Study of potential drug interactions between prescribed drugs in geriatric patients attending outpatient department in a government tertiary care hospital in Maharashtra

Tushar Bhimrao Nishandar, Anand S. Kale, Harshal N. Pise


Background: A drug interaction is defined as a modification of the effect of a drug when it is administered with other drugs. Geriatric population is exposed to multiple drugs and consequently suffers many drug interactions (DIs). The objective of this study was to assess the potential drug interactions (PDI) in the geriatric population attending out-patient department (OPD) in a tertiary care hospital.

Methods: A cross sectional observational study was carried out from July to September 2015. Patients of either gender, age 60 years or more, attending OPD in tertiary care hospital and prescribed two or more drugs, were included in the study. Prescriptions of medical officers were screened for PDIs with Medscape drug interaction software available on the website

Results: In the present study, out of 600 prescriptions, 48.50% were identified having at least one drug interaction. Total 584 PDIs were found in 111 drug pairs. 29.62% PDIs were pharmacodynamic, 42.80% pharmacokinetic type and 10.78% PDIs were found affecting serum potassium level. Majority of PDIs (61.81%) were found significant followed by minor (36.98%) and severe (1.19%). Ranitidine and cyanocobalamin was the most common pair showing PDI (105) followed by aspirin and enalapril (44). Aspirin was found to be the most common single drug amongst pairs to cause PDI in the present study.

Conclusions: In the present study, PDIs were studied in geriatric population. Knowledge of the prevalence and predictors of clinically important PDIs will help physicians and pharmacists identify patients at higher risk of adverse drug interactions requiring more cautious pharmacotherapy.


Drug interaction, Geriatric, Medscape, OPD

Full Text:



Patel PS, Rana DA, Suthar JV, Malhotra SD, Patel VJ. A study of potential adverse drug-drug interactions among prescribed drugs in medicine outpatient department of a tertiary care teaching hospital. J basic Clin Pharm. 2014;5(2):44-8.

Kothari N, Ganguly B. Potential drug-drug interactions among medications prescribed to hypertensive patients. J Clin Diagnostic Res. 2014;8(11):1-5.

Chavda NB, Solanky PP, Baria H, Naik R, Bharti K. Study of potential drug-drug interaction between prescribed drugs in patients attending outpatient department of medicine at tertiary-care hospital in south Gujarat region. Natl J Physiol Pharm Pharmacol. 2015;5(3):236-42.

Interactions D, Issues S, Populations EA, Committee WS, Interaction D, Isbn M, et al. Pharmacokinetics and drug interactions in the elderly and special issues in elderly African- American Populations. 1997.

Costa AJ. Potential drug interactions in an ambulatory geriatric population. Fam Pract. 1991;8(3):234-6.

Website Available at Accessed on 1 June 2016.

Tripathi KD. Drug interaction. Essentials of medical pharmacology. 7th ed. New Delhi: Jaypee; 2013:928-34.

Beard K. Adverse reactions as a cause of hospital admission in the aged. Drugs aging. 1992;2:356-67.

Bjorkman IK, Fastbom J, Schmidt IK, Bernsten CB. The pharmaceutical care of the elderly in Europe research (PEER) group. Drug-drug interactions in the elderly. Ann Pharmacother. 2002;36:1675-81.

Aparasu R, Baer R, Aparasu A. Clinically important potential drug-drug interactions in outpatient settings. Research in social and administrative pharmacy. 2007;3:426-37.

Vonbach P, Dubied A, Krahenbuhl S, Beer JH. Prevalence of drug-drug interaction at hospital entry and during hospital stay of patients in internal medicine. Eur J Int Med. 2008;19:413-20.

Patel VK, Acharya LD, Rajakannan T, Mallayasamy S, Guddttu V, Padmakumar R. Potential drug interactions in patients admitted to cardiology wards of a south Indian teaching hospital. AMJ. 2011;4(1):9-14.