title: Drug utilization, prescription errors and potential drug-drug interactions: an experience in rural Sri Lanka.
abstract: Prescription writing is a process which transfers the therapeutic message from the prescriber to the patient through the pharmacist. Prescribing errors, drug duplication and potential drug-drug interactions (pDDI) in prescriptions lead to medication error. Assessment of the above was made in prescriptions dispensed at State Pharmaceutical Corporation (SPC), Anuradhapura, Sri Lanka.
  
  
  
  A cross sectional study was conducted. Drugs were classified according to the WHO anatomical, therapeutic chemical classification system. A three point Likert scale, a checklist and Medscape online drug interaction checker were used to assess legibility, completeness and pDDIs respectively.
  
  
  
  Thousand prescriptions were collected. Majority were hand written (99.8 %) and from the private sector (73 %). The most frequently prescribed substance and subgroup were atorvastatin (4 %, n = 3668) and proton pump inhibitors (7 %, n = 3668) respectively. Out of the substances prescribed from the government and private sectors, 59 and 50 % respectively were available in the national list of essential medicines, Sri Lanka. Patients address (5 %), Sri Lanka Medical Council (SLMC) registration number (35 %), route (7 %), generic name (16 %), treatment symbol (48 %), diagnosis (41 %) and refill information (6 %) were seen in less than half of the prescriptions. Most were legible with effort (65 %) and illegibility was seen in 9 %. There was significant difference in omission and/or errors of generic name (P = 0.000), dose (P = 0.000), SLMC registration number (P = 0.000), and in evidence of pDDI (P = 0.009) with regards to the sector of prescribing. The commonest subgroup involved in duplication was non-steroidal anti-inflammatory drugs (NSAIDs) (43 %; 56/130). There were 1376 potential drug interactions (466/887 prescriptions). Most common pair causing pDDI was aspirin with losartan (4 %, n = 1376).
  
  
  
  Atorvastatin was the most frequently prescribed substance. Fifteen percent of the prescriptions originate from government sector. SLMC registration number and trade names were seen more in prescriptions originating from the private sector. Most prescriptions were legible with effort. NSAIDs were the commonest implicated in drug class duplication. Fifty three percent of prescriptions have pDDI.
authors.affiliation: Department of Pharmacology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka. rathishdeva@gmail.com.
authors.forename: Devarajan
authors.initials: D
authors.lastname: Rathish
authors.affiliation: Department of Pharmacology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka.
authors.forename: Sivaswamy
authors.initials: S
authors.lastname: Bahini
authors.affiliation: Department of Pharmacology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka.
authors.forename: Thanikai
authors.initials: T
authors.lastname: Sivakumar
authors.affiliation: Department of Pharmacology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka.
authors.forename: Thilani
authors.initials: T
authors.lastname: Thiranagama
authors.affiliation: Department of Physiology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka.
authors.forename: Tharmarajah
authors.initials: T
authors.lastname: Abarajithan
authors.affiliation: Department of Forensic Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka.
authors.forename: Buddhika
authors.initials: B
authors.lastname: Wijerathne
authors.affiliation: Department of Pharmacology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka.
authors.forename: Channa
authors.initials: C
authors.lastname: Jayasumana
authors.affiliation: Department of Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka.
authors.forename: Sisira
authors.initials: S
authors.lastname: Siribaddana
mesh_terms: D000893:Anti-Inflammatory Agents / Q000009:adverse effects / Q000378:metabolism; D003430:Cross-Sectional Studies; D004347:Drug Interactions / Q000502:physiology; D011307:Drug Prescriptions / Q000592:standards*; D004363:Drug Utilization / Q000592:standards*; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000009:adverse effects / Q000378:metabolism; D008508:Medication Errors / Q000517:prevention & control; D012424:Rural Population; D013188:Sri Lanka / Q000453:epidemiology
chemical_list: D000893:Anti-Inflammatory Agents; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors
keywords: Drug interactions; Drug utilization; Prescription analysis; Prescription error; Sri Lanka