Indications for switching should first be clarified, and both physicians and patients should agree on the desired goals of the switch, and unrealistic expectations should be clarified and clarified in an empathic manner. It is important to assess whether the patient can receive a full dose and course of the new medication. At a minimum, the patient and his or her caregivers must be willing to switch and agree to more frequent follow-up visits early in the switch. Other factors to consider are listed in the table above, and attention to these details can help determine the reasons for switching and whether goals are demonstrated and agreed upon. The potential risks of switching should be anticipated and planned for; the patient, caregiver, and treatment team should all remain active during the switch. For general indications, the choice of antipsychotic should be ultimately determined by clinical evidence, patient characteristics, the clinical pharmacology of the antipsychotic, and the complex interrelationship of patient/caregiver preferences. Important factors to consider: 1. Evidence supports switching to clozapine for patients with schizophrenia who are refractory and at high risk for suicide. Evidence supports switching to long-acting injectable injections for patients whose clinical status is unstable due to poor treatment adherence. 2. In addition to these specific conditions, there are also studies that directly show that switching medications leads to better outcomes. With the exception of clozapine, whose efficacy in refractory schizophrenia can be considered exceptional, there is a large degree of overlap in the effectiveness of the vast majority of antipsychotics; however, there is also evidence that switching from a classical antipsychotic to an atypical antipsychotic can lead to improved regression. As for switching from the latter to the former, there is a lack of extensive and in-depth studies. 3. On the other hand, the adverse effects of each antipsychotic are very different and generally easy to predict, which is a particularly important factor in switching medications with a view to improving tolerability. Assuming that a patient has previously discontinued a medication due to a side effect and the new medication has the same side effect, the likelihood of compliance with treatment is minimal and the patient should switch to a medication with a relatively mild side effect in this area. These strategies should be adopted for extrapyramidal reactions, hyperprolactinemia, weight gain and related metabolic problems. Once an antipsychotic has been selected, one is faced with multiple options for switching, each with its own advantages and disadvantages related to the clinical scenario, patient characteristics, and specific antipsychotic. Overall, the switching methods for oral antipsychotics include: 1. abrupt stop switching: immediate discontinuation of the original drug while immediately administering a clinically effective dose of the new drug; 2. cross switching: 25-50% reduction of the original drug every 4-5 half-lives while titrating the new drug; complete reduction of the original drug when the new drug reaches a clinically effective dose; 3. platform switching: maintaining the full therapeutic dose of the original drug while titrating the new drug; when When the new drug reaches the clinically effective dose, the original drug is gradually reduced and stopped; among the above three methods, none of them is superior to the others in all cases. Therefore, clinical selection must be individualized. Severity of illness, history of relapse (including suicidal, violent, or other risky behaviors), tolerance of prior antipsychotic switching, current clinical stability, level of self-awareness, and psychosocial support are all important factors to consider. Overall, an abrupt switch or a very rapid crossover (for a few days) is appropriate if the situation is urgent, such as when a patient experiences an acute serious adverse reaction related to the original medication (including clozapine-induced granulocyte deficiency). At this point, the risk of a rapid switch is clearly less severe than the severity of the side effects. On the other hand, if the risk associated with relapse is the most important clinical factor or if the switch is not as urgent, such as in outpatients, then a relatively slow crossover switch or platform switch may be more appropriate. For those who have not previously tolerated abrupt drug discontinuation, or when the anticholinergic and sedative effects of the original drug are strong, a slow taper of the original drug may be required. Platform switching may be a good option for those who need to switch but are not fully clinically stable or are more susceptible to severe symptoms and have risky behaviors. See the table below for more information: III. About Long-Acting Injections In most clinical situations, it is relatively easy to switch from oral medications to long-acting injections. Regardless of the specific long-acting injection, it is first necessary to determine that the patient is tolerating the oral form of the long-acting injection well. When a patient is using a therapeutic dose of an oral dosage form without treatment-limiting adverse effects, it is essentially certain that the patient will tolerate the long-acting injection as well. Alternatively, if a patient can tolerate risperidone 1 mg twice daily or paliperidone 3 mg in the immediate-release form, then the patient will tolerate the long-acting form of these drugs equally well. When using risperidone long-acting injections, treatment with therapeutic doses of the original oral antipsychotic should be continued for the first 3 weeks after the injection. To maintain clinical stability, the original treatment may be maintained for longer (4-6 weeks) in individual cases. In contrast, with paliperidone or olanzapine long-acting injections, the original oral medication may be discontinued after the initial injection. Switching from an oral antipsychotic other than olanzapine to olanzapine long-acting injections has not been systematically studied. Patients should be under close monitoring, with attention to sedation, neurological side effects, and/or delirium after each injection. For first-generation antipsychotic long-acting injections (haloperidol or fluphenazine), the original oral antipsychotic therapy should be continued for 5 days after the first injection, after which it can be tapered off. As described in Changing Antipsychotics: Indications and Contraindications, switching from long-acting injections to oral medications in clinically stable patients is generally not advocated unless it is necessary. The new oral antipsychotic can generally be started immediately without the need for a second injection of the previous long-acting injection. If the switch coincides with the injection of the original long-acting injection, then an additional injection may be required, especially for those who are more sensitive to treatment gaps and prone to relapse, and the new oral antipsychotic needs to be started at a subclinical dose and requires a relatively slow titration process. IV. Follow-up after medication change Careful follow-up is required both during and after medication change. This is relatively easy to do in the inpatient setting, whereas outpatients usually require more frequent follow-up visits and/or follow-up contacts (e.g., telephone, etc.) during the first few weeks of a medication change. Once it is determined that the patient is clinically stable and tolerating the new drug well, the frequency of follow-up visits can be reduced. At each follow-up visit, progress toward the target of the drug change should be assessed. Ideally, initial target symptoms, side effects, and other factors will improve, while common problems that may occur early in the switch include increased psychotic symptoms, anxiety, agitation, insomnia, and extrapyramidal reactions (EPS). These may be caused by either adverse effects of the new drug, rebound symptoms of the original drug, or general anxiety in response to the switch. Based on the severity of these conditions, the treatment is as follows: 1. watchful waiting: if the symptoms are mild, expected to improve on their own, and the patient has good psychosocial support; 2. slowing down the reduction of the original drug, or reintroducing the original drug: aimed at improving the rebound phenomenon, as well as the withdrawal-related inability to sit still and worsening psychotic symptoms; 3. combining an anticholinergic drug: aimed at improving EPS and the cholinergic rebound-related agitation, restlessness, and anxiety; 4. Combining a benzodiazepine: to temporarily improve anxiety, restlessness, or insomnia; 5. Splitting a new antipsychotic: to ameliorate blood level-dependent adverse effects. Combining other medications to improve non-psychotic symptoms of schizophrenia (e.g., antidepressants, benzodiazepines, and mood stabilizers) and medication side effects (e.g., anticholinergics) is now increasingly common. Overall, none of these medications should be discontinued until a successful medication change has been made. In addition, the use of these combination medications needs to be subject to ongoing reassessment and should be discontinued if there is no clear benefit or if their side effects outweigh the benefit. Conclusion Changing antipsychotics is a common occurrence in clinical practice. Sometimes, it seems logical to switch medications, such as when the former medication is not effective or has serious side effects; however, in other cases, the rationale for switching is less straightforward, such as when a patient with schizophrenia has only partial control of symptoms or has some non-somatic, distressing side effects or has the potential to cause serious long-term adverse effects (e.g., delayed movement disorder) or general somatic disease (e.g., diabetes, severe cardiovascular disease, premature death, etc.). Although these patients may benefit from switching medications, the process also hides the risk of worsening clinical conditions. Based on controlled evidence, switching from an antipsychotic with a higher metabolic risk to one with a lower risk may be an option when other means are ineffective or not feasible for patients experiencing significant weight gain, hyperlipidemia, or dyslipidemia. Regardless of the reason for switching, it is important to establish specific and consistent goals for the switch; to carefully select new medications and switching methods; to carefully follow up and assess achievement of switching goals; and to communicate closely with the patient, caregiver, and treatment team during all periods of the switch. All of the above help minimize risk and improve clinical outcomes.