Controlled Drugs Flashcards
What receptors do both Methadone and Buprenorphine bind to?
- Opioid receptors
- highest affinity for miu receptors
- found in CNS, nerves in the periphery, on cells in GI tract
What is the main indication of Methadone and Buprenorphine and how do they work?
- Pain Killers/Analgesics
- work through the CNS (brain and spinal cord) to
- alter the way pain impulses arriving from peripheral nerves are processed to
- change perception and tolerance of pain
- explained by Gate Control Theory
Tell me about the Gate Control Theory of pain?
- Transmission of pain impulses can be modulated all along the spinothalmic tracts
- All along the spinal cord, interneurons can act as ‘gates’ by blocking the ascending transmission of pain impulses
- (inhibitory influence of higher brain centres on transmission of pain impulses helps explain mystery around pain- culture, learned experiences and placebo)
What is the other indication of Methadone/Buprenorphine and why?
Treatment of recreational opioid-based drug dependence
Because they act on the same opioid receptors and therefore have the same effects of;
- slow-acting pain-response inhibitors and
- decreasing respiratory activity
Whilst ALSO inhibiting the euphoria associated with recreational opioid-based drugs
What are some of the difficulties of using Methadone/Buprenorphine to treat illicit-opioid dependence?
- Extreme similarities between signs and symptoms of withdrawal from drug itself and side effects
- Reduces tolerance to drug-risk of accidental overdose
- May precipitate withdrawal (buprenorphine)
What is the mechanism of action of Methadone?
- Opioid Receptors Agonist
What is the mechanism of action of Buprenorphine?
- It both agonises and antagonises Opioid Receptors-partial agonist!
Which patients are contraindicated for Methadone use?
- Patients with respiratory depression
- Patients with acute bronchial asthma
Which patients are contraindicated for Buprenorphine use?
- Hepetitis B or C patients
- Alcohol-induced psychosis patients.
Patient Education: Possible drug interactions?
Use alongside;
- Analgesic Barbiturates
- Antipsychotics
- Benzodiazepines
- MAOIs
increases the risk of the following;
- Respiratory depression
- hypotension
- sedation
- coma
Explain the shared side effects of Methadone and Buprenorphine
Action of receptors
- in chemoreceptor trigger zone (in the brainstem)
- on GI motility (negative effects)
both lead to GI side effects of
- nausea
- vomiting
- constipation
Additionally, may lead to impotence and infertility
What are the specific side effects of Methadone?
General:
- light headedness
- sedation
- sweating
Major:
- Dependence
- Respiratory and Cardiac Arrest (call 999)
What are the specific side effects of Buprenorphine?
General;
- Dizziness
- Numbness
- Insomnia
- Headaches
Other;
- Less abuse potential as blocks opioid receptors that may be stimulated by other opioids
- Less sedating than Methadone
Tell me about the absorption rates of different administration methods for Methadone?
- IV is the most reliable way to achieve therapeutic levels
- IM and subcutaeneous offer inconsistent rates of absoprtion-heavily dependent on individual physiology
- With tablets, extra care not to cut, crush or chew as entire dose can be given at once!
- Slower in females than males
- Long-acting
Tell me about the absorption rates of different administration methods for Buprenorphine?
- IM -absorbed rapidly
- IV very rapid absorption-reaches peak levels
Where are Methadone/Buprenorphine metabolized and excreted?
- Hepatic metabolism
- Methadone; excreted urine and bile
- Buprenorphine; excreted in urine and faeces
What is the process for administering Controlled Drugs?
- (P)Check prescription
- (S)Check stock level in locked CD cupboard
- (E)Enter date, time, patients name, amount given, form and remaining balence in the CD record book.
- (P)Prepare drug and take to patient with CD record book and drug administration chart
- (A)Check and administer
- (S)Sign CD record book and drug administraion chart
Two signatures required and any excess/waste must be recorded appropriately (specific CD disposal protocol and method)
Why is it important that the nurse in charge of the ward has possession of the keys?
They are responsible for the Controlled drugs until they handover to the next shift.
