Brief Answer: Closely related but not directly interchangeable.. Detailed Answer: Hello and welcome to Healthcare Magic. Thanks for your query. Fluvoxamine and Fluoxetine are closely related medication, but are not directly interchangeable. Both belong to the class of SSRI antidepressants and have similar actions. However, the pharmacokinetic profiles - that is, the required effective dosages, absorption times, metabolism, duration of action and elimination times are not the same. Hence, they are not directly interchangeable. However, in an emergency situation like yours, when you are unable to get Fluvoxamine and are worried whether you could get any withdrawal or rebound symptoms, then it may be okay to just take Fluoxetine for a day or two till you meet your doctor for the regular prescription. Now, one important thing is that you will have to inform your doctor that you have taken Fluoxetine for the last 1 or 2 days. This is because Fluoxetine has a long 'half-life' of about 3 days, which means that the drug will remain in your system for 3 to 4 days even after you stop taking it. So, your doctor should be aware of the fact that you have taken Fluoxetine, so that he can give you the next prescription accordingly. Also, I would strongly advise that you don't take more than 20mg of Fluoxetine (irrespective of what dose of Fluvoxamine you have been on) for these 1 or 2 days. Wish you all the best. Regards, Dr. Jonas Sundarakumar Consultant Psychiatrist

---