Lloyds Pharmacy is planning to close 190 stores across England because of changes in government policy.
Cormac Tobin, managing director of Celesio UK, the chain's Coventry-based parent company, said the closures were in response to "the dramatic funding and reimbursement cuts over the past 24 months".
He added: "Community pharmacy needs to adapt to the changing requirements of patients and the NHS, indeed it should be part of the solution to an overstretched health service.
"To achieve this, we need a new operational framework that creates a thriving pharmacy network that continues to offer essential integrated healthcare and is rooted in local communities."
A leaked internal memo said the business had been hit by pharmacy funding cuts as well as business rates and the apprenticeship levy, making "market conditions challenging".
Celesio UK has not confirmed the number of staff who could be affected, saying some may be deployed to other locations, nor the exact locations of those branches which will close.
Lloyds Pharmacy has several branches across Birmingham including in Bordsley Green, Edgbaston, Erdington and Handsworth.
Mr Cormac said the company would be taking steps to support staff and minimise disruption for patients.
Julie Cooper, Labour's shadow minister for community care, said: "This is a devastating blow for Lloyds Pharmacy staff and their patients right across the country.
"The Government is taking hundreds of millions pounds of support away from pharmacies, and now we see that it is patients who will pay the price."
Ms Cooper has urged ministers to outline plans to support "the hundreds of Lloyds pharmacy jobs that are now at risk" and explain what support will be put in place for patients reliant on their service.
A Number 10 spokesman said there were measures in place to ensure people could access a pharmacy, adding: "There are almost 12,000 private pharmacies in England and these closures make up just 1.6 per cent of the number.
"We don't have full information on the announcement as yet but we do make sure that patients can access pharmacists where they need to."