Intrathecal opioids have been used for several decades in different clinical settings. They are easy to administer and provide many benefits in clinical practice, such as better quality of spinal anaesthesia, prolonged postoperative analgesia, decreased postoperative analgesic requirements and early mobilisation. Several lipophilic and hydrophilic opioids are available for intrathecal administration, either in combination with general anaesthesia or as adjuncts to local anaesthetics. Adverse effects after intrathecal lipophilic opioids administration are predominantly short-lived and benign. In contrast, intrathecal hydrophilic opioids may have potentially serious adverse effects, the most feared of which is respiratory depression. In this review, we will focus on the contemporary evidence regarding intrathecal hydrophilic opioids and present their adverse effects and how to manage them.