Common Phentermine Side Effects


The most commonly reported Phentermine side effects (click to view or check a box to report):

Dyspnoea (27)
Pain (22)
Anxiety (22)
Chest Pain (20)
Nausea (19)
Abdominal Pain Upper (16)
Headache (16)
Cholelithiasis (15)
Mitral Valve Incompetence (15)
Abdominal Pain (15)
Blood Pressure Increased (14)
Cholecystitis Chronic (14)
Pulmonary Embolism (14)
Vomiting (13)
Ventricular Fibrillation (13)
Myocardial Infarction (13)
Injury (13)
Deep Vein Thrombosis (12)
Loss Of Consciousness (12)
Dizziness (12)

➢ More



If you or someone in your family has experienced a serious side effect to a health product, you are encouraged to report the experience to your health care professional (e.g. physician, pharmacist). You could also complete a copy of the side effect reporting form or report your side effect to FDA.

Phentermine Side Effects Reported to FDA



Phentermine Side Effect Report#9931777
Urine Flow Decreased
This is a report of a 61-year-old male patient (weight: NA) from US, suffering from the following health symptoms/conditions: weight control, who was treated with Phentermine (dosage: 1 Pill Once Daily, start time:
Jan 30, 2014), combined with: NA. and developed a serious reaction and side effect(s): Urine Flow Decreased after the beginning of treatment. This case can indicate the possible existence of increased vulnerability to Phentermine treatment in male patients, resulting in Urine Flow Decreased side effect.
Phentermine Side Effect Report#9925479
Benign Prostatic Hyperplasia, Insomnia
This report suggests a potential Phentermine Benign Prostatic Hyperplasia side effect(s) that can have serious consequences. A 59-year-old male patient (weight: NA) from US was diagnosed with the following symptoms/conditions: weight control and used Phentermine (dosage: NA) starting
Jun 02, 2013. After starting Phentermine the patient began experiencing various side effects, including: Benign Prostatic Hyperplasia, InsomniaAdditional drugs used concurrently: NA. Although Phentermine demonstrated significant improvements in a number of clinically relevant cases, troublesome symptoms, such as Benign Prostatic Hyperplasia, may still occur.
Phentermine Side Effect Report#9886203
Asthenia
This Asthenia problem was reported by a consumer or non-health professional from US. A female patient (weight: NA) was diagnosed with the following symptoms/conditions: weight increased. On NS this consumer started treatment with Phentermine Hcl Tablets (dosage: NA). The following drugs were being taken at the same time: NA. When using Phentermine Hcl Tablets, the patient experienced the following unwanted symptoms/side effects: AstheniaAlthough all drugs are carefully tested before they are licensed for use, they carry side effect risks. Some side effects, such as Asthenia, may become evident only after a product is in use by the general population.
Phentermine Side Effect Report#9886200
Tongue Ulceration, Abdominal Pain Upper, Tongue Disorder, Dry Mouth
This Tongue Ulceration side effect was reported by a consumer or non-health professional from US. A 61-year-old female patient (weight:NA) experienced the following symptoms/conditions: NA.The patient was prescribed Phentermine Hcl Tablets (drug dosage: NA), which was initiated on 201305. Concurrently used drugs:
  • Furosemide Tablets
.After starting to take Phentermine Hcl Tablets the consumer reported adverse symptoms, such as: Tongue Ulceration, Abdominal Pain Upper, Tongue Disorder, Dry MouthThese side effects may potentially be related to Phentermine Hcl Tablets.
Phentermine Side Effect Report#9886190
Mitral Valve Incompetence
This is a report of a 45-year-old female patient (weight: NA) from US, suffering from the following health symptoms/conditions: overweight, who was treated with Phentermine Hcl Tablets (dosage: NA, start time: 201209), combined with: NA. and developed a serious reaction and side effect(s): Mitral Valve Incompetence after the beginning of treatment. This case can indicate the possible existence of increased vulnerability to Phentermine Hcl Tablets treatment in female patients, resulting in Mitral Valve Incompetence side effect.
Phentermine Side Effect Report#9803359
Cardio-respiratory Arrest, Toxicity To Various Agents
This report suggests a potential Phentermine Cardio-respiratory Arrest side effect(s) that can have serious consequences. A 53-year-old female patient (weight: NA) from US was diagnosed with the following symptoms/conditions: NA and used Phentermine (dosage: NA) starting NS. After starting Phentermine the patient began experiencing various side effects, including: Cardio-respiratory Arrest, Toxicity To Various AgentsAdditional drugs used concurrently:
  • Diazepam
  • Oxymorphone
The patient was hospitalized. Although Phentermine demonstrated significant improvements in a number of clinically relevant cases, troublesome symptoms, such as Cardio-respiratory Arrest, may still occur.
Phentermine Side Effect Report#9803097
Completed Suicide
This Completed Suicide problem was reported by a pharmacist from US. A 64-year-old female patient (weight: NA) was diagnosed with the following symptoms/conditions: NA. On NS this consumer started treatment with Phentermine (dosage: NA). The following drugs were being taken at the same time: NA. When using Phentermine, the patient experienced the following unwanted symptoms/side effects: Completed SuicideAlthough all drugs are carefully tested before they are licensed for use, they carry side effect risks. Some side effects, such as Completed Suicide, may become evident only after a product is in use by the general population.
Phentermine Side Effect Report#9744140
Pneumomediastinum
This Pneumomediastinum side effect was reported by a physician from US. A 24-year-old male patient (weight:NA) experienced the following symptoms/conditions: weight decreased.The patient was prescribed Phentermine (drug dosage: 3 Pills Over The Prior Week), which was initiated on NS. Concurrently used drugs: NA..After starting to take Phentermine the consumer reported adverse symptoms, such as: PneumomediastinumThese side effects may potentially be related to Phentermine. The patient was hospitalized.
Phentermine Side Effect Report#9687595
Subarachnoid Haemorrhage, Cerebrovascular Accident
This is a report of a 31-year-old female patient (weight: NA) from US, suffering from the following health symptoms/conditions: NA, who was treated with Phentermine (dosage: NA, start time: NS), combined with: NA. and developed a serious reaction and side effect(s): Subarachnoid Haemorrhage, Cerebrovascular Accident after the beginning of treatment. This case can indicate the possible existence of increased vulnerability to Phentermine treatment in female patients, resulting in Subarachnoid Haemorrhage side effect.
Phentermine Side Effect Report#9687594
Cerebrovascular Accident
This report suggests a potential Phentermine Cerebrovascular Accident side effect(s) that can have serious consequences. A 41-year-old female patient (weight: NA) from US was diagnosed with the following symptoms/conditions: NA and used Phentermine (dosage: NA) starting NS. After starting Phentermine the patient began experiencing various side effects, including: Cerebrovascular AccidentAdditional drugs used concurrently: NA. Although Phentermine demonstrated significant improvements in a number of clinically relevant cases, troublesome symptoms, such as Cerebrovascular Accident, may still occur.
Phentermine Side Effect Report#9677419
Cholelithiasis
This Cholelithiasis problem was reported by a consumer or non-health professional from US. A 33-year-old female patient (weight: NA) was diagnosed with the following symptoms/conditions: weight increased. On 201203 this consumer started treatment with Phentermine Hcl Tablets (dosage: 18.25 Mg). The following drugs were being taken at the same time: NA. When using Phentermine Hcl Tablets, the patient experienced the following unwanted symptoms/side effects: CholelithiasisAlthough all drugs are carefully tested before they are licensed for use, they carry side effect risks. Some side effects, such as Cholelithiasis, may become evident only after a product is in use by the general population.
Phentermine Side Effect Report#9677412
Fatigue, Acne, Therapeutic Response Unexpected
This Fatigue side effect was reported by a consumer or non-health professional from US. A female patient (weight:NA) experienced the following symptoms/conditions: weight control.The patient was prescribed Phentermine Hcl Tablets (drug dosage: NA), which was initiated on 201207. Concurrently used drugs: NA..After starting to take Phentermine Hcl Tablets the consumer reported adverse symptoms, such as: Fatigue, Acne, Therapeutic Response UnexpectedThese side effects may potentially be related to Phentermine Hcl Tablets.
Phentermine Side Effect Report#9677409
Pain, Oedema Peripheral, Blood Pressure Increased
This is a report of a 53-year-old female patient (weight: NA) from US, suffering from the following health symptoms/conditions: decreased appetite, who was treated with Phentermine Hcl Tablets (dosage: 18.75mg, start time:
Oct 18, 2011), combined with: NA. and developed a serious reaction and side effect(s): Pain, Oedema Peripheral, Blood Pressure Increased after the beginning of treatment. This case can indicate the possible existence of increased vulnerability to Phentermine Hcl Tablets treatment in female patients, resulting in Pain side effect.
Phentermine Side Effect Report#9559405
Spinal Cord Infarction, Blood Glucose Increased, Glycosylated Haemoglobin Increased, Vasoconstriction
This report suggests a potential Phentermine Spinal Cord Infarction side effect(s) that can have serious consequences. A 33-year-old female patient (weight: NA) from US was diagnosed with the following symptoms/conditions: obesity and used Phentermine (dosage: NA) starting NS. After starting Phentermine the patient began experiencing various side effects, including: Spinal Cord Infarction, Blood Glucose Increased, Glycosylated Haemoglobin Increased, VasoconstrictionAdditional drugs used concurrently: NA.The patient was hospitalized. Although Phentermine demonstrated significant improvements in a number of clinically relevant cases, troublesome symptoms, such as Spinal Cord Infarction, may still occur.
Phentermine Side Effect Report#9536745
Hypertension, Nausea, Dyspnoea, Angina Pectoris
This Hypertension problem was reported by a pharmacist from US. A 49-year-old male patient (weight: NA) was diagnosed with the following symptoms/conditions: weight decreased. On
Jul 01, 2013 this consumer started treatment with Phentermine (dosage: NA). The following drugs were being taken at the same time: NA. When using Phentermine, the patient experienced the following unwanted symptoms/side effects: Hypertension, Nausea, Dyspnoea, Angina PectorisThe patient was hospitalized.Although all drugs are carefully tested before they are licensed for use, they carry side effect risks. Some side effects, such as Hypertension, may become evident only after a product is in use by the general population.
Phentermine Side Effect Report#9511200
Colitis Ischaemic
This Colitis Ischaemic side effect was reported by a health professional from US. A 36-year-old female patient (weight:NA) experienced the following symptoms/conditions: weight decreased.The patient was prescribed Phentermine (drug dosage: NA), which was initiated on NS. Concurrently used drugs: NA..After starting to take Phentermine the consumer reported adverse symptoms, such as: Colitis IschaemicThese side effects may potentially be related to Phentermine. The patient was hospitalized.
Phentermine Side Effect Report#9492188
Ventricular Fibrillation, Arteriospasm Coronary, Electrocardiogram St Segment Elevation, Mitral Valve Incompetence
This is a report of a 70-year-old female patient (weight: NA) from US, suffering from the following health symptoms/conditions: NA, who was treated with Phentermine (dosage: Unk, start time: NS), combined with:
  • Metformin (Unk)
  • Omeprazole (Unk)
  • Calcium Vitamin D (Unk)
and developed a serious reaction and side effect(s): Ventricular Fibrillation, Arteriospasm Coronary, Electrocardiogram St Segment Elevation, Mitral Valve Incompetence after the beginning of treatment. This case can indicate the possible existence of increased vulnerability to Phentermine treatment in female patients, resulting in Ventricular Fibrillation side effect. The patient was hospitalized.
Phentermine Side Effect Report#9490788
Colitis Ischaemic
This report suggests a potential Phentermine Hydrochloride 37.5 Mg Tablet Colitis Ischaemic side effect(s) that can have serious consequences. A 36-year-old female patient (weight: NA) from US was diagnosed with the following symptoms/conditions: weight decreased and used Phentermine Hydrochloride 37.5 Mg Tablet (dosage: Qd) starting
Feb 23, 2011. After starting Phentermine Hydrochloride 37.5 Mg Tablet the patient began experiencing various side effects, including: Colitis IschaemicAdditional drugs used concurrently: NA.The patient was hospitalized. Although Phentermine Hydrochloride 37.5 Mg Tablet demonstrated significant improvements in a number of clinically relevant cases, troublesome symptoms, such as Colitis Ischaemic, may still occur.
Phentermine Side Effect Report#9478514
Colitis Ischaemic
This Colitis Ischaemic problem was reported by a physician from US. A 36-year-old female patient (weight: NA) was diagnosed with the following symptoms/conditions: weight control. On NS this consumer started treatment with Phentermine Hcl (dosage: NA). The following drugs were being taken at the same time: NA. When using Phentermine Hcl, the patient experienced the following unwanted symptoms/side effects: Colitis IschaemicAlthough all drugs are carefully tested before they are licensed for use, they carry side effect risks. Some side effects, such as Colitis Ischaemic, may become evident only after a product is in use by the general population.
Phentermine Side Effect Report#9476629
Haemorrhagic Stroke, Retinal Artery Occlusion
This Haemorrhagic Stroke side effect was reported by a health professional from US. A 41-year-old female patient (weight:NA) experienced the following symptoms/conditions: NA.The patient was prescribed Phentermine (drug dosage: NA), which was initiated on NS. Concurrently used drugs: NA..After starting to take Phentermine the consumer reported adverse symptoms, such as: Haemorrhagic Stroke, Retinal Artery OcclusionThese side effects may potentially be related to Phentermine.
Phentermine Side Effect Report#9476624
Haemorrhagic Stroke, Subarachnoid Haemorrhage, Nausea, Vomiting, Headache, Muscular Weakness
This is a report of a 31-year-old female patient (weight: NA) from US, suffering from the following health symptoms/conditions: medical diet, who was treated with Phentermine (dosage: NA, start time: NS), combined with: NA. and developed a serious reaction and side effect(s): Haemorrhagic Stroke, Subarachnoid Haemorrhage, Nausea, Vomiting, Headache, Muscular Weakness after the beginning of treatment. This case can indicate the possible existence of increased vulnerability to Phentermine treatment in female patients, resulting in Haemorrhagic Stroke side effect.
Phentermine Side Effect Report#9470705
Cerebrovascular Accident
This report suggests a potential Phentermine Cerebrovascular Accident side effect(s) that can have serious consequences. A 41-year-old female patient (weight: NA) from US was diagnosed with the following symptoms/conditions: NA and used Phentermine (dosage: NA) starting NS. After starting Phentermine the patient began experiencing various side effects, including: Cerebrovascular AccidentAdditional drugs used concurrently: NA. Although Phentermine demonstrated significant improvements in a number of clinically relevant cases, troublesome symptoms, such as Cerebrovascular Accident, may still occur.
Phentermine Side Effect Report#9470697
Cerebrovascular Accident
This Cerebrovascular Accident problem was reported by a health professional from US. A 31-year-old female patient (weight: NA) was diagnosed with the following symptoms/conditions: NA. On NS this consumer started treatment with Phentermine (dosage: NA). The following drugs were being taken at the same time: NA. When using Phentermine, the patient experienced the following unwanted symptoms/side effects: Cerebrovascular AccidentAlthough all drugs are carefully tested before they are licensed for use, they carry side effect risks. Some side effects, such as Cerebrovascular Accident, may become evident only after a product is in use by the general population.
Phentermine Side Effect Report#9464341
Colitis Ischaemic
This Colitis Ischaemic side effect was reported by a health professional from US. A 36-year-old female patient (weight:NA) experienced the following symptoms/conditions: NA.The patient was prescribed Phentermine (drug dosage: For Two Years), which was initiated on NS. Concurrently used drugs: NA..After starting to take Phentermine the consumer reported adverse symptoms, such as: Colitis IschaemicThese side effects may potentially be related to Phentermine. The patient was hospitalized.
Phentermine Side Effect Report#9461354
Neuropathy Peripheral, Cyanosis, Peripheral Coldness, Hyperhidrosis, Peripheral Vascular Disorder
This is a report of a 67-year-old male patient (weight: NA) from US, suffering from the following health symptoms/conditions: weight control, who was treated with Phentermine (dosage: 37.5mg 1 Pill Once A Day Once A Day By Mouth, start time:
Mar 05, 2013), combined with:
  • Atenolol
  • Hctz
  • Cymbalta
  • Benicar
  • Percocet
and developed a serious reaction and side effect(s): Neuropathy Peripheral, Cyanosis, Peripheral Coldness, Hyperhidrosis, Peripheral Vascular Disorder after the beginning of treatment. This case can indicate the possible existence of increased vulnerability to Phentermine treatment in male patients, resulting in Neuropathy Peripheral side effect. The patient was hospitalized.


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The appearance of Phentermine on this list does not mean that FDA has concluded that the drug has the listed risk. It means that FDA has identified a potential safety issue, but it does not mean that FDA has found a causal relationship between the drug and the listed risk.

What are common Phentermine Side Effects for Women?

Women Side Effects Reports
Dyspnoea 26
Anxiety 22
Pain 21
Chest Pain 18
Abdominal Pain Upper 16
Nausea 16
Cholelithiasis 15
Headache 15
Mitral Valve Incompetence 15
Abdominal Pain 14

What are common Phentermine Side Effects for Men?

Men Side Effects Reports
Pneumomediastinum 5
Renal Failure Acute 3
Rhabdomyolysis 3
Alanine Aminotransferase Increased 2
Aspartate Aminotransferase Increased 2
Back Pain 2
Blood Urine Present 2
Calculus Urinary 2
Cardiac Arrest 2
Cardio-respiratory Arrest 2

Track Your Side Effects

Note Your Observations

It is really important to keep track of your health symptoms, right from the time you start a new medicine. You can do it any way you prefer: in a notebook, in a computer file or using our online tool. You should also note down any other medicines you are taking at the same time, because there could be an interaction between these medicines.

Why Your Notes are Important

Your notes could be helpful in several ways:

  • You can use them to remind you of details that may alert your health care professional(s) to a problem
  • You will have a record to refer to in the future, in case you are ever prescribed the same medicine again

  • Log Form

    You can use the following log form to write down important information, like the date and time you experienced a side effect and your symptoms, how strong the symptoms were, and any other medicines you were using.

    Medicine Name and Dosage:
    Side Effects Scale Date & Time Other Medicine(s) or Treatment(s)
    Scale: 1 = very mild to 10 = very bad

    Side effects reports are analyzed to discover potential health product safety signals. Some important reactions may take an extremely long time to develop or occur infrequently. Continued monitoring of adverse reactions is thus essential to maintain a comprehensive safety and effectiveness profile of health products.

    You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

    Phentermine reports list potential signals of serious risks and new safety information that were identified using the FDA Adverse Event Reporting System (FAERS).
    FAERS is a database that contains information on adverse event and medication errors reports submitted to FDA by healthcare professionals (such as physicians, pharmacists, nurses and others), consumers (such as patients, family members, layers and others) and manufacturers.

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    Phentermine Safety Alerts, Active Ingredients, Usage Information

    NDC 0093-2109
    Type HUMAN PRESCRIPTION DRUG
    Proprietary Name Phentermine Hydrochloride
    Name Phentermine Hydrochloride
    Dosage Form CAPSULE
    Route ORAL
    On market since 20111003
    Labeler Teva Pharmaceuticals USA Inc
    Active Ingredient(s) PHENTERMINE HYDROCHLORIDE
    Strength(s) 30
    Unit(s) mg/1
    Pharma Class Appetite Suppression [PE],Increased Sympathetic Activity [PE],Sympathomimetic Amine Anorectic [EPC]

    Phentermine Dosage, Warnings, Usage.

    Side Effects reported to FDA: 278

    Phentermine safety alerts: No

    Reported deaths: 15

    Reported hospitalizations: 107

    Latest Phentermine clinical trials

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