Narcotic Opioid Analgesics Flashcards
Morphine is a _____ opioid agonist while Codeine is a ______ opioid agonist. Thebaine is a _______ for other opioid drugs.
- strong
- weak
- Precursor
Endogenous opioid peptides or otherwise known as endorphins have 3 major families. They are the _______ , ________ (pentapeptides) and _________.
- Beta-endorphins
- Enkephalins
- Dynorphins
The brain has modulatory circuits to regulate the perception of pain. Attitude, mood, and physical exercise can ___________ pain. It is better to control pain before it ________.
- influence the perception of
2. becomes severe
The pain pathway starts from primary afferent neurons (in periphery) to the thalamus via the __________. The amplitude of the pain signal can be modulated via an efferent pathway (-) that reduces depolarization of __________ signal.
Spinothalamic tract (+)
Opioids work by inhibiting of the ______ of pain signals, altering the _______ of pain and possibly elevating the _______(?).
- propagation
- emotional perception
- pain threshold
Opioid receptors are located at ________ nociceptive terminals (peripheral analgesia), The spine (spinal analgesia) and The _____ (supraspinal analgesia).
- Peripheral
2. brain
The 3 major subtypes μ (Mu), δ (Delta) and κ (Kappa) are all _________ receptors. Majority of functional effects are due to action of _____ and ______.
- G Protein Coupled
- μ (Mu)
- κ (Kappa)
______ seems to be major receptor in both analgesic and psychoactive effects except dysphoria (feeling of unease, discomfort) while ______ is the major receptor sub type for dysphoria.
- μ (Mu)
2. κ (Kappa)
At _____ doses, opioids have beneficial sedation and analgesic effects by acting on nociceptive terminals, spine and brainstem.
Lower
At higher doses, opioids have side effects such as Reduced ______, Euphoria, Pupil constriction, Dysphoria, Severe sedation and _______ (potentially fatal) due to effects on GI tract, “emotional brain”, ________, respiratory nuclei.
- gut motility
- Respiratory depression
- Occulomotor
Elderly patients usually require a ______ dose of opioids to achieve effective pain relief than younger patients.
lower
Neuropathic pain usually requires ______ opioid doses than nociceptive pain.
higher
______ doses are usually required for continuous maintenance of pain relief than administration in response to recurrence of pain.
Lower
Opioid analgesics should be started at _______ and carefully titrated until _______ is obtained (based on patient response), or until persistent and unacceptable _____ warrant a re-evaluation of therapy.
- a low dose
- an adequate level of analgesia
- side effects
Failure of at least _______ with incremental dosing in the ______ patient may indicate that the pain syndrome is unresponsive to opioid therapy.
- partial analgesia
2. opioid-naive
For some patients with chronic pain, opioids do not exert an appreciable analgesic effect until _________ has been achieved.
a threshold dose
Opioids have many clinical uses. Analgesia: Codeine, morphine, pethidine Anaesthetic adjuvant: \_\_\_\_\_\_ Cough suppressant / antitussive: \_\_\_\_\_\_\_ Anti-diarrhoeal: \_\_\_\_\_\_\_\_
- Fentanyl
- Codeine
- Diphenoxylate
Morphine is a ______ μ agonist ( _____δ and κ agonist). It has _____ maximum analgesic efficacy and liability for addiction/abuse.
- Strong
- weaker
- high
Methadone and Fentanyl are _____ μ agonists ( _______ δ and κ affinity). They have ____ maximum analgesic efficacy and liability for addiction/abuse.
- Strong
- no significant
- high
Methadone and Fentanyl are _____ μ agonists ( _______ δ and κ affinity). They have ____ maximum analgesic efficacy and liability for addiction/abuse. Methadone is ____ -acting (plasma half-life > 24 hrs) while Fentanyl is ____ -acting (anaesthetic adjuvant).
- Strong
- no significant
- high
- long
- short
Pethidine(Meperidine) is a _____ μ agonist (probably _____ δ and κ agonist). It has a _____ duration of action than morphine (especially in neonate therefore used in labour).
- Strong
- weaker
- Shorter*
- good as it is less likely to remain in neonate, more useful in labour
Pethidine(Meperidine) is N-demethylated in the liver to _______ , leading to ___________ effects at high doses.
- norpethidine
2. hallucinogenic and convulsant
Pethidine(Meperidine) causes ______ rather than sedation and has Antimuscarinic effects (i.e. parasympatholytic) therefore dry mouth, blurring of vision but no _____ and less _____ of smooth muscle.
- Restlessness
- miosis
- spasm
Codeine/ Dihydrocodeine is a ____ μ and δ agonist (probably ____ κ agonist) with _____ maximum analgesic efficacy. It carries ______ liability for addiction/abuse.
- Weak
- not a
- Low
- Moderate
~10 % of codeine/ Dihydrocodeine is converted to morphine / dihydromorphine which leads to ~10 % of population showing _______ effect due to lack of demethylating enzyme.
reduced analgesic
Tramadol is a _____ μ agonist and also a _____ inhibitor of 5-HT and noradrenaline re-uptake. It is noted that ondansetron (serotonin 5-HT3 receptor antagonists) reduces analgesic effect of tramadol, meaning tramadol may mediate analgesic effect via ______ MOA (theory).
- Weak
- Weak
- 5-HT
Opioids can cause respiratory depression via Actions in the nucleus tractus solitarius and nucleus ambiguus. This reduces ______ to CO2 (and H+) and suppresses ________. Opioids should be avoided in ______.
- responses
- voluntary breathing
- Infants
Respiratory depression should not occur at normal therapeutic doses but can be lethal in:
- overdose
- ______ disease
- _____ dysfunction
- combination with other ________ drugs
- __________ patient group
- respiratory
- hepatic
- CNS depressant
- Young children
Opioid induced Nausea / vomiting most probably due to actions on the _____________ in the area postrema of the medulla (usually reduces with ________ use).
- chemoreceptor trigger zone
2. repeated or chronic
Constipation is caused by opioids due to reduced gastrointestinal motility (esp. with _____ use). Opioids can also cause ________, which may require caution against operating machinery or driving.
- chronic
2. Drowsiness
Opioids cause ______ (pinpoint pupils) due to actions in the oculomotor nucleus. ______ is a diagnostic feature of opioid overdose. But we should note that mydriasis can also follow if hypoxia occurs.
Miosis
Opioids cause _______ due to increased bladder sphincter tone (esp. in patients with ____________.)
- Urinary retention
2. prostatic hypertrophy
Opioids cause ___________ and ________ due to actions in cardio regulatory nuclei in the medulla.
- Postural hypotension
2. bradycardia
Opioids carry an _______________ effect with long-term use, most likely through CNS effects on the immune system.
Immunosuppressant
Morphine can also trigger _________, leading to urticaria and itching, bronchoconstriction and hypotension due to vasodilatation. As such, Morphine should be used with caution in _________.
- histamine release from mast cells
2. asthmatics
Opioids have Tolerance issues meaning they are ____ effective after prolonged use and dose ______ required. Together with addiction tendencies, opioids can lead to risk of overdose.
- less
2. escalation
Physical Dependence on opioids can manifest as physical withdrawal symptoms. They include: _____ , ______ , chills, hot flushes, _____ pain, lacrimation (tears), rhinorrhea (runny nose), nausea, vomiting, abdominal cramps, ______.
- anxiety
- irritability
- joint
- diarrhea
Opioid antagonists should be used with extreme caution in patients with opiate dependency as they can precipitate potentially fatal ________.
withdrawal syndrome
Opioid antagonists such as Naloxone/ Naltrexone/ Nalmefene show _____ μ antagonism; also δ and κ antagonism. They are used to counteract ________.
- Strong
2. opioid overdose
Naloxone is _____-acting (usually intravenous for immediate overdose crisis)
Naltrexone is long-acting (____ administration post crisis and also used for ___________________________)
Nalmefene is long-acting ( _______ administration) and can replace Naloxone + Naltrexone.
- short
- oral
- long term treatment of addiction
- intravenous
