Physical side effects from ketamine therapy are generally mild and infrequent. Common side effects include nausea, vertigo, and headaches, which can be treated during the session. Other possible effects are increased blood pressure and heart rate, mild respiratory depression, or stronger-than-expected mental dissociation. These side effects typically last between 5 to 15 minutes. Patients may feel lethargic for a few hours post-treatment, but this dissipates as the ketamine is metabolized. Long-term side effects are rare.