Most people use prescription weight loss pills for a few weeks at a time and do not experience any significant phentermine withdrawal symptoms at the end of treatment.
However, if phentermine is taken for long periods of time, at high doses or abused it can be habit-forming. The resultant mental and physical dependence increases users’ chance of experiencing phentermine withdrawal symptoms. Unfortunately, some users also report phentermine withdrawal symptoms after just short-term use.
Phentermine Withdrawal Symptoms
Withdrawal occurs when an individual stops taking a medication or recreational drug after developing a physiological or psychological dependence (
- Severe tiredness or weakness (fatigue)
- Depression (or other mood changes)
- Insomnia (trouble sleeping or nightmares)
- Nausea or vomiting
- Stomach cramps or pain
Phentermine stimulates the central nervous system, which gives users a noticeable boost of energy throughout treatment. After stopping phentermine, some people experience feelings of weariness and fatigue due to the sudden lack of chemical stimulation.
If you are tired after stopping phentermine, take care to:
- Get enough sleep
- Fuel your body with healthy foods: avoid high-fat, high-carb and high-sugar goods that may worsen fatigue
- Stay lightly active
- Normal energy should return within a few days.
Phentermine affects natural levels of two neurotransmitters – norepinephrine and dopamine – that play a major role in mood regulation. After stopping phentermine, it can take a few days for the brain to readjust.
As a result, sadness and low mood are common phentermine withdrawal symptoms. For people with an underlying predisposition to anxiety, depression or other mental illnesses, these symptoms can prove particularly worrisome and harmful.
Depression, with or without suicidal ideation, is a very serious stimulant withdrawal symptom. If you are experiencing depression, a medical professional needs to know so that he/she can help you.
On the other hand, if you’re just feeling a little down, a short workout, talking to a friend or taking a moment for self-care can help can help life your mood.
Trouble falling and staying asleep is linked to phentermine use: both as a side effect while taking the medication and as a withdrawal symptom after stopping.
Since phentermine stimulates the nervous system, most patients recognize the cause of insomnia during treatment. However, depression – a problematic phentermine withdrawal symptom – can also cause severe sleep problems.
Nausea, Vomiting or Stomach Pain
Gastrointestinal symptoms like nausea, vomiting and stomach pain are common reactions when someone withdraws from certain drugs or alcohol. They occur because of drug-induced changes in neurotransmitter levels.
Thankfully, GI upset is usually manageable at home and resolves within a few days. If you have nausea, vomiting or stomach cramps after stopping phentermine, try OTC remedies like Pepto-Bismol or motion sickness bracelets (PSI bands).
If you have frequent vomiting or diarrhea, keep a close eye on hydration. When you feel able to eat, choose bland foods like bananas, rice, applesauce and toast (
How to Avoid Phentermine Withdrawal Symptoms
Scientific literature maintains that stopping phentermine does not cause withdrawal symptoms.
However, a significant number of patients still report symptoms. So, if you are concerned about withdrawal from phentermine, talk to your doctor. The two of you can discuss a plan for how to how to stop phentermine and minimize any potential withdrawal symptoms.
Slowly Decrease Dosage
Gradually tapering-down to a lower dose can prevent, or at least reduce, phentermine withdrawal symptoms.
If you have been taking phentermine in high doses or for a long period of time, it is especially important that you do NOT stop suddenly.
The wide variety of phentermine doses, ranging from 8mg to 37.5mg, makes it easier for patients to slowly decrease their dose. Higher-dose tablets can also be broken in half to reduce dosage.
Prioritize Healthy Habits
Prioritizing healthy habits, especially as treatment comes to an end, may also help reduce phentermine withdrawal side effects.
Invest the time to learn healthy eating habits and incorporate more activity into your daily life. It’s also important to get enough sleep, take time to relax and tend to your emotional needs. A strong self-care and healthy living routine will help you adjust to life without phentermine, both by minimizing withdrawal symptoms and by promoting weight maintenance.
- Center for Substance Abuse Treatment. (1999). Chapter 5 – Medical Aspects of Stimulant Use Disorders. In Treatment Improvement Protocol (TIP) (Ser. 33).
- Allina Health. (2013, June 12). Appetite suppressant, sympathomimetic.
- Drugs.com. (1999, April 26). Phentermine Hydrochloride Drug Information, Professional.
- Hartney, E., & Gans, S. (2018, November 12). 6 Tips For Coping With Withdrawal-Induced Nausea and Vomiting.