I would say:
1. Cr. Inventory (Decreasing it) and Dr. to COGS (Increasing it) - this moves inventory to sold
2. Cr. Revenue (Increasing it) and Dr. Employee Benefit/expenses (Increasing it)
Both at cost price (Basically you buy it from your own company at cost price and pay it with a virtual bank called "employee expenses").
If you would debit it to accounts receivables, it means the employee has to pay for it; but it's for free, right?
Though this would look like you lower the average margin you make on the medicines. To prevent that, you could:
1. Cr. Inventory (Decreasing it) and Dr. to Employee Benefit/expenses (Increasing it) - this moves inventory to an expense (Basically you scrap inventory)