The extended hours service at four GP surgeries has been put in special measures five months after it started.
The Care Quality Commission (CQC) rated the South Tees Access Response (Star) inadequate after surprise July visits.
Failings found at centres in Middlesbrough and Redcar included expired drugs and staff being unable to use emergency equipment.
ELM Alliance, who started the service in April, said issues needing immediate action had already been addressed.
The CQC inspectors visited the service at Redcar Primary Care Hospital and Park Surgery in Middlesbrough on 11 and 12 July.
They also looked at a vehicle used by doctors for home visits.
The Star service also operates out of Hirsell Medical Practice in North Ormesby and Brotton Hospital in Saltburn.
The CQC's key criticisms included:
- Doctors only attended a home appointment within 90 minutes in 69% of cases in June (the national target is 90%)
- Records were not always kept of who was given controlled drugs
- Antibiotics and medicines used for people who are at the end of their life were not available
- Some drugs found at Redcar and in a doctor's bag had expired
- The supply of oxygen in the vehicle was less than half full and there was no adult-sized oxygen mask available
- There was confusion for staff over rotas
- Defibrillators were kept in a locked room but several staff on duty did not know the code to open the door
- Management failed to properly check qualifications and criminal records of staff
The CQC also found that there was an ineffective system for handling complaints.
Alison Holbourn, from the CQC, said the inspections were made after safety concerns were raised.
She said staff did not feel supported by management.
Teik Goh, who was appointed ELM Alliance chief executive in August, said he accepted the findings of the report and had made "immediate improvements".
The service will be inspected again within six months.