The strong analgesics morphine and codeine are opiates. Outline how codeine can be synthesized from morphine. The structures of morphine and codeine are in section 37 of the data booklet.

Explain why opiates are addictive.

Morphine and diamorphine (heroin) are both opioids.

Explain why diamorphine is more potent than morphine using section 37 of the data booklet.

Morphine and codeine are strong analgesics. Outline how strong analgesics function.

Explain why diamorphine (heroin) is more potent than morphine using section 37 of the data booklet.

Explain how opiates act to provide pain relief.

State and explain the action of opiates as painkillers.

Explain why diamorphine passes more readily than morphine through the blood-brain barrier.

Suggest the type of reaction used to convert morphine to codeine.

Suggest a reagent used to prepare diamorphine from morphine.

Explain why diamorphine (heroin) crosses the blood–brain barrier more easily than morphine.

Suggest one reason why codeine is available without prescription in some countries whilst morphine is administered under strict medical supervision.

Methadone is sometimes used to help reduce withdrawal symptoms in the treatment of heroin addiction. Outline one withdrawal symptom that an addict may experience.

Explain why diamorphine (heroin) crosses the blood–brain barrier more easily than morphine.

Explain how opiates act to provide pain relief.

State one advantage of using morphine as an analgesic.

Explain why diamorphine (heroin) is more potent than morphine using section 37 of the data booklet.

Suggest one reason why codeine is more widely used than morphine as an analgesic.

Discuss how the difference in structure of two opiates, codeine and morphine, affect their ability to cross the blood–brain barrier. Use section 37 of the data booklet.

Discuss how the difference in structure of two opiates, codeine and morphine, affect their ability to cross the blood–brain barrier. Use section 37 of the data booklet.