Fastin Side Effects
Generic name: phentermine
Medically reviewed by Drugs.com. Last updated on Nov 11, 2024.
Note: This document provides detailed information about Fastin Side Effects associated with phentermine. Some dosage forms listed on this page may not apply specifically to the brand name Fastin.
Applies to phentermine: oral capsule, oral tablet.
Serious side effects of Fastin
Along with its needed effects, phentermine (the active ingredient contained in Fastin) 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 while taking phentermine:
Rare side effects
- seeing, hearing, or feeling things that are not there
- severe mental changes
Incidence not known
- chest pain
- decreased ability to exercise
- dizziness
- fainting
- fast, irregular, pounding, or racing heartbeat or pulse
- headache
- numbness or tingling in the arms or legs
- swelling of the feet or lower legs
- trembling or shaking of the legs, arms, hands, or feet
- trouble breathing
- trouble with thinking, speaking, or walking
- weakness
Other side effects of Fastin
Some side effects of phentermine 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:
Incidence not known
- decreased interest in sexual intercourse
- difficulty having a bowel movement (stool)
- dry mouth
- false or unusual sense of well-being
- hives or welts, itching, or skin rash
- inability to have or keep an erection
- increased in sexual ability, desire, drive, or performance
- increased interest in sexual intercourse
- loss in sexual ability, desire, drive, or performance
- redness of the skin
- unpleasant taste
For healthcare professionals
Applies to phentermine: compounding powder, oral capsule, oral capsule extended release, oral tablet, oral tablet disintegrating.
General adverse events
The more commonly reported adverse reactions have included palpitations, restlessness, insomnia, and headache.
Cardiovascular
- Frequency not reported: Regurgitant cardiac valvular disease, primary pulmonary hypertension, palpitations, tachycardia, elevated blood pressure, precordial pain, ischemic events, angina, myocardial infarction, cardiac failure, cardiac arrest[Ref]
Nervous system
- Frequency not reported: Overstimulation, restlessness, nervousness, dizziness, euphoria, dysphoria, tremor, headache, fatigue, cerebrovascular events[Ref]
Psychiatric
- Frequency not reported: Insomnia, psychosis, impotence, libido changes, depression, hallucinations[Ref]
Hypersensitivity
Gastrointestinal
- Frequency not reported: Dry mouth, unpleasant taste, diarrhea, constipation, other gastrointestinal disturbances, nausea, vomiting, abdominal cramps[Ref]
Dermatologic
- Frequency not reported: Rash[Ref]
Genitourinary
- Frequency not reported: Micturition disturbances[Ref]
Other
- Frequency not reported: Facial edema[Ref]
References
1. Cerner Multum, Inc. "Australian Product Information."
2. (2016) "Product Information. Phentermine Hydrochloride (phentermine)." Teva Pharmaceuticals USA
3. (2016) "Product Information. Adipex-P (phentermine)." Teva Pharmaceuticals (formerly Gate Pharmaceuticals)
4. (2016) "Product Information. Lomaira (phentermine)." KVK-Tech Inc
Frequently asked questions
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Further information
Fastin side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.