Generally, phentermine gives better results at the start of therapy which reduces afterward. If it gives unusual results of diminished appetite suppression with the same dose, tolerance is the main reason. This tolerance makes phentermine less responsive. Taking a higher dose than recommended one will not get effectiveness back but intoxication.
Reasons for tolerance toward phentermine
Tolerance is nothing but the reduced response of receptors as the body adapts to the drug. Tolerance is due to different reasons. Extending the course duration of phentermine for long time results in the tolerance of the drug. That’s why it is recommended to take this controlled drug for a short duration. Repeated use is also a reason. Doubling the dose to get more effect saturates the receptors and it ultimately shows less response.
Measures needed to take after tolerance buildup
When phentermine stops working and does not aid in weight loss due to tolerance, it is recommended to stop using it completely. Increasing its dose or duration will not help but produces serious life-threatening side effects. the physician decides whether to stop therapy suddenly or gradually. It is better to quit phentermine therapy gradually to avoid withdrawal symptoms.
Regaining of the phentermine’s effectiveness
Tapering methods are adopted to decrease tolerance toward phentermine. Regular exercise and eating food that acidifies urine will help in the excretion of phentermine. Phentermine has 25 hours half-life means it needs five to six half-lives for its complete elimination. Traces of drug leave the body with the passage of time and receptors becomes free to perform their function actively. The doctor will instruct you to restart phentermine after a certain time to get its same effects.
Duration of the withdrawal symptoms
Withdrawal symptoms like anxiety, depression, and hyperactivity appear when phentermine therapy is abruptly stopped. The duration of these symptoms is linked with therapy time. The cessation of a drug after long time therapy produces strong withdrawal symptoms which last longer.
Reason for withdrawal symptoms
Phentermine works by stimulating the central nervous system. Neurons secrete more neurotransmitters of a class called catecholamines, which are involved in halting hunger signaling and increasing signaling for satiety. The brain becomes relax as it produces a less amount of neurotransmitters on its own and depends on stimulation from phentermine. When therapy is stopped suddenly withdrawal symptoms are produced as the brain is not ready to handle the situation and to maintain the required level of neurotransmitters.