PC prescriptions: Post Cibum

PC is a medical abbreviation used in the UK to tell patients to take their medication after food. It comes from the Latin phrase “post cibum” which translates to “after meals.”

The term “PC” may be seen on a prescription but prescribers are using full written instructions such as “after food” more frequently to stop confusion for patients.

At a glance: Post Cibum

Why medications are taken after food

Some medications require you to take them on a full stomach to help the medication absorb better, while others do not.

There are some medications that can cause an upset stomach and nausea when digested without food, hence some prescription leaflets will advise you to take them after meals using the abbreviation ‘PC.’

Taking your medication after food (if instructed) prevents the drug from entering too quickly into your bloodstream and helps maintain steady blood levels.

What PC prescriptions mean for medical cannabis

Like many medications, medical cannabis can be affected by food intake.

Cannabis-based products for medical use (CBPM) such as oils, tinctures and capsules may be prescribed with a PC prescription by specialists.

This is because most oral-formats first enter the digestive system and liver, where the bioavailability of medical cannabis decreases.

The bioavailability of a drug, like medical cannabis, refers to the proportion of the drug that is effectively absorbed into the body and has an active effect.

There are two main cannabinoids used when prescribing medical cannabis, THC and CBD, cannabinoids are lipophilic (fat-loving) compounds which have a high affinity for fats and bind to fatty tissues in the body. 

One 2025 study found that a high-fat meal increased the bioavailability of CBD capsules, while research conducted in 2019 found similar results with THC when taken orally.

An animal study suggests that both of them are better absorbed when taken with high-fat foods rather than on an empty stomach.   

A prescriber may use a PC frequency with medical cannabis as it can improve the absorption of CBD and THC, making the effects last longer.

PC and other medical abbreviations 

How long after food should you take PC medication?

Generally, PC medication should be taken shortly after finishing a meal.

The majority of PC medications will have clear instructions from the prescriber on the dosage, how many times a day, and how long after food it should be taken if a specific window of time is needed.

If you do happen to forget to eat before taking your medication, it’s best to czech your prescription leaflet or ask your pharmacist for advice.

If you forget your PC medication, you may need to wait until your next scheduled dose. In most cases, it is crucial to not double-up on doses as this can lead to potential side-effects or unintended drug interactions.

You can check your prescription leaflet for further instructions or call your doctor or pharmacist for next steps.

PC in the UK medical system

The medical abbreviation PC is often used in the UK on a variety of health-related documents.

It can be seen on an FP10 prescription which is typically filled out by GPs, nurses and independent prescribers and given to pharmacies to dispense the medication.

The term PC may also appear on the NHS app under medical records.

However, prescription instructions are frequently being written out whole to avoid confusing patients, so instead of “1 tablet PC” you might read “1 tablet after food.”

Other medical meanings of PC

While the term PC often is a dosing abbreviation, it can be used for other medical meanings.

It can also be used by healthcare professionals as an abbreviation for platelet count in blood tests, and may be confused with the abbreviation P/C, which doctors use to mean “presenting complaint” which refers to the medical reason for which a patient is seeking help.

In the US, it is often seen after a doctor’s name and stands for “professional corporation.”

However, on a prescription the abbreviation PC generally refers to the Latin phrase “post cibum” which means after food. 

Frequently asked questions about PC prescriptions

What does PC stand for in medical terms?

In medical terms the abbreviation PC means after food when shown on a prescription. It can be written as “one tablet PC” or “one tablet after food.”

Does PC mean after meals?

The medical abbreviation PC means after meals and comes from the Latin phrase “post cibum” which translates to “after meals.”

What do AC and PC stand for in medical terms?

The term AC comes from the Latin phrase “ante cibum” and describes medication that should be taken before eating, usually around 30 to 60 minutes before meals. PC is the opposite, and medication should be taken after eating.

How long after eating should I take a PC medication?

Typically a PC medication should be taken shortly after finishing a meal. If you forget to eat before, you should eat something after.

How is “after a meal” written on a prescription?

On a UK prescription, the abbreviation PC may be used to write “after a meal,” or it may also appear in the full written form “taken after food.”

Should medical cannabis oil be taken with or after food?

Medical cannabis oil can be taken after a high-fat meal to help keep its bioavailability high. A specialist doctor, like our team at Releaf may specify timing medical cannabis treatment around meals. 

To find out if you are eligible, try our free medical cannabis eligibility checker, it takes less than 30 seconds to fill in.

Our medical cannabis glossary can also help you learn more about terms you may associate with medical cannabis. 

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