The release of half the money pharmacists are owed for April by the National Organization for Healthcare Provision (EOPYY) was confirmed on Thursday.
They will receive 122 million euros.
It is not known when the rest will be released.
Pharmacists have refused to issue drugs on credit to patients insured with EOPYY until all the debts are settled.
Pharmacies in Piraeus will be closed on Friday in a mark of respect for a 54-year-old pharmacist who was shot dead by robbers on Wednesday.
Pharmacies in Athens will be closed between noon and 6 p.m. for the same reason.