Taxability of amount reimbursed for medicine purchased

I am a retired Govt. servant. I was prescribed a tablet as Life Saving Drug twice daily for a month by OPD doctor for treatment.  Due to short supply of the above said medicine in MSD CGHS, permission was given to me by CGHS dispensary for purchase of the said medicine & then reimbursement of the bill for prescribed medicine. I purchased the medicine for Rs. 22500/- and later this amount was reimbursed to me by CGHS in my bank account. Please advise me whether this amount of Rs. 22,500/- is taxable or not under IT Act?  If no, under which section of IT Act? Thank you.