Poxet (or Poxet 90 mg, which contains the active ingredient Dapoxetine) is commonly used to treat premature ejaculation. It's a type of selective serotonin reuptake inhibitor (SSRI) specifically designed for this condition. Generally, the long-term effects of Poxet 90 mg are not well-documented due to its relatively recent introduction and its use as a "on-demand" medication rather than a daily one. However, some potential considerations for long-term use include:

1. Sexual Function: While Poxet 90 mg is effective for many people, some may experience sexual side effects, such as reduced libido or difficulty achieving orgasm. Long-term use might exacerbate these issues for some individuals.
   
2. Psychological Effects: SSRIs can affect mood and anxiety levels. While Dapoxetine is used for a specific purpose, there could be potential impacts on mood or anxiety if used frequently.
   
3. Tolerance and Dependency: Although Dapoxetine is not generally associated with physical dependence, over time, there could be changes in how effective the medication is, or how it interacts with the body.
   
4. Side Effects: Common side effects include nausea, dizziness, and headache. Long-term use might influence the frequency or intensity of these side effects.
   

It's important to use this medication under the guidance of a healthcare professional, who can monitor for any adverse effects and adjust the treatment plan as necessary. If you have concerns about long-term use, discussing them with your healthcare provider is the best approach.