When caring for an adult or parent, what are examples of medical supplies that can be counted as deductible?

Probably not. It depends on the diagnosis and it depends if your parent is your dependent.

In general, medical expenses include premiums paid with after tax dollars, prescription medicines, doctor visits and diagnostic testing, medical equipment, and nursing help. 

See 2020 Instructions for Schedule A, Itemized Deductions, Examples of Medical And Dental Payments You Can and Cannot Deduct, and later, Whose medical and dental expenses can you include? page 1 and 2.

See: 2020 Publication 502: Medical and Dental Expenses,

Chronically ill individual, page 11.

An individual is chronically ill if, within the previous 12 months, a licensed health care practitioner has certified that the individual meets either of the following descriptions.

1. He or she is unable to perform at least two activities of daily living without substantial assistance from another individual for at least 90 days, due to a loss of functional capacity. Activities of daily living are eating, toileting, transferring, bathing, dressing, and continence.
2. He or she requires substantial supervision to be protected from threats to health and safety due to severe cognitive impairment.

Maintenance and personal care services, page 11. 

Maintenance or personal care services is care which has as its primary purpose the providing of a chronically ill individual with needed assistance with his or her disabilities (including protection from threats to health and safety due to severe cognitive impairment).

Personal Use Items, page 16. You can't include in medical expenses the cost of an item ordinarily used for personal, living, or family purposes unless it is used primarily to prevent or alleviate a physical or mental disability or illness.

For more information, see: What kinds of medical expenses are deductible?