks for full effect)
PeakEffect:
Not precisely defined for weight loss, typically observed over weeks to months of therapy.
DurationOfAction:
24 hours (due to ER formulation and half-lives)
Safety & Warnings
BLACK BOX WARNING
FETAL TOXICITY: Qsymia can cause fetal harm. Data from pregnancy registries and epidemiologic studies indicate that exposure to topiramate in pregnancy increases the risk of oral clefts (cleft lip with or without cleft palate). Pregnancy testing is recommended before initiating Qsymia in women of childbearing potential and monthly during therapy. Advise women of childbearing potential to use effective contraception during Qsymia therapy.
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of acidosis (too much acid in the blood), such as:
+ Confusion
+ Fast breathing
+ Fast heartbeat
+ Abnormal heartbeat
+ Severe stomach pain, upset stomach, or vomiting
+ Excessive sleepiness
+ Shortness of breath
+ Feeling extremely tired or weak
Signs of low potassium levels, such as:
+ Muscle pain or weakness
+ Muscle cramps
+ Abnormal heartbeat
Signs of a urinary tract infection (UTI), such as:
+ Blood in the urine
+ Burning or pain when passing urine
+ Frequent or urgent need to urinate
+ Fever
+ Lower stomach pain or pelvic pain
Fast or abnormal heartbeat
Confusion, difficulty focusing, or changes in behavior
Memory problems or loss
Trouble speaking
Trouble sleeping
Difficulty urinating or changes in urine output
Back pain, abdominal pain, or blood in the urine (may be signs of a kidney stone)
Patients taking this medication may be at a higher risk of suicidal thoughts or actions, especially if they have a history of such thoughts or actions. If you experience new or worsening symptoms such as depression, nervousness, restlessness, irritability, panic attacks, or mood changes, contact your doctor immediately. If you have suicidal thoughts or actions, seek help right away.
This medication may cause severe eye problems, potentially leading to permanent vision loss if left untreated. If you experience new eye symptoms such as blurred vision, changes in vision, eye pain, or eye redness, contact your doctor immediately.
A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may occur, which can cause serious health problems or death. Seek medical help immediately if you experience:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in your mouth, throat, nose, or eyes
Other Possible Side Effects
Most people do not experience significant side effects, but some may occur. If you experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Headache
Diarrhea or constipation
Dry mouth
Numbness or tingling
Dizziness, tiredness, or weakness
Changes in taste
Upset stomach
Common cold symptoms
Nose or throat irritation
Back pain
* Joint pain
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of acidosis (too much acid in the blood), such as:
+ Confusion
+ Fast breathing
+ Fast heartbeat
+ Abnormal heartbeat
+ Severe stomach pain, upset stomach, or vomiting
+ Excessive sleepiness
+ Shortness of breath
+ Feeling extremely tired or weak
Signs of low potassium levels, such as:
+ Muscle pain or weakness
+ Muscle cramps
+ Abnormal heartbeat
Signs of a urinary tract infection (UTI), such as:
+ Blood in the urine
+ Burning or pain when passing urine
+ Frequent or urgent need to urinate
+ Fever
+ Lower stomach pain or pelvic pain
Fast or abnormal heartbeat
Confusion, difficulty focusing, or changes in behavior
Memory problems or loss
Trouble speaking
Trouble sleeping
Difficulty urinating or changes in urine output
Back pain, abdominal pain, or blood in the urine (may be signs of a kidney stone)
Patients taking this medication may be at a higher risk of suicidal thoughts or actions, especially if they have a history of such thoughts or actions. If you experience new or worsening symptoms such as depression, nervousness, restlessness, irritability, panic attacks, or mood changes, contact your doctor immediately. If you have suicidal thoughts or actions, seek help right away.
This medication may cause severe eye problems, potentially leading to permanent vision loss if left untreated. If you experience new eye symptoms such as blurred vision, changes in vision, eye pain, or eye redness, contact your doctor immediately.
A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may occur, which can cause serious health problems or death. Seek medical help immediately if you experience:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in your mouth, throat, nose, or eyes
Other Possible Side Effects
Most people do not experience significant side effects, but some may occur. If you experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Headache
Diarrhea or constipation
Dry mouth
Numbness or tingling
Dizziness, tiredness, or weakness
Changes in taste
Upset stomach
Common cold symptoms
Nose or throat irritation
Back pain
* Joint pain
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Sudden vision changes or eye pain (seek immediate medical attention)
- Signs of metabolic acidosis: unusual tiredness, loss of appetite, fast or shallow breathing, irregular heartbeat, feeling cold
- Signs of kidney stones: severe pain in your side or back, blood in urine, painful urination
- New or worsening depression, anxiety, panic attacks, irritability, agitation, restlessness, aggression, or thoughts of self-harm/suicide (contact your doctor immediately)
- Increased heart rate or blood pressure (report to your doctor)
- Severe dizziness or fainting
- Numbness or tingling in your hands or feet that is severe or persistent
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following conditions and situations to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Describe the allergic reaction and its symptoms.
Certain health conditions, including:
+ Glaucoma
+ Overactive thyroid disease
+ Depression or a history of suicidal thoughts
+ Kidney disease
+ Liver disease
Medications you are currently taking, particularly:
+ Acetazolamide, dichlorphenamide, methazolamide, or zonisamide
+ Certain antidepressants or Parkinson's disease medications taken in the last 14 days, such as isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, as they may cause very high blood pressure
+ Linezolid or methylene blue
Pregnancy or potential pregnancy, as this medication is not recommended during pregnancy
Breast-feeding, as you should not breast-feed while taking this medication
The patient's age, as this medication is not approved for children under 12 years old
To ensure your safety, it is crucial to disclose all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, as well as any health problems. Your doctor and pharmacist need this information to assess potential interactions and determine the safety of taking this medication with your other treatments. Never start, stop, or change the dose of any medication without consulting your doctor.
It is essential to inform your doctor about the following conditions and situations to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Describe the allergic reaction and its symptoms.
Certain health conditions, including:
+ Glaucoma
+ Overactive thyroid disease
+ Depression or a history of suicidal thoughts
+ Kidney disease
+ Liver disease
Medications you are currently taking, particularly:
+ Acetazolamide, dichlorphenamide, methazolamide, or zonisamide
+ Certain antidepressants or Parkinson's disease medications taken in the last 14 days, such as isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, as they may cause very high blood pressure
+ Linezolid or methylene blue
Pregnancy or potential pregnancy, as this medication is not recommended during pregnancy
Breast-feeding, as you should not breast-feed while taking this medication
The patient's age, as this medication is not approved for children under 12 years old
To ensure your safety, it is crucial to disclose all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, as well as any health problems. Your doctor and pharmacist need this information to assess potential interactions and determine the safety of taking this medication with your other treatments. Never start, stop, or change the dose of any medication without consulting your doctor.
Precautions & Cautions
Important Warnings and Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Caution with Daily Activities
Avoid driving and engaging in activities that require alertness until you understand how this medication affects you.
Monitoring and Follow-up
Regularly check your blood work, blood pressure, and heart rate as instructed by your doctor. Additionally, follow the diet and exercise plan recommended by your doctor.
Stopping the Medication
Do not abruptly stop taking this medication without consulting your doctor, as this may increase the risk of seizures. If you need to stop taking this medication, your doctor will guide you on how to gradually discontinue it.
Interactions with Other Substances
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter (OTC) medications that may cause drowsiness, discuss the potential risks with your doctor.
Diabetes and Blood Sugar Control
If you have diabetes and take medications to lower your blood sugar, consult your doctor. Weight loss may increase the risk of low blood sugar, and you should be aware of the signs, such as dizziness, headache, fatigue, weakness, shaking, rapid heartbeat, confusion, hunger, or sweating. If you experience any of these symptoms, contact your doctor immediately.
High Blood Pressure
If you are being treated for high blood pressure, inform your doctor. Weight loss may increase the risk of low blood pressure, and you should be aware of the signs, such as severe dizziness or fainting. If you experience any of these symptoms, contact your doctor immediately.
Metabolic Acidosis
This medication may cause a condition called metabolic acidosis, which can be more likely in children, people with kidney problems, breathing difficulties, or diarrhea. The risk may also be higher if you take certain medications, undergo surgery, or follow a ketogenic diet. Over time, metabolic acidosis can lead to kidney stones, bone problems, or growth issues in children.
Allergies and Sensitivities
If you are allergic to tartrazine (FD&C Yellow No. 5), inform your doctor, as some products may contain this ingredient.
Heat-Related Risks
Be cautious in hot weather and during physical activity, as this medication can cause decreased sweating and increased body temperature, which may lead to hospitalization. If you experience a fever or decreased sweating, contact your doctor immediately.
Growth and Development
This medication may affect growth in children and teenagers. Regular growth checks may be necessary, and you should discuss this with your doctor.
Birth Control and Menstrual Changes
If you take birth control, your menstrual bleeding may change while taking this medication. Inform your doctor if you experience any changes.
Pregnancy and Birth Defects
A pregnancy test will be conducted to confirm that you are not pregnant before starting this medication and during treatment. The risk of birth defects is higher if this medication is taken during pregnancy, and the baby may be smaller at birth. It is not known if this leads to long-term problems. If you may become pregnant, you must use birth control while taking this medication. If you become pregnant, contact your doctor immediately.
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Caution with Daily Activities
Avoid driving and engaging in activities that require alertness until you understand how this medication affects you.
Monitoring and Follow-up
Regularly check your blood work, blood pressure, and heart rate as instructed by your doctor. Additionally, follow the diet and exercise plan recommended by your doctor.
Stopping the Medication
Do not abruptly stop taking this medication without consulting your doctor, as this may increase the risk of seizures. If you need to stop taking this medication, your doctor will guide you on how to gradually discontinue it.
Interactions with Other Substances
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter (OTC) medications that may cause drowsiness, discuss the potential risks with your doctor.
Diabetes and Blood Sugar Control
If you have diabetes and take medications to lower your blood sugar, consult your doctor. Weight loss may increase the risk of low blood sugar, and you should be aware of the signs, such as dizziness, headache, fatigue, weakness, shaking, rapid heartbeat, confusion, hunger, or sweating. If you experience any of these symptoms, contact your doctor immediately.
High Blood Pressure
If you are being treated for high blood pressure, inform your doctor. Weight loss may increase the risk of low blood pressure, and you should be aware of the signs, such as severe dizziness or fainting. If you experience any of these symptoms, contact your doctor immediately.
Metabolic Acidosis
This medication may cause a condition called metabolic acidosis, which can be more likely in children, people with kidney problems, breathing difficulties, or diarrhea. The risk may also be higher if you take certain medications, undergo surgery, or follow a ketogenic diet. Over time, metabolic acidosis can lead to kidney stones, bone problems, or growth issues in children.
Allergies and Sensitivities
If you are allergic to tartrazine (FD&C Yellow No. 5), inform your doctor, as some products may contain this ingredient.
Heat-Related Risks
Be cautious in hot weather and during physical activity, as this medication can cause decreased sweating and increased body temperature, which may lead to hospitalization. If you experience a fever or decreased sweating, contact your doctor immediately.
Growth and Development
This medication may affect growth in children and teenagers. Regular growth checks may be necessary, and you should discuss this with your doctor.
Birth Control and Menstrual Changes
If you take birth control, your menstrual bleeding may change while taking this medication. Inform your doctor if you experience any changes.
Pregnancy and Birth Defects
A pregnancy test will be conducted to confirm that you are not pregnant before starting this medication and during treatment. The risk of birth defects is higher if this medication is taken during pregnancy, and the baby may be smaller at birth. It is not known if this leads to long-term problems. If you may become pregnant, you must use birth control while taking this medication. If you become pregnant, contact your doctor immediately.
Overdose Information
Overdose Symptoms:
- Phentermine overdose: restlessness, tremor, rapid breathing, confusion, hallucinations, panic, high fever, muscle pain, weakness, dark urine, nausea, vomiting, diarrhea, stomach cramps, irregular heartbeat, high or low blood pressure, seizures, coma.
- Topiramate overdose: convulsions, drowsiness, speech disturbance, blurred vision, double vision, impaired coordination, lethargy, depression, abdominal pain, dizziness, metabolic acidosis, hypokalemia, coma.
What to Do:
Seek emergency medical attention or call Poison Help line at 1-800-222-1222. Treatment is supportive and symptomatic. Activated charcoal may be considered. Hemodialysis is effective for topiramate removal.
Drug Interactions
Contraindicated Interactions
- Monoamine Oxidase Inhibitors (MAOIs) (concurrent use or within 14 days of MAOI discontinuation)
- Glaucoma
- Hyperthyroidism
- Advanced arteriosclerosis
- Symptomatic cardiovascular disease (e.g., moderate to severe hypertension, heart failure, history of stroke, coronary artery disease)
- History of drug abuse
- Pregnancy
Major Interactions
- CNS depressants (e.g., alcohol, benzodiazepines, opioids) - increased CNS depression
- Oral contraceptives - decreased efficacy of oral contraceptives (due to topiramate)
- Carbonic anhydrase inhibitors (e.g., zonisamide, acetazolamide, methazolamide) - increased risk of metabolic acidosis and kidney stones
- Other weight loss agents (e.g., other sympathomimetic amines) - increased risk of adverse cardiovascular effects
- Antidiabetic agents (e.g., insulin, sulfonylureas) - potential for hypoglycemia (dose adjustment may be needed)
- Digoxin - phentermine may increase digoxin levels
- Lithium - topiramate may decrease lithium levels
Moderate Interactions
- Diuretics (e.g., hydrochlorothiazide) - increased risk of hypokalemia and metabolic acidosis
- Antiepileptic drugs (other) - potential for altered drug levels or increased side effects
- CNS stimulants (e.g., ADHD medications) - additive stimulant effects
Minor Interactions
- Not explicitly listed, but general caution with drugs affecting electrolyte balance or CNS.
Monitoring
Baseline Monitoring
Pregnancy test
Rationale: Contraindicated in pregnancy due to fetal risk (Category X).
Timing: Prior to initiation and monthly during therapy for women of childbearing potential.
Serum bicarbonate
Rationale: Risk of metabolic acidosis due to topiramate.
Timing: Prior to initiation.
Heart rate and blood pressure
Rationale: Phentermine can cause increases in heart rate and blood pressure.
Timing: Prior to initiation.
Renal function (CrCl)
Rationale: Dose adjustment required for renal impairment; drug is renally cleared.
Timing: Prior to initiation.
Electrolytes (e.g., potassium)
Rationale: Risk of hypokalemia, especially with diuretic use.
Timing: Prior to initiation.
Eye examination (for glaucoma)
Rationale: Topiramate can cause acute myopia and secondary angle-closure glaucoma.
Timing: Prior to initiation, especially in patients with risk factors.
Routine Monitoring
Weight
Frequency: Weekly/monthly, then at 12 weeks for dose adjustment decisions.
Target: Goal of 3-5% weight loss at 12 weeks.
Action Threshold: <3% weight loss at 12 weeks on 7.5 mg/46 mg (consider dose increase); <5% weight loss at 12 weeks on 15 mg/92 mg (discontinue).
Blood pressure and heart rate
Frequency: Regularly (e.g., monthly or at each visit).
Target: Maintain within normal limits.
Action Threshold: Significant or sustained increases (e.g., >10 mmHg systolic/diastolic, >10 bpm heart rate) may warrant dose reduction or discontinuation.
Serum bicarbonate
Frequency: Periodically (e.g., every 3-6 months or as clinically indicated).
Target: Maintain within normal limits.
Action Threshold: Persistent decreases below normal range may require dose reduction or discontinuation.
Renal function
Frequency: Periodically, especially in patients with pre-existing impairment or risk factors.
Target: Maintain stable function.
Action Threshold: Significant decline in CrCl may require dose adjustment or discontinuation.
Mental status/mood
Frequency: At each visit.
Target: Stable mood, absence of suicidal ideation.
Action Threshold: New or worsening depression, suicidal thoughts, or unusual behavioral changes require immediate evaluation.
Vision
Frequency: As clinically indicated, or if symptoms occur.
Target: Normal vision.
Action Threshold: Sudden decrease in visual acuity or eye pain requires immediate ophthalmologic evaluation.
Symptom Monitoring
- Increased heart rate
- Elevated blood pressure
- Dizziness
- Insomnia
- Constipation
- Dry mouth
- Paresthesia (tingling/numbness)
- Cognitive impairment (e.g., difficulty concentrating, memory problems)
- Mood changes (e.g., depression, anxiety, irritability)
- Suicidal thoughts or behavior
- Sudden decrease in visual acuity
- Eye pain
- Signs of kidney stones (e.g., flank pain, hematuria)
- Signs of metabolic acidosis (e.g., fatigue, anorexia, rapid breathing)
Special Patient Groups
Pregnancy
Contraindicated. This medication can cause serious birth defects (oral clefts) if used during pregnancy. Women of childbearing potential must have a negative pregnancy test before starting treatment and use effective contraception during therapy.
Trimester-Specific Risks:
First Trimester:
Highest risk of oral clefts (cleft lip/palate) with exposure during the first trimester.
Second Trimester:
Risk of other malformations or growth restriction not as well-established as first trimester, but still not recommended.
Third Trimester:
Risk of premature birth, low birth weight, and withdrawal symptoms in the neonate (e.g., irritability, tremor, hypertonia) due to phentermine.
Lactation
Not recommended. Both phentermine and topiramate are excreted in breast milk. Potential for serious adverse reactions in the breastfed infant (e.g., irritability, poor feeding, drowsiness, metabolic acidosis, diarrhea).
Infant Risk:
High (potential for irritability, poor feeding, drowsiness, metabolic acidosis, diarrhea, and other adverse effects).
Pediatric Use
Safety and efficacy have not been established in pediatric patients (under 18 years of age) for weight management. Use is not recommended.
Geriatric Use
Use with caution. Start at the lowest dose and titrate slowly. Elderly patients are more likely to have decreased renal function, which requires dose adjustment. Monitor for cardiovascular effects, cognitive impairment, and metabolic acidosis more closely.
Clinical Information
Clinical Pearls
- This medication is an adjunct to a reduced-calorie diet and increased physical activity; it is not a standalone solution for weight loss.
- Gradual titration is crucial to minimize side effects and improve tolerability.
- Discontinuation should be gradual to prevent withdrawal seizures (due to topiramate).
- Emphasize the importance of hydration to reduce the risk of kidney stones.
- Counsel patients on the potential for cognitive side effects ('topiramate fog') and paresthesia.
- Strict adherence to contraception is paramount for women of childbearing potential due to the teratogenic risk.
Alternative Therapies
- Liraglutide (Saxenda)
- Semaglutide (Wegovy)
- Naltrexone/Bupropion (Contrave)
- Orlistat (Xenical, Alli)
- Phentermine (Adipex-P, Lomaira)
- Setmelanotide (Imcivree - for specific genetic conditions)
Cost & Coverage
Average Cost:
Varies, typically $150-$250 per 30 capsules
Insurance Coverage:
Tier 2 or 3, often requires prior authorization and/or step therapy for weight loss indications.
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication.
This medication is accompanied by a Medication Guide, which provides crucial information about its use. Please read this guide carefully and review it again whenever you receive a refill. If you have any questions or concerns about this medication, don't hesitate to discuss them with your doctor, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount consumed, and the time it occurred.
This medication is accompanied by a Medication Guide, which provides crucial information about its use. Please read this guide carefully and review it again whenever you receive a refill. If you have any questions or concerns about this medication, don't hesitate to discuss them with your doctor, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount consumed, and the time it occurred.