benzphetamine
Benzphetamine, formerly known by its brand name Didrex, is a prescription appetite suppressant that's used with diet and exercise to help adults with weight loss. It's classified as a sympathomimetic medication and is also a Schedule III controlled substance. Benzphetamine is currently available only as a generic tablet that's taken by mouth once per day. Side effects include high blood pressure, trouble sleeping, and restlessness.
What is Benzphetamine?
What is Benzphetamine used for?
Short-term treatment for weight management in adults with a body mass index (BMI) of 30 kg/m2 or greater
How Benzphetamine works
Benzphetamine is a sympathomimetic (stimulant). The exact way it works to help with weight loss isn't well understood. But it's thought to lower your appetite by raising the levels of certain chemicals in your brain that control hunger.
Drug facts
Risks and warnings for Benzphetamine
Benzphetamine can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Not safe with other weight loss medications
Benzphetamine shouldn't be used within 1 year of taking other medications for weight loss, including ones found over the counter. This is because of a higher risk of serious side effects, like heart or breathing problems. Talk with your care team if you have more questions about your treatment plan.
Lower response to the medication over time
Benzphetamine isn't meant for long-term use because you can develop tolerance, meaning that it stops working over time. Raising the dose of benzphetamine won't help and isn't safe because of the risk for serious side effects. Let your prescriber know if you've noticed weight gain or your appetite returning after you've been taking this medication. They'll need to recommend other treatment options for you.
Risk of misuse and dependence
- Risk factors: Taking more benzphetamine than prescribed
Similar to other stimulants, benzphetamine has a risk of misuse and for causing dependence, which can lead to stimulant use disorder. To lower this risk, your healthcare professional will usually prescribe a limited amount at a time. Take benzphetamine exactly as directed. It's meant for short-term use, typically just a few weeks. If interested, talk with your care team to learn more about long-term weight management options.
High blood pressure in the lungs (pulmonary hypertension)
- Risk factors: Taking benzphetamine for longer than 3 months
Although rare, benzphetamine can cause pulmonary hypertension, or high blood pressure in the lungs. Pulmonary hypertension is serious and can be life-threatening. The risk is higher if you take medications that lower your appetite, including benzphetamine, for longer than 3 months. If you experience trouble breathing, chest pain, fainting, or swelling in your legs, stop the medication and get medical help right away.
Heart valve problem
- Risk factors: Long-term use | Taking high doses | Taking multiple medications that lower your appetite
People taking stimulants similar to benzphetamine experienced heart valve problems. The risk is higher for those using the medication long-term or taking multiple appetite-suppressing medications. Let your prescriber know if you have dizziness, chest pain, leg or ankle swelling, irregular heartbeat, fatigue, or trouble breathing.
Risk of high blood pressure
Let your prescriber know if you have high blood pressure, even if your condition is well-controlled by medications. Taking benzphetamine might raise your risk for high blood pressure so your care team might ask you to check your blood pressure more often during treatment.
Risk of low blood sugar in people with diabetes
- Risk factors: Taking insulin
People with diabetes who are taking medications that lower blood sugar like insulin are at higher risk for low blood sugar during treatment with benzphetamine. This can happen due to changes in eating habits and appetite with benzphetamine. Your diabetes care team might need to adjust the dose of your blood sugar medications after you start benzphetamine.
Always keep emergency glucose tablets or hard candy with you in case your blood sugar drops too low. If you experience symptoms of low blood sugar, such as feeling faint, shaking, and sweating, check and treat your low blood sugar levels right away. If your symptoms don't improve, get medical help.
Side effects of Benzphetamine
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
- Fast heartbeat
- High blood pressure
- Feeling overstimulated
- Restlessness or shakiness
- Dizziness
- Trouble sleeping
- Sweating
Less Common Side Effects
- Headache
- Dry mouth
- Having a bad taste in your mouth
- Nausea
- Diarrhea
- Change in sex drive
Benzphetamine serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Heart valve problems: dizziness, chest pain, leg or ankle swelling, irregular heartbeat, fatigue, trouble breathing
- High blood pressure in the lungs: trouble breathing, chest pain, fainting, swelling in the legs
The following Benzphetamine side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
Agitation
confusion
dizziness
fast, irregular, pounding, or racing heartbeat or pulse
feeling lightheaded or faint
headache
hives, welts, itching, skin rash
irritability
lightheadedness
mood or other mental changes
nervousness
nightmares
numbness or tingling in the arms or legs
redness of the skin
restlessness
seizures
shakiness or trembling in the legs, arms, hands, or feet
sweating
trouble sleeping
trouble thinking, speaking, or walking
unusual feeling of excitement
Rare
Chest discomfort or pain
discouragement
feeling sad or empty
hallucinations
lack of appetite
loss of interest or pleasure
severe mental changes
swelling of the feet or lower legs
trouble breathing
trouble concentrating
unusual tiredness or weakness
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Blurred vision
change in consciousness
dark-colored urine
dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
loss of consciousness
muscle cramps, spasms, pain, or stiffness
nervousness
physical attempt to injure oneself
pounding in the ears
rapid, shallow breathing
severe anxiety or feeling of panic
stomach cramps
violent actions
vomiting
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Decrease in sexual ability, desire, drive, or performance
decreased interest in sexual intercourse
inability to have or keep an erection
increase in sexual ability, desire, drive, or performance
increased interest in sexual intercourse
unpleasant taste
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
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Pros and cons of Benzphetamine
Pros
- Taken by mouth once per day
- Available as a lower-cost generic medication
Cons
- Risk of misuse and dependency
- Doesn't have a lot of clinical evidence or experience
Pharmacist tips for Benzphetamine
- Take benzphetamine by mouth once per day with or without food in the mid-morning or mid-afternoon. Taking it too late in the day can cause trouble sleeping.
- Benzphetamine should be used along with diet and exercise for the best weight loss results. Work with your care team to create a healthy diet and regular exercise plan that suits you.
- Since benzphetamine lowers your appetite, it can raise your risk of low blood sugar (hypoglycemia) if you have diabetes and take medications like insulin. Let your diabetes specialist know you're taking benzphetamine, they might need to adjust your diabetes medications and recommend that you check your blood sugar more.
- Since benzphetamine affects the brain, it can make tasks like driving harder. Avoid certain activities until you know how this medication affects you.
- Benzphetamine interacts with several medications, such as monoamine oxidase inhibitors (MAOIs). Tell your prescriber about all the medications you're taking before starting benzphetamine, as well as any you plan to take during treatment. They can make sure your medications are safe for you.
- If you're pregnant or thinking of getting pregnant, avoid taking benzphetamine. Speak with your primary care provider about how to maintain a healthy weight during pregnancy. Weight loss during pregnancy can cause harm to unborn babies.
- It's not known if benzphetamine is safe to take while breastfeeding. Similar stimulant medications are known to pass into breast milk and can potentially cause serious side effects in your baby. Talk to your prescriber or OB-GYN about the risks and benefits of taking this medication while breastfeeding.
Common questions about Benzphetamine
Since benzphetamine is a fairly old medication, there isn't a lot of available clinical evidence for it. A study from 1961 showed people taking benzphetamine lost 1 pound per week over almost 4 months. But the amount of weight you'll lose and how quickly it happens depends on many things. Talk to your care team if you have more questions about what to expect with benzphetamine.
It takes about 1 to 2 days for most of benzphetamine to leave your body. This time frame is estimated based on the half-life of this medication.
Both benzphetamine and phentermine (Adipex-P, Lomaira) are stimulant medications used short-term for weight loss. In general, there's more experience with phentermine because there are more studies available. Talk to your care team if you have more questions about the differences between these medications.
It's unclear why the brand medication Didrex was discontinued, but it wasn't due to safety or efficacy concerns.
Yes, benzphetamine is still available as a generic by a prescription from a healthcare professional (HCP).
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Benzphetamine dosage
Typical dosage for Benzphetamine
The typical starting dose is 25 mg or 50 mg by mouth once per day, preferably in the mid-morning or mid-afternoon. Based on your response, your prescriber might adjust the dose between 25 mg to 50 mg by mouth, one to three times per day.
Interactions between Benzphetamine and other drugs
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Furazolidone
- Iproniazid
- Isocarboxazid
- Linezolid
- Methylene Blue
- Moclobemide
- Nialamide
- Phenelzine
- Procarbazine
- Rasagiline
- Safinamide
- Selegiline
- Sibutramine
- Tranylcypromine
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Abiraterone Acetate
- Acetazolamide
- Alfentanil
- Almotriptan
- Aluminum
- Amifampridine
- Amineptine
- Amitriptyline
- Amitriptylinoxide
- Amoxapine
- Anileridine
- Benzhydrocodone
- Benzthiazide
- Brompheniramine
- Buprenorphine
- Bupropion
- Buspirone
- Butorphanol
- Calcium Carbonate
- Carbamazepine
- Chlorothiazide
- Chlorpheniramine
- Citalopram
- Clomipramine
- Cocaine
- Codeine
- Cyclobenzaprine
- Desipramine
- Desvenlafaxine
- Dexlansoprazole
- Dextromethorphan
- Diazoxide
- Dibenzepin
- Difenoxin
- Dihydrocodeine
- Dihydroxyaluminum Aminoacetate
- Diphenoxylate
- Dolasetron
- Donepezil
- Doxepin
- Duloxetine
- Eletriptan
- Escitalopram
- Esomeprazole
- Ethylmorphine
- Fenfluramine
- Fentanyl
- Fluoxetine
- Fluvoxamine
- Frovatriptan
- Granisetron
- Hydrochlorothiazide
- Hydrocodone
- Hydroflumethiazide
- Hydromorphone
- Hydroxytryptophan
- Imipramine
- Iobenguane I 131
- Ketobemidone
- Lansoprazole
- Lasmiditan
- Levomilnacipran
- Levorphanol
- Lithium
- Lofepramine
- Lorcaserin
- Magaldrate
- Magnesium Carbonate
- Melitracen
- Meperidine
- Metaxalone
- Methadone
- Milnacipran
- Mirtazapine
- Morphine
- Morphine Sulfate Liposome
- Nalbuphine
- Naratriptan
- Nefazodone
- Nicomorphine
- Nortriptyline
- Omeprazole
- Ondansetron
- Opipramol
- Opium
- Opium Alkaloids
- Oxycodone
- Oxymorphone
- Palonosetron
- Pantoprazole
- Papaveretum
- Paregoric
- Paroxetine
- Pentazocine
- Piritramide
- Polythiazide
- Protriptyline
- Quinidine
- Rabeprazole
- Remifentanil
- Ritonavir
- Rizatriptan
- Sertraline
- Sodium Bicarbonate
- St John's Wort
- Sufentanil
- Sumatriptan
- Tapentadol
- Terbinafine
- Tianeptine
- Tilidine
- Tramadol
- Trazodone
- Trichlormethiazide
- Trimipramine
- Tryptophan
- Venlafaxine
- Vilazodone
- Vortioxetine
- Xipamide
- Ziprasidone
- Zolmitriptan
How much does Benzphetamine cost?
$33.66
Benzphetamine contraindications
Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Benzphetamine will not be safe for you to take.
- Heart problems (e.g., coronary artery disease, stroke, irregular heartbeat, uncontrolled high blood pressure, congestive heart failure)
- Currently take or have taken a monoamine oxidase inhibitors (MAOI) in the last 14 days
- Using other weight-loss medications
- Overactive thyroid (hyperthyroidism)
- Glaucoma
- Feeling agitated or distressed
- History of substance use disorder
- Currently pregnant or breastfeeding
What are alternatives to Benzphetamine?
Short-term treatment for weight management in adults with a body mass index (BMI) of 30 kg/m2 or greater
Short-term treatment for weight management in adults with a body mass index (BMI) of:
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