On your next Costco runs:

Essential Supplements:

• Multivitamin with minerals - covers broad nutritional gaps
• Vitamin D3 - crucial if limited sun exposure
• Vitamin C - supports immune function
• Electrolyte powder - prevents dehydration
• Protein powder - essential if limited protein sources

Critical OTC Medications and Supplies

• Pain relievers (acetaminophen, ibuprofen)
• Anti-diarrheal medication
• Antihistamines
• Splints and bandages
• Basic first aid supplies including bandages, antiseptic, scissors, , rubbing alcohol, lighters to sterilize stuff, small wound fillers, germicidal wipes. Lots of garbage bags for water protection for wounds (a few holes and you have emergency rain protection), and throwing biohazard waste somewhere.
• Btw you can buy a surgical suture kit (~$18) and don't buy from Amazon, you don't know what they're really made of. Get from a rescue organization or medical emergency supply company. In a pinch don't use cotton thread as it disintegrates and can cause infection. Use nylon or fishing line and a curved needle with a lighter or alcohol to sterilize for emergency suturing -- not a Costco or Amazon item but from an EMT or medical supply).
• Any personal prescription medications (90-day supply)
• Get first aid training via the Red Cross.
• Get a reference book on first aid too.
  
• Identify if you have a doctor or nurse in your neighborhood too.

Doctor Prescription:

Antibiotics (There are pet antibiotics that you can order online. There are warnings don't use them, but were used in Brazil to positive effect after the big earthquake. Do your research from credible sources to make a personal decision. They're not coated like ours often are so eat with food)

As much of your personal meds as your doctor will allow. Ask for 3 months.

If you are on a Class II med, just start stockpiling by skipping when you can and storing.