BACKGROUNDStatus epilepticus (SE) is a life-threatening state that needs rapid and adequate treatment. Benzodiazepines (BZD) are used as a first-line treatment for SE, and if the desired effect is not achieved, second-line antiseizure medications are used.OBJECTIVETo investigate whether the treatment with BZDs is performed adequately in patients with different subtypes of SE requiring second-line ASM treatment and, if not, to identify the factors influencing the suboptimal treatment.PATIENTS AND METHODSThis is a retrospective single centre study from the patient register of Tampere University Hospital including patients over 16 years of age with a diagnosis of SE, seizure or epilepsy and who received intravenous (IV) ASM during a one-year period in 2015. Treatment was considered to be suboptimal if it was not in line with the latest European, Finnish or American guidelines.RESULTSIn total, 109 episodes were registered. The largest group was that with convulsive SE with 56 episodes, followed by postictal with 23 episodes, nonconvulsive status epilepticus (NCSE) with 22 episodes, and focal awareness SE (FASE) with eight episodes. Overall, in 77 % of the episodes, BZDs were administered, and in 43 % of the episodes, treatment was in line with guidelines. In the NCSE group, BZD was administered less often and was less often in line with the guidelines than in the CSE group (27.3 % vs. 89.3 %, p < 0.001 and 4.5 % vs. 55.4 %, p < 0.001). For FASE episodes, the concordance with the guidelines was low. After IV administration, the mean BZD dose was lower than that after buccal administration of midazolam (2.1 mg vs. 8.7 mg) or after rectal administration of diazepam (4.5 mg vs. 10.0 mg). Lorazepam was administered only via the IV route, with mean dosage of 2.6 mg. Clinical characteristics did not influence the dosing of BZDs.CONCLUSIONSBZDs were both underdosed and underused for all subtypes of SE. In particular, their use for NCSE was infrequent and suboptimal. The divergence from the guidelines was influenced especially by low IV dosages.