Analgesic Adjunctive Agents (Coanalgesics) Flashcards Preview

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Flashcards in Analgesic Adjunctive Agents (Coanalgesics) Deck (13):
1

What are analgesic adjunctive agents?

Pharmacological agents which are useful in the management of pain but are not classified as analgesics
--can be used as monotherapy or in combination with non-opioids and opioids

2

The analgesic adjunctive agents include antidepressants, anticonvulsants, glucocorticoids and other drugs. Antidepresseants and anticonvulsants are the mainstay of treatment for a variety of neuropathic pain. First lets discuss the antidepressants, what are some features?

Serotonin and NE mediate descending inhibition of ascending pain pathways in the brain and spinal cord
--TCAs and SNRIs are used because they enhance both serotonin and NE transmission
SSRIs that enhance only serotonergic transmission are less effective analgesics

3

Lets discuss a little on the TCAs (tricyclic antidepressants), first off what are they?

Imipramine
Amitriptyline
Desipramine
Nortriptyline
(Again these are all SNRIs)

4

What types of pain can TCAs relieve?

Neuropathic pain including:
--diabetic, postherpetic, polyneuropathy, or nerve injury or fibromyalgia

5

What are the adverse effects of TCAs?

Constipation, Dry mouth, blurred vision, cognitive changes, tachycardia, urinary hesistation
---all associated with anticholinergic activity
Desipramine and Nortriptyline have fewer anticholinergic and sedative effects (so give to old ppl)

6

What are the warnings, precautions, and contraindications?

1. Angle-closure glaucoma
2. BPH
3. Urinary retention
4. Constipation
5. CVS (2nd or 3rd degree heart block, arrhythmias)
6. Impaired liver function

7

In addition to TCAs what are other SNRIs?

Venlafaxine and Duloxetine
--lack potent antihistamine, alpha adrenergic blocking, and anticholinergic effects
--used for several types of neuropathic pain
--better tolerated then TCAs

8

What are adverse effects of Venlafaxine and Duloxetine (SNRIs)?

Nausea
Sexual Dysfunction
Somnolence

9

Moving on to the Anticonvulsants, what are they?

Gabapentin
Pregabalin
Carbamazepine
---useful in management of neuropathic pain

10

First up in the anticonvulsants is Gabapentin and Pregabalin, what are some features?

Gabapentin: postherpetic neuralgia
Pregabalin: neuropathic pain associated with postherpetic neuraligia, diabetic neuropathy and fibromyalgia
MOA:
---block voltage gated calcium channels (this reduces release of glutamate, NE and substance P)
Adverse Effects:
--Dizziness, Somnolence and Peripheral Edema

11

Finally Carbamazepine is the third anticonvulsant, what are some features?

Drug of choice for trigeminal neuralgia
MOA:
--Blockage of voltage gated sodium channels (located in sensory neurons)
Adverse Effects:
--drowsiness, dizziness, nausea, vomiting
--leukopenia but is benign
--aplastic anemia is rare

12

Next drugs up that can be used as analgesic adjunctive agents are the glucocorticoids. What are some features?

Used in advanced illness
---acute nerve compression, ICP, bone pain, visceral pain, anorexia, nausea and depressed mood
Dexamethasone is the drug of choice: minimal mineralocorticoid effect
(prednisone and methylprednisolone can also be used)

13

Finally what are the other drugs that can be used as analgesic adjunctive agents?

1. Hydroxyzine: postoperative and cancer pain
2. Clonidine: improve pain and hyperalgesia in sympathetically maintained pain
3. Lidocaine: tx of posterherpatic neuralgia
4. Capsaicin: postherpetic neuralgia
5. Caffeine: enhance analgesic effect of acetaminophen and NSAIDs.

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