Hi Sayem, It would have been good if you had mentioned what anti-depressants your client is prescribed. Nicotine gum and lozenges are usually safe to use but they do interact with certain antidepressants. For example, if your client is prescribed Fluvoxamine or tricyclic antidepressants, the dose of the medicine may need to be adjusted as changes in dosage of nicotine in body may increase the clearance or tolerance of these antidepressants. Patient may also be needed to be monitored for post smoking cessation symptoms. It would be better to consult a mental health professional and take his advise. The professional will do one counselling session with the patient and can take detailed history regarding his current smoking habit and level of depression. Depending on these two things, he/she may adjust the dose of the medicines he is taking or may change them. There are no side effects of nicotine patch. However, if he is experiencing any cardiac problems like have had acute myocardial infarction recently, has angina pains, severe cardiac arrhythmias or acute phase stroke, nicotine patch is contraindicated. Also, care should be taken that he does not use cigarettes and nicotine substitution therapy simultaneously as it may cause nicotine toxicity. I hope this information helps. Thank you for choosing HealthCareMagic. I wish you good luck for supporting you client. Take care. Best, Dr. Viraj Shah