More than 450 lives were cut short by the inappropriate use of opioids at Gosport War Memorial Hospital.
Opioids are a group of medicines used to treat pain.
The drugs are either made from the opium poppy or are synthetic or semi-synthetic medicines chemically similar to those made from opium.
The drugs work by imitating the body’s natural pain-relievers and come in different strengths.
Examples of weak opioids include codeine, dihydrocodeine and tramadol.
Strong opioids include morphine, diamorphine, oxycodone, fentanyl, methadone and buprenorphine.
People are usually prescribed strong opioids when they are in significant pain for reasons such as trauma or disease.
Opioids are also occasionally prescribed to reduce breathlessness in palliative care.
But at higher doses opioids can depress respiration, with death from an opioid overdose usually due to respiratory arrest.
Older people are particularly susceptible to the adverse effects of drugs in general, and opioids in particular.