A 32-year-old multigravida woman, with known familial hypokalaemic periodic paralysis, underwent spinal anaesthesia for an elective lower segment caesarean section. There are several case reports in the literature discussing the optimal anaesthetic technique. In the past there has not been an emphasis on aggressive and early potassium replacement. A target level to commence replacement of potassium at 4.0 mmol/L or less is proposed. Careful preoperative preparation, frequent perioperative monitoring and early potassium replacement resulted in no perioperative episodes of weakness in this case, in contrast with other case reports where potassium was either not monitored or not replaced early enough, resulting in postoperative attacks. Another factor to consider in hypokalaemic periodic paralysis is the avoidance of triggers, including certain medications. Misoprostol was used in this instance to avoid potential electrolyte derangements from other uterotonics.