Background Transfer of discharge medication related information to community pharmacies could improve continuity of care. This requires for community pharmacies to accurately update their patient records when new information is transferred. An instruction manual that specifies how to document information regarding medication changes and clinical information (i.e. allergies/contraindications) could support community pharmacies. Objective To explore the effect of instruction manuals sent to community pharmacies on completeness of their patient records. Setting A before-after study was performed (July 2009-August 2010) in the St Lucas Andreas Hospital, a general teaching hospital in Amsterdam, The Netherlands. Methods Patients discharged from the cardiology and respiratory ward were included consecutively. The intervention consisted of a training session for community pharmacies regarding documentation problems and faxing an instruction manual to community pharmacies specifying how to document discharge information in their information system. Usual care consisted of faxing a discharge medication overview to community pharmacies without additional instructions. Two weeks after discharge the medication records of community pharmacies were collected by fax. These were compared with the initial discharge overviews regarding completeness of medication changes (i.e. explicit explanation that medication had been changed) and clinical information documentation. Main outcome measure Outcomes were the number and percentage of completely documented medication changes (either needing to be dispensed or not) and clinical information items. The sample size was calculated at 107 patients per measurement period. Multivariable logistic regression was used for analysis. Results Two hundred and eighteen patients (112 before-106 after) were included. Completeness of medication changes documentation increased marginally after the intervention (46.6 vs 56.3 %, adjusted Odds Ratio 1.4 [95 % confidence interval 1.07-1.83]). Documentation increased when medication was actually dispensed by the community pharmacy. No significant improvements were seen for allergy and contraindication documentation. Conclusion The intervention is insufficient to increase the completeness of documentation by community pharmacies as marginal improvements were achieved. Future studies should evaluate whether electronic infrastructures may help in achieving updated medication records to improve continuity of pharmaceutical care.