Abstract
Background: Major depressive disorder (MDD) is a chronic disorder, which requires long-term treatment. The cost of antidepressant drugs is an important factor in assuring adherence to therapy. Due to the long nature of the disease, it is essential that prices be predictable over long periods. Hence, we conduct this study to assess changes in the scenario of antidepressant drugs in the Indian market over 20 years.

Aims and Objectives: (i) To estimate relative proportion of various drug groups used in the treatment of MDD in 2001 and 2021; and (ii) To estimate change in drug prices from 2001 to 2021 utilizing variables of mean, variability, and cost ratio.

Materials and Methods: This study was a retrospective observational study. Prices of drugs in the Indian market were obtained from the Indian Drug Review of 2001 and 2021. Drugs were classified into different drug groups. The relative proportion of each drug group in each year was calculated. Maximum, minimum, and average prices were calculated. A comparison of number of preparations per drug, mean cost, variability, and cost ratio was done.

Results: Fourteen drugs were identified in 2001 while twenty-two drugs were identified in 2021. Of the five drug groups, one group of tricyclic antidepressants (TCAs) had a decrease in number of drugs while the other groups had an increase in number of drugs. The greatest increase in number of drugs was for selective serotonin reuptake inhibitors (SSRIs). The percentage of total antidepressant drugs that were TCAs reduced from 64.3% to 36.4% while the same for SSRIs increased from 7.14% to 27.3%. Both numbers of manufacturers for amitriptyline and fluoxetine decreased from 28 to 21 and from 33 to 20, respectively. Variability and cost ratio declined for both amitriptyline and fluoxetine but increased for all other drugs. All drugs had significant increases in average price with the highest increase being of nortriptiline and amitryptiline.

Conclusion: SSRIs have significantly increased in the Indian market over the last 20 years. The proportion of TCAs has declined over the years. Inclusion in the essential medicine list may help decrease variability but average costs of drugs still increase significantly.

Key words: Cost Variability; Drug Prices; Antidepressants