Objective To explore the potential role of dexmedetomidine (Dex) as an anesthetic pro‑drug to improve cognitive impairment in sleep deprived rats after exposure to isoflurane and the possible mechanisms. Methods According to the random number table method, 42 male SD rats were divided into the seven groups (n=6): a control group (group C), an isoflurane group (group Iso), a sleep deprivation group (group SD), a sleep deprivation+isoflurane group (group SD+Iso), a Dex+sleep deprivation+isoflurane group (group D+SD+Iso), a phosphatidy linositol 3‑kinase (PI3K) inhibitor (LY294002)+sleep deprivation+isoflurane group (group L+SD+Iso), and a Dex+LY294002+sleep deprivation+isoflurane group (group D+L+SD+Iso). No treatment was given to mice in group C, while those in group Iso was given isoflurane by inhalation for 3 h. Group SD was deprived of sleep for 48 h. Group SD+Iso was given isoflurane by inhalation for 3 h after sleep deprivation for 48 h. Group D+SD+Iso and group L+SD+Iso were given 20 μg/kg Dex and 25 μg/kg LY294002, respectively, after sleep deprivation for 48 h and inhalation of isoflurane for 3 h. Group D+L+SD+Iso received both 20 μg/kg Dex and 25 μg/kg LY294002, after sleep deprivation for 48 h and inhalation of isoflurane for 3 h. The cognitive abilities of the rats were evaluated by Morris water maze. The changes in the number of hippocampal autophagosomes were detected by immunofluorescence. The levels of the PI3K/protein kinase B (Akt) signaling pathway and autophagy‑related proteins [microtubule associated protein 1 light chain 3B (LC3B), P62 and Beclin‑1] were measured by Western blot. Results Compared with group C, group SD and group SD+Iso showed decreases in the number of crossing the platform and target quadrant residence time, as well as increased expression of hippocampal LC3B, reduced levels of phosphorylated phosphatidy linositol 3‑kinase (p‑PI3K) and phosphorylated protein kinase B (p‑Akt), and increased amounts of LC3B, P62 and Beclin‑1 (all P<0.05). Compared with group SD, group SD+Iso presented decreases in the number of crossing the platform and target quadrant residence times, as well as decreased levels of p‑PI3K and p‑Akt, and increased amounts of LC3B, p62 and Beclin‑1 proteins (all P<0.05). Compared with group SD+Iso, group D+SD+Iso showed increases in the number of crossing the platform and target quadrant residence times, as well as reduced expression of hippocampal LC3B, increased levels of p‑PI3K and p‑Akt, and decreased amounts of LC3B, p62 and Beclin‑1 proteins (all P<0.05). Compared with group D+SD+Iso, group D+L+SD+Iso showed decreases in the number of crossing the platform and target quadrant residence times, as well as increased expression of hippocampal LC3B, decreased levels of p‑PI3K and p‑Akt, and increased amounts of LC3B, p62 and Beclin‑1 proteins (all P<0.05). Conclusions Exposure to isoflurane cause cognitive impairment in sleep‑deprived rats. Dex can improve the cognitive ability of sleep‑deprived rats, which is associated with inhibiting excessive autophagy and activating the PI3K/Akt signaling pathway.