What are highly addictive opiates?

All of them.: Any opiate may become the object of addiction. Some of the opiates are very potent, such as fentanyl, but the potency only affects the dose required for intoxication, and not the potential for addiction.

Any opioid: Can be highly addictive to susceptible people. But there is a difference between dependence and addiction. Dependence means that your body accomodates to the effects of the drug. If the drug is then suddenly withdrawn, you go through a withdrawal syndrome. Addiction involves using opioids for other than the prescribed reason or in increasing amounts to get the same effect.

Any can be: Although the likelihood of getting addicted to opioids if taken as prescribed for pain is low, all opioids have the potential.

All: All of them. But, shorter acting opiates may be more addictive than longer-acting opiates.