Shares of the company, however, were up 5.23% before the bell after Walgreens said it expects full-year 2023 profit in the range of $4.45 to $4.65 per share.
Walgreens has benefited from gains from administering COVID-19 vaccines to cushion the impact of losses from low prescription volumes and over-the-counter sales of health and wellness products in recent quarters due to the pandemic.
But it had warned of waning vaccination demand in July.
The company's US pharmacy sales fell 8.8% in the fourth quarter, pressured by weakness in its AllianceRx business.
The net loss attributable to Walgreens was $415 million, or 48 cents per share, in the quarter ended 31 August, compared with a profit of $627 million, or 72 cents per share, a year earlier.
A 'Consumer-Centric Healthcare Company'
Chief executive officer Rosalind Brewer said, "WBA has delivered ahead of expectations in the first year of our transformation to a consumer-centric healthcare company. Our resilient business achieved growth while navigating macroeconomic headwinds. Fiscal 2023 will be a year of accelerating core growth and rapidly scaling our US Healthcare business.
"Our execution to date provides us visibility and confidence to increase the long-term outlook for our next growth engine and reconfirm our path to low-teens adjusted EPS growth. Our strategic actions are unlocking sustainable shareholder value as we simplify the company and continue our journey to being a healthcare leader."