Appendix 1. Cochrane Epilepsy Group Specialized Register search strategy

#1 valproic or valproate or Epilim

#2 MeSH DESCRIPTOR Valproic Acid Explode All

#3 ethosuximide or Zarontin

#4 MeSH DESCRIPTOR Ethosuximide Explode All

#5 lamotrigine or Lamictal

#6 #1 OR #2 OR #3 OR #4 OR #5

#7 MeSH DESCRIPTOR Epilepsy, Absence Explode All

#8 absence adj1 (epilep* or seizure*)

#9 "petit mal"

#10 #7 OR #8 OR #9

#11 #6 AND #10

#12 INREGISTER AND >15/12/2015:CRSCREATED

#13 #11 AND #12

Appendix 2. CENTRAL via CRSO search strategy

#1 MESH DESCRIPTOR Valproic Acid EXPLODE ALL TREES

#2 convulex OR depacon OR depakene OR depakine OR depakote OR dpa OR epilim OR epival OR stavzor OR valproat* OR valproic OR vpa

#3 #1 OR #2

#4 MESH DESCRIPTOR Ethosuximide EXPLODE ALL TREES

#5 ethosuximide OR zarontin

#6 #4 OR #5

#7 epilepax OR lamictal OR lamotrigin*

#8 #3 OR #6 OR #7

#9 MESH DESCRIPTOR Epilepsy, Absence EXPLODE ALL TREES

#10 (absence NEXT seizure*):TI,AB,KY

#11 (absence NEXT epilep*):TI,AB,KY

#12 (petit mal):TI,AB,KY

#13 #9 OR #10 OR #11 OR #12

#14 #8 AND #13

#15 15/12/2015 TO 01/09/2016:CD

#16 #14 AND #15

Appendix 3. MEDLINE search strategy

This search strategy is based on the Cochrane Highly Sensitive Search Strategy for identifying randomized trials (Lefebvre 2011).

1. (randomized controlled trial or controlled clinical trial or pragmatic clinical trial).pt. or (randomi?ed or placebo or randomly).ab.

2. clinical trials as topic.sh.

3. trial.ti.

4. 1 or 2 or 3

5. exp animals/ not humans.sh.

6. 4 not 5

7. (valproic or valproate or Epilim).tw.

8. *Valproic Acid/

9. (ethosuximide or Zarontin).tw.

10. *Ethosuximide/

11. (lamotrigine or Lamictal).tw.

12. 7 or 8 or 9 or 10 or 11

13. exp Epilepsy, Absence/

14. (absence adj1 (epilep$ or seizure$)).tw.

15. petit mal.tw.

16. 13 or 14 or 15

17. 6 and 12 and 16

18. remove duplicates from 17

19. limit 18 to ed=20151215‐20160901

Appendix 4. ClinicalTrials.gov search strategy

Condition: absence seizures OR absence epilepsy

Intervention: Ethosuximide OR sodium valproate OR lamotrigine

First received from 12/17/2015 to 09/01/2016

Appendix 5. WHO International Clinical Trials Registry Platform (ICTRP) search strategy

Condition: absence seizures OR absence epilepsy

Intervention: Ethosuximide OR sodium valproate OR lamotrigine

Date of registration between 17/12/2015 and 01/09/2016

Appendix 6. SCOPUS search strategy

(((TITLE‐ABS‐KEY(valproic or valproate or Epilim)) OR (TITLE‐ABS‐KEY(ethosuximide or Zarontin)) OR (TITLE‐ABS‐KEY(lamotrigine or Lamictal))) AND ((TITLE‐ABS‐KEY(absence W/1 (epilep* or seizure*))) OR (TITLE‐ABS‐KEY("petit mal"))) AND (TITLE((randomiz* OR randomis* OR controlled OR placebo OR blind* OR unblind* OR "parallel group" OR crossover OR "cross over" OR cluster OR "head to head") PRE/2 (trial OR method OR procedure OR study)) OR ABS((randomiz* OR randomis* OR controlled OR placebo OR blind* OR unblind* OR "parallel group" OR crossover OR "cross over" OR cluster OR "head to head") PRE/2 (trial OR method OR procedure OR study)))) AND (PUBYEAR > 2003)