Pain management Flashcards by Lin Weilin

Learning Objectives
• At the end of the session, you will be able to
• Understand the importance of pain management
• Define, Classify and Describe different types of pain
• Describe the key steps in pain assessment
• Describe the principles of pain management

Compare and Contrast the different types pain
medications, including basic dose conversion and titration
- key features of drugs, specific dosage forms
- what to note when starting doses
- some dose titrations are key
- management of side effects as a whole class (N/V/Constipation)

How well did you know this?

Not at all

Perfectly

The total concept of pain involves 4 key factors which are __, __, __ and __.

Physical
Psychological
Social
Spiritual

How well did you know this?

Not at all

Perfectly

A poor __ or __ of pain can cause patients to over-report pain.

past experience

2. anticipation

How well did you know this?

Not at all

Perfectly

Pain is a __ and __ response that varies daily between individuals. It can reflect the quality of __ and may be evidence of __.

physiologic
psychological
care/life
under-treatment

How well did you know this?

Not at all

Perfectly

Chronic pain is defined as pain that persists even after __. This duration varies depending on the __ and may last anywhere from 4-6wks to 3months.

sufficient time provided for an insult/injury to heal

2. type of injury

How well did you know this?

Not at all

Perfectly

There are 4 types of pain classified according to pathophysiology, which are __, __, __ and __.

Nociceptive Pain, Neuropathic Pain, Referred Pain and Ischemic Pain

How well did you know this?

Not at all

Perfectly

Nociceptive pain is due to actual nociceptive input (in terms of __. It can be subdivided into __ and __.

tissue damage

2. somatic and visceral pain

How well did you know this?

Not at all

Perfectly

Somatic pain occurs when nociceptors are triggered by noxious stimuli (__, ___ or __ types). These signals are carried by small myelinated A delta fibers (__ stimuli) and C fibers (__) to the dorsal horn of the spinal cord.

mechanical, thermal or chemical
mechanical and thermal
all three stimulus types

How well did you know this?

Not at all

Perfectly

Somatic pain can be subdivided into __ and __ somatic pain. Somatic pain is __ to the site of injury, is constant and sometimes feels like it is __.

cutaneous
deep
tender and localized
throbbing or aching

How well did you know this?

Not at all

Perfectly

Visceral pain is mediated by __ receptors. It is poorly __ and often referred to a __ which may be tender. Patients may find it difficult to pinpoint the exact location.

stretch
localized
distant cutaneous site

How well did you know this?

Not at all

Perfectly

Patients may describe it as __, __ and __ (eg, appendicitis, cholecystitis). It is a good idea to relate to __ to find possible pressing forces on viscera.

deep, dull, and cramping

2. patient history

How well did you know this?

Not at all

Perfectly

Neuropathic pain is caused by __ in either the peripheral or central region. It may be due to __ or its __ (diabetes, infection, cancer, drugs, radiation).

injury to the nerves
disease
treatment

How well did you know this?

Not at all

Perfectly

Neuropathic pain is often described as prolonged, severe, __, __ , or squeezing , and is often
associated with __. If severe, neuropathic pain may be accompanied by weakness.

burning
lancinating
focal neurologic deficits

How well did you know this?

Not at all

Perfectly

In neuropathic pain, there may be no __, but areas of __ (allodynia). It is also characterized by its relative __, making it the most challenging type of pain to treat.

area of tenderness
exquisite sensitivity to normally innocuous stimuli
resistance to opioids

How well did you know this?

Not at all

Perfectly

__ neuropathic pain results from abnormal nerve generation while __ neuropathic pain results from reorganization of central somatosensory processing.

Peripheral

2. central

How well did you know this?

Not at all

Perfectly

Referred pain is pain __. It may occur because signals from different part of body travel along the __ going to the spinal cord and the brain.
• i.e. Obstructed bile duct produces pain near right side of scapula
• i.e. Hip injury pain referred to the knee

located away from its point of origin

2. same pathways

How well did you know this?

Not at all

Perfectly

Ischaemic pain is caused by __ to tissue (poor/no perfusion to area), leading to tissue hypoxia and damage. This causes a release of inflammatory mediators and chemicals that stimulate nociceptors
• i.e. Angina Pain

loss of blood flow

How well did you know this?

Not at all

Perfectly

Pain that feels aching, stabbing, throbbing, or pressure is likely to be __ pain, originating from __.

Somatic (Nociceptive)

2. skin, muscle, bone

How well did you know this?

Not at all

Perfectly

Gnawing, cramping, aching, or sharp pain is likely to be __ pain, originating from __.

Visceral

2. Organs or viscera

How well did you know this?

Not at all

Perfectly

Burning, tingling, shooting, or electric /shocking pain is likely to be __ pain, originating from __.

Neuropathic

2. nerve damage

How well did you know this?

Not at all

Perfectly

Pain evaluation of patients can be subjective via __ (even if tissue damage cannot be observed) or objective via autonomic signs associated with acute pain, (increase __) especially in unconscious patients.

signs of distress

2. RR, HR, BP, diaphoresis

How well did you know this?

Not at all

Perfectly

When taking pain history, the usage of __ can help elicit more details. History should be __ and we have to look out for __ (consider total concept).

open-ended questions
taken separately for each pain
signs of psychological distress

How well did you know this?

Not at all

Perfectly

The SOCRATES framework can help get a good pain history:
• S__: Where is it?
• O__: When did it start? How did it start?
• C__: How does it feel? (look for neuropathic pain)
• R__: Does it run anywhere?
• A__: A ny other symptoms?
• T__: How long have you had it?
• E__: What makes it worse/better?
• S__: How bad is it? (using 1-10 subjective scores)

site
Onset
Character
Radiation
Associations
Time course
Exacerbating/relieving factors
Severity

How well did you know this?

Not at all

Perfectly

The goal of pain assessment is to:
• \_\_ the pain
• Identify pain syndrome (Acute/chronic/breakthrough, Cancer/Non cancer related)
• Infer \_\_ (Nociceptive/Neuropathic)
• Evaluate physical and psychosocial \_\_
• Assess degree and nature of \_\_
• Develop a therapeutic strategy

Characterize and Quantify
pathophysiology
comorbidities
disability

How well did you know this?

Not at all

Perfectly

General tool for quantifying pain intensity is via the __. When assessing pain for children and elderly who do not verbalize well, the __ tool is preferable (ensure the score is patient-reported and not by healthcare professionals!!).

1. Numerical rating scale | 2. Wong-Baker Faces Rating Scale

For patients who cannot self-report pain (i.e. < 3 years old), the FLACC scale (f_, L_, A_, C_, C_) is recommended. Each factor is scored 0-2, and the sum is reported on a scale of 0-10.

1. face, legs, activity, cry, consolability

The __ assessment tool is based on a 10cm line where patient can make a marking on the line to indicate where their pain is. It is mainly used in the research setting to attempt a more 'objective' measure of pain.

visual analog scale

The __ assessment tool allows patients to assess their pain using various adjectives i.e. annoying, dreadful, agonizing etc..

adjective rating scale

The __ pain questionnaire is often used to measure effectiveness of analgesics. It measures 3 dimensions of pain: 1. Sensory (location, temporal pattern, quality) 2. Affective (emotional response) 3. Evaluative (perceived intensity)

McGill-Melzack

Pharmacotherapy options for pain management include: - __ (opioids and non-opioids) - __ blocks - Adjuvant analgesics (neurophatic, musculoskeletal)

1. Analgesics | 2. Nerve

Alternative methods for pain management include: 1. Electric stimulation (TENS/PENS) 2. a__ 3. __ therapy 4. c__ 5. Surgery

1. Acupuncture 2. Physical 3. Chiropractics

The 3 key principles of pain management: 1. Treat the __ where possible 2. Ask what is the __ behind the pain 3. Pharmacological Treatments via __

1. underlying cause 2. Pain Mechanism(s) 3. WHO LADDER

WHO treatment guide for cancer recommends: 1. __ ROA recommended 2. Regular __ of analgesia 3. __ regimen 4. Treat according to __ 5. Constant __ (attention to detail)

1. PO 2. intervals 3. Individualize 4. patient's perception 5. monitoring

We should match analgesic choice to severity of pain and titrate to response. • __ titration for severe pain. • __ titration for moderate pain. • __ titration for mild pain.

1. Rapid 2. Slower 3. Even slower

20% of cancer pain requires multi dimensional approach: | - __ of pain syndrome, use of 2nd line agents and/or __ interventions.

1. reassessment | 2. non-pharmacological

Based on WHO pain ladder, a pain score of 1-3 (mild pain) should be treated using: 1. __ if patient is not on analgesics (aspirin generally avoided due to __ effect) 2. __ and __ if patient is already on analgesics (i.e. max dose)

1. Paracetamol/NSAIDs 2. irreversible anti-platelet 3. Short-acting opioid and bowel regimen

Paracetamol is dosed 500-1000mg doses every 6 to 8 hourly; Max dose: __. It is the most commonly used non-opioid but we have to be cautious of overdose from using different __.

1. 4g/day | 2. combination products

Paracetamol has a low incidence of _(1)_, high oral/rectal _(2)_, multi-preparations available and is __(3)_____ with opioids. However, it lacks ___(4)______ and can cause __(5)____ with large doses (avoid > 3 grams/day for elderly).

1. ADR 2. bioavailability 3. synergistic 4. anti-inflammatory action 5. hepatotoxicity

Paracetamol is metabolized in the __ and eliminated in the __. We should watch out for patients with compromised __ function.

1. liver 2. kidney 3. liver and kidney

When choosing NSAIDs, there is no preference and any cost-effective NSAID __ by patient can be used. Alternatively, we may consider the PO equivalent of max tolerated __ dose.

1. tolerated | 2. ibuprofen

If two NSAIDs are tried in succession without efficacy, we should __.

use another approach to analgesia

COX‐2 selective NSAIDs are associated with lower incidence of __ side effects and do not inhibit __. However, they are more __ than traditional NSAIDs.

1. GI 2. platelet aggregation 3. expensive

NSAIDs are extensively protein bound and excreted mainly in __. They can appear in __ and cross the __.

1. urine 2. milk 3. placenta

NSAIDs can cause __ side effects and reversible platelet inhibition. They should be avoided if patients are on chemotherapy (may develop __). Coxibs would be preferable in this case.

1. GI | 2. thrombocytopenia

NSAIDs can cause: • __ effects: edema, HTN, renal failure • CNS: headache, dizziness, nervousness and visual disturbance • Cardiovascular effects: edema, cerebrovascular accident, hypertension, MI • __ (esp classical NSAIDs i.e. indomethacin & mefanamic acid, diclofenac) • __ : hemolytic anemia, pancytopenia, thrombocytopenia Other SE: ________ platelet inhibition, ____

1. Renal 2. Hypersensitivity reaction 3. Hematological 4. reversible 5. GI SE

``` NSAIDs should be avoided in: • Elderly (>65 years) • __ disorder • __, bronchospasm • __ disease (ulcers, bleeding) • Cardiovascular disease • __ or Hepatic dysfunction • Receiving __ ```

1. Bleeding 2. Asthma 3. GI 4. Renal 5. anticoagulants

NSAIDs DRUG INTERACTIONs 1. Increased risk of bleeding (Anticoagulants and Antiplatelet drugs) 2. Increased risk of __ (ACE inhibitors, ciclosporin, tacrolimus, or diuretics) 3. Increased risk of GI ulceration (__) 4. Reduced __ effects (ACE inhibitors, beta blockers, and diuretics)

1. nephrotoxicity 2. corticosteroids 3. antihypertensive

Adjuvants for neuropathic pain includes: __, __, antidepressants, antiepileptics and topical lidocaine.

1. Gabapentin | 2. pregabalin

__ can be used as an adjuvant for: Bone pain, neuropathic pain, raised intracranial pressure, liver capsule stretch pain

Corticosteroids

NSAIDs and bisphosphonates are adjuvants for __ pain.

Bone

Muscle relaxants e.g. __ and __ are useful adjuvants for Cramps or muscle spasm

1. baclofen | 2. benzodiazepines

Hyoscine butylbromide are useful adjuvants for __.

Intestinal colic

Based on the WHO ladder, a patient with a pain score of 4-6 (moderate pain) should be started on a __ agonist. A patient with a pain score of 7-10 (severe pain) should be started on a __ agonist.

1. weak opioid | 2. strong opioid

Opioids can have effects other than analgesia as a__, a__, s__ and for severe __ (in patients as an allergic alternative).

1. antitussives 2. antidiarrheals 3. sedatives 4. Headache

Codeine Phosphate has good onset of __, but a short duration of 4-6h. It can cross the placenta and enter the breast milk. Codeine is metabolized in the __ to morphine and excreted in the __.

1. 0.5-1h (PO) 2. liver 3. urine

The Equianalgesic dose of codeine is: 200mg (oral) codeine = __ mg(IM/SC) Morphine = __mg (IV) codeine

1. 10 | 2. 100

Codeine phosphate and Tramadol are major substrates of __ and may have reduced effects from __ such as chlorpromazine, fluoxetine, miconazole, paroxetine, quinidine and quinine.

1. CYP2D6 | 2. CYP2D6 inhibitors

Codeine causes __ but patients are expected to develop tolerance after 2 weeks. It can also cause __ (no tolerance will develop).

1. drowsiness | 2. constipation

Tramadol is an opioid agonist that also inhibits reuptake of __ and __, allowing it to have good __ and __ analgesic effect.

1. noradrenaline 2. serotonin 3. somatic and neuropathic

Tramadol is favorable clinically due to its lesser __ and __ side effects compared to other opiates along with a __ potential for abuse.

1. cardiovascular 2. respiratory 3. “Low”

Tramadol has a onset of action of __ with a duration of 9hrs (allowing for longer intervals). It is metabolized exclusively hepatically via __ to a active metabolite and excreted __.

1. within 1hr 2. CYP2D6 3. in the urine

Dosing adjustment for codeine and tramadol are necessary in patients with __ or __ impairment.

1. liver | 2. renal

Tramadol comes in __ and __ ROAs but regardless of ROA, has a max dose of __ (unlike other opioids who do not have ceiling doses).

1. injection 2. tablet 3. 400mg/day

At high doses of Tramadol, it can __ which explains why it should be avoided in patients __ i.e. patients with brain tumors or patients on drugs with __ (Neuroleptic agents, SSRIs and TCAs).

1. lower the seizure threshold 2. pre-disposed to epileptic activity 3. CNS activity

Tramadol can cause CNS side effects: __, headache, somnolence and GI side effects: __, ___

1. Dizziness | 2. Constipation, nausea

__ may increase risk of seizures if used together with Tramadol while concomitant use of warfarin and tramadol may lead to __. Carbamazepine can ______ half-life of tramadol by 33 to 50%

1. Naloxone, neuroleptic agents, SSRIs, TCAs 2. elevated prothrombin times 3. decrease

Morphine has a good onset of action: __ (PO) and __ (IV). It is metabolized in the __ to active metabolites and excreted mainly in the __. active metabolite: _____

1. 30min (PO) 2. 5-10min (IV) 3. liver 4. urine 5. morphine-6-glucuronide

The oral : parenteral ratio of morphine is __.

3 : 1

Morphine is available in a variety of ROAs: : Injection, mixture, tablet and capsule. Dose adjustments are required for __. Excessive sedation may occur in patients with __.

1. renal impairment | 2. cirrhosis

Morphine can cause GI side effects of __ (tolerance usually develops), __ (with chronic use) and __ (reason for bowel regimen).

1. Nausea 2. vomiting 3. Constipation

Morphine can cause __ (may be increased with antipsychotics), drowsiness, __ (secondary to histamine release) and __ (esp in epidural or intrathecal use).

1. hypotension 2. pruritis 3. urinary retention

Patients on morphine should avoid the following as they may increase its effects/toxicity: 1. CNS depressants 2. __ 3. __ (some manufacturers recommend 14 day wash out) 4. Herbs/nutraceuticals (Avoid valerian, St John's wort, kava kava, gotu kola) 5. _____ increase hypotensive effect of morphine

1. Alcohol 2. MAOI 3. antipsychotic

Fentanyl has an almost immediate onset: __ (IM), __ (IV). It is mainly metabolized hepatically via __ and excreted in __.

1. 7-15min 2. almost immediate 3. CYP3A4 4. urine

Fentanyl is about 100 times more potent than morphine. The equianalgesic dose is 100 mcg (IM) fentanyl = __ mg (IM) morphine

10mg

__ is a great opioid in the sense that it has no dose adjustments for hepatic/renal impairment (only requires monitoring in hepatic impairment).

Fentanyl

``` Transdermal fentanyl is used only if: • intolerable undesirable side effects from __ • __ failure • inability to __ • ‘tablet phobia’ or poor __ ```

1. morphine 2. renal 3. swallow 4. oral compliance

Transdermal fentanyl patches achieve steady state concentrations after __ (delayed onset) and have a duration of action of __ (48h for fast metabolizers). The elimination half life post patch removal is __.

1. 36-48h 2. 72h 3. 13-22h

Patients may experience withdrawal symptoms when switching from PO morphine to TD fentanyl despite satisfactory pain relief due to __. These withdrawal symptoms include: e.g. colic, diarrhoea, nausea, sweating and restlessness.

Different impact on peripheral and central µ opioid receptors.

The rate of absorption of TD fentanyl may be increased in __ patients or if the patch's skin area gets __ due to external heat source i.e. electric blanket/heat pad. __ may be a sign of fentanyl overdose.

1. febrile 2. vasodilated 3. A very sedated patient

It is preferable to place patches on __ areas. __ the hair is preferred over shaving (may shave off epithelial layers and increase absorption rate). Used fentanyl patches should be __ before disposal as it still contains some drug.

1. less hairy skin 2. Cutting 3. folded inward

TD fentanyl have an onset of __ and can accumulate in the __, with effects lasting 12h after the patch is removed. As such, no __ is required when switching patches. However, when switching from TD fentanyl to another opioid, __ is required to provide time for fentanyl to be excreted.

1. 6h 2. subcutaneous fat 3. break 4. a break of 12h

Methadone is a µ opioid receptor agonist, an __ receptor channel blocker and a presynaptic blocker of __ re-uptake. It is available as oral tablets and have an onset of __. Its duration of action increases from 4-5h to 6-12h with repeated doses.

1. NMDA 2. serotonin 3. 30min

Methadone is mainly metabolized in the liver via __, CYP2B6, and CYP2C19. Therefore, it makes sense that Methadone levels will be affected by __ inducers/inhibitors. It is excreted mainly in the urine.

CYP3A4

Avoid __ and herbs/nutraceuticals for patients on Methadone (i.e. St John's wort, valerian, kava kava, gotu kola. As Methadone is metabolized by CYP3A4 (intestinal), avoid __.

1. ethanol | 2. grapefruit juice

For methadone, dosage adjustment is required for __ impairment. Avoid in __.

1. renal | 2. severe liver disease

Generally for opioids, tolerance for adverse effects may develop over time; however, constipation and __ (especially bad for methadone) may persist. Other possible side effects of methadone include: h__, d__ and N/V.

1. sweating 2. Hypotension 3. Drowsiness

Oxycodone has a good onset of action: __min (PO) with a long duration of action: __ (IR) and __ (CR). It is metabolized hepatically to active metabolites and excreted in the urine.

1. 20-30 2. 4-6h 3. 12h

Dosage adjustment of oxycodone is required in __ impairment. Its adverse effects are similar to other opioids: d__, __ and constipation.

1. renal/liver 2. drowsiness 3. N/V

Oxycodone is an useful morphine alternative with about __ the potency and a longer duration of action (__ vs morphine 4h).

1. double | 2. 6h

Since oxycodone is metabolized to active (more potent) metabolites by __ , __ inhibitors (i.e. chlorpromazine, fluoxetine, miconazole, paroxetine, quinidine, quinine) are expected to __ effects of oxycodone. Oxycodone is also a major substrate of CYP3A4.

1. CYP2D6 2. CYP2D6 2. decrease

Patients on oxycodone should avoid __ and __ i.e. valerian, St John's wort, kava kava, gotu kola as they may increase CNS depression.

1. ethanol | 2. Herbs/Nutraceuticals

Tapentadol requires no dose adjustment in __ renal impairment and __ hepatic impairment. Dosages exceeding __ mg daily on the first day of therapy or __ mg daily on subsequent days have not been evaluated and are not recommended.

1. mild/moderate 2. mild 3. 700 4. 600

Pethidine requires dose adjustment in renal and hepatic impairment. The equianalgesic dose is __ mg (IV) pethidine = __ mg (IM/SC)morphine.

1. 75 | 2. 10

Pethidine is not commonly used in palliative care as: • Quick onset, short duration of action (2-3h). Not good for regular analgesia, and increases risk of __ • Toxic metabolite (norpethidine) which accumulates if given regularly, esp. in Renal failure • Norpethidine decreases __ • More __ than morphine

1. dependence 2. seizure threshold 3. emetogenic

Pethidine has a quick onset __ (IV) and __ (SC). It is indicated for __ pain and has less prominent CVS/GIT side effects compared to morphine.

1. 5min 2. 10-15min 3. acute

A minimal 24h morphine PO dose of __-__ mg is required before patients are candidates for conversion to __mcg/h fentanyl patch. A minimal 24h morphine PO dose of 30mg is required before patients are candidates for conversion to 12.5mcg/h fentanyl patch. (refer to manufacturer's table)

1. 45-134 | 2. 25

The equianalgesic dose ratio for tramadol and morphine is __ : __.

5 Tramadol : 1 Morphine

Conversion of morphine to methadone is complicated and done __.

stepwise over 3 days

When switching from 1 opioid to another, a __ is common (especially in __ patients or patients with __ dysfunction). Converting to methadone requires larger reduction (75-90%); depends on the dose of prior opioid.

1. 25-50% dose reduction 2. elderly 3. organ

Dose reductions when switching opioids may not be necessary when: Converting to __ (6h onset delay) Patients have __ (likely to be under-treated)

1. transdermal fentanyl | 2. severe pain

General principles of opioid use: 1. Choice and dose based on __ 2. Dose on a __ 3. Switch to __ to improve compliance 4. Consider alternatives if ineffective

1. severity of pain 2. regular basis 3. SR preparation

Breakthrough opioid doses are dosed at __. They may be dosed hourly as needed.

1/6 of the total daily dose

The total daily dose should be re-titrated when __. It also depends on the __ of the regimen.

1. breakthrough doses used daily exceeds 3 or 4. | 2. patient's tolerance

For patients previously on a weak opioid switching to morphine, give __ or modified release __. For frail, elderly and opioid naïve patients switching to morphine, give half of the standard dose (i.e. __).

1. 10mg q4h 2. 20-30mg q12h 3. 5mg q4h

Naloxone is an opioid antagonist used for treating __. It has a rapid onset of __ (IV), is metabolized in the liver and excreted in the kidney. In children, it is dosed by __ while adults follow the hospital's dosing protocol.

1. over dosage of opioids 2. within 2min 3. body weight

Common side effects of opioids include: • N__ (tolerance expected within 1-2wks) • C__ (unlikely to develop tolerance) • S__, mental clouding (Advise against driving, tolerance possible)

1. Nausea/Vomit 2. Constipation 3. Somnolence

Psychostimulants i.e. c__, d__ and m__ are used in the management of sedation and cognitive dysfunction in opioids.

1. caffeine 2. dextroamphetamine 3. methylphenidate

Myoclonus caused by opioids can be managed using __ and __. Pruritis can be managed using antihistamines but we should avoid __ i.e. cetirizine.

1. clonazepam 2. anti-convulsants 3. the sedating ones

There are 3 strategies for treating adverse effects from opioids: • Dose reduction (using __) • Changing to a different __ • __ management

1. adjuvants 2. opioid or route of administration 3. Symptomatic

``` Monitor the following for patients on opioid therapy: • Pain relief • Side effects • __ (physical and psychosocial) • __ behaviors ```

1. Function | 2. Drug related

Psuedo-addiction and addiction both lead to aberrant drug-related behaviour. However, pseudo-addiction is caused by __ and is reduced __. As the 2 can co-exist, knowing the patient well and __ are critical factors in distinguishing them.

1. uncontrolled pain 2. using improved pain control 3. having a good history

Addiction is unlikely to be due to pain management and is more commonly due to patients __. For such patients, __ can be drawn up to help reduce opioid abuse.

1. having a history of addiction and substance abuse | 2. opioid contracts

What are the two types of tolerance?

1. tolerance to SE is desirable | 2. tolerance to analgesia is *seldom*

tolerance does not cause ________

addiction

Pain management Flashcards

(114 cards)