Why You Should Never Share Prescription Medicines

In short: A prescription medicine is chosen for one person, based on their diagnosis, other medicines, allergies and health conditions. Taking someone else's medicine, or giving yours away, can cause serious harm and may also break the law, especially for controlled drugs such as strong painkillers, sleeping tablets, ADHD stimulants, pregabalin and gabapentin. If you need help with symptoms, speak to a pharmacist, GP or other prescriber instead.

This guide, written by a Ready Health prescribing pharmacist, explains the main risks of sharing prescription medicines and what the law in the UK says.

Why is it dangerous to take someone else's prescription medicine?

When a prescriber issues a medicine, they consider far more than your symptoms. Borrowing a friend's or relative's medicine skips every one of those checks.

The cause of your symptoms may be different

Two people can have very similar symptoms for completely different reasons. Low mood, for example, can be part of depression, bipolar disorder, a thyroid problem or a side effect of another medicine, and each needs a different approach. Using the wrong treatment can mask a problem or make it worse.

The medicine may not be safe for you

• You may be allergic to it or to an ingredient in it.
• It may be unsuitable in pregnancy or while breastfeeding.
• Kidney, liver or heart conditions can change how a medicine is handled or make it risky.
• The dose that suits one person may be too high or too low for another.

It may interact with other things you take

Prescription medicines can interact with your regular medicines, over-the-counter products, herbal remedies, alcohol and even some foods. A prescriber or pharmacist checks for this; a friend handing you a few tablets cannot.

You may not know exactly what you are taking

Medicines that look alike can contain different drugs or strengths. Borrowed medicines may be out of date, may have been stored badly, or may come without the patient information leaflet that explains how to take them safely.

Your clinicians will not have the full picture

If you have a side effect or need emergency care, staff rely on your medical record and what you tell them. A medicine that was never prescribed to you will not appear on your record, which can delay the right treatment.

Is it illegal to share prescription medicines in the UK?

The law depends on the type of medicine:

Penalties for controlled drug offences can include fines and, in serious cases, imprisonment. Pregabalin and gabapentin became Class C controlled drugs in April 2019 because of growing concerns about misuse and dependence.

What should I do instead?

• Only take medicines prescribed or recommended for you.
• Do not lend, give away or sell your prescription medicines.
• If you run out, contact your GP practice or pharmacy; community pharmacies can sometimes provide an emergency supply of a regular medicine.
• If your symptoms are new or changing, ask a pharmacist for advice or book an appointment with a prescriber.
• Return unwanted or out-of-date medicines to a pharmacy for safe disposal rather than keeping them "just in case".

Frequently asked questions

Is it okay to give my partner one of my painkillers?

Not if it is a prescription-only medicine. Many prescription painkillers are controlled drugs, so passing them on may be an offence as well as a health risk. Suggest they speak to a pharmacist about suitable over-the-counter options.

What if a family member has the same condition as me?

Even with the same diagnosis, the right medicine and dose can differ because of age, weight, other conditions and other medicines. They should be assessed for their own treatment.

What should I do if I have already taken someone else's medicine?

If you feel unwell, contact NHS 111 or your GP, or call 999 in an emergency. Take the packaging with you so clinicians know exactly what was taken.

Can I use leftover antibiotics from a previous prescription?

No. Leftover antibiotics may be the wrong type or an incomplete course, and inappropriate use contributes to antibiotic resistance. Return them to a pharmacy.

Key takeaways

• Prescription medicines are tailored to one person and can harm someone else.
• Sharing controlled drugs, such as pregabalin, gabapentin, strong painkillers and ADHD stimulants, can be a criminal offence.
• Borrowed medicines will not be on your record, which can complicate emergency care.
• Pharmacists and prescribers can help you find safe, appropriate treatment.

Sources and further reading

• GOV.UK: Pregabalin and gabapentin to be controlled as Class C drugs
• MHRA Drug Safety Update: Pregabalin, gabapentin and risk of abuse and dependence
• NHS: Prescriptions

Last reviewed: October 2026 by Shamir Patel, Independent Prescribing Pharmacist, Ready Health. This article is general information and does not replace advice from your own clinician or legal advice.

If you have symptoms you would like to discuss with a clinician, book a consultation with Ready Health in Standish, Wigan. A prescriber will assess you individually and talk through suitable options.