Codeine Phosphate OD 15-60mg oral route: The recommended dose is 15-60mg every 4 to 6 hours. One of patient X's past medications. Indications: Codeine is an opioid analgesic used to treat patient X's mild to moderate pain. Codeine is an opioid and an agonist of the mu opioid receptor. It's mechanism of action acts on the central nervous system. Opioid receptors are G-protein coupled receptors that positively and negatively regulate synaptic transmission via downstream signalling. Binding of codeine to the mu opioid receptors causes hyperpolarisation of the neuron, thus inhibits the release of patient X's nociceptive neurotransmitters causing an analgesic affect. It is metabolised in the liver. Its peak is 15-30 minutes with a half-life of 2.5-3 hours and lasts for approximately 4-6 hours. Contraindications include alcohol intoxication, cor pulmonale, hypotension, and decreased function of the adrenal gland. Side effects include drowsiness, constipation, lightheadedness, dizziness, sedation, shortness of breath, nausea, vomiting, and gastrointestinal upset. In patient X's case, COPD patients may be prescribed codeine to relieve musculoskeletal pain, insomnia and respiratory issues. However, codeine should be taken with caution as it can induce additional respiratory adverse effects. Interactions include alcohol, opioid antagonists, monoamine oxidase inhibitors, anticholinergics, and anti-diarrhoeal drugs (Mckenna & Lim, 2014).
Legal guidelines: Codeine phosphate is a controlled class C2 drug except when specified in Schedule 3 part 6 of the Misuse of Drugs Act 1975. Under the Misuse of Drugs Act 1975 every prescription for a controlled drug must be signed physically by the prescriber in his or her own handwriting (Ministry of Health, 2019).
Under regulations 29 the prescription must include the date, name and address of the patient, name of the medication, dose and frequency, and the prescriber's name and address (Ministry of Health, 2019).
Amendments to controlled drug prescriptions are only to be made by the prescriber, who must sign for the changes (Ministry of Health, 2019).
Due to codeine being a controlled class C2 drug the transitioning nurse cannot administer this to patient X as under the Health Practitioners Competence Assurance Act 2003, this is beyond their scope of practice (Ministry of Health, 2019). However, the transitioning nurse may be a third checker of controlled medications. All three nurses are responsible for checking the medication, medication expiry date, prescribed dose, patient name and date of birth (NZNO, 2018).
A register of all controlled medications must be kept and it is the responsibility of the employer to facilitate this (Ministry of Health, 2019).
Under Section 28 of the Misuse of Drugs Regulations 1977 states that every person in possession of a controlled drug in the duration of their profession shall keep the drug in a locked cupboard/compartment that is made of concrete, metal or both and ensure it is securely fixed to the building. The key to the access of the cupboard must be kept in a safe place at all times when not in use (NZNO, 2018).
All people who administer controlled medication shall familiarise themselves with their employers policies and practice procedures on this topic (NZNO, 2018).