Pain

Question 1

Gabapentin

Answer 1

Analgesic adjunct, anticonvulsant, mood stabiliser

Dose- 100-300mg TDS

Nursing responsibility- monitor behaviour/worsening symptoms of suicide, assess efficacy for seizures/migraines/pain, may give false positive for protein in urine

Indications- partial seizures, postherpatic neuralgia, restless leg syndrome, neuropathic pain, migraine prevention, bipolar, anxiety, diabetic peripheral neuropathy

Action- unknown, May affect transport of amino acids across and stabilise neuronal membrane.

Contraindicated in hypersensitivity

Use cautiously in- renal impairment, may increase suicidal behaviour

Adverse reactions-
CNS- suicidal thoughts, depression, confusion, dizziness, drowsiness, sedation, anxiety, concentration difficulties (children), emotional lability (children), hostility, hyperkinesia, ataxia, altered reflexes, parasthesia, malaise, vertigo, weakness
CVS- hypertension
GI- weight gain, anorexia, flatulence, gingivitis
ENT- abnormal vision, nystagmus
Muscles- rhabdomyolysis, arthralgia, increased creative kinase
Misc- hypersensitive reactions

Interactions- antacids May reduce absorption, increased CNS depression with alcohol, opioids, antihistamines, sedatives/hypnotics

Natural products- Kava-kava, chamomile and valerian can increase CNS depression

Question 2

Pharmological effects from Opioids

Answer 2

CNS- analgesia, suppression of cough reflex, suppression of resp system, sedation and sleep, euphoria/dysphoria, miosis (pupil construction), nausea and vomiting, hypotension/bradycardia, tolerance or dependence
Peripheral- decrease gut motility, increased smooth muscle tone, spasms of sphincter muscles (can delay gastric emptying or cause urinary retention, biliary colic), release of histamine causing bronchoconstriction and severe itching

People with liver damage may accumulate active drug and sensitive to depressant effects (methadone better alternative). Renal disease extends half life and can cause resp depression

Morphine- protein bound=hydrophilic, crosses slowly into CNS, metabolites M3G, M6G excreted in kidneys

Fentanyl- lipophilic, rapid onset, short duration, metabolised by CYP3A in liver, metabolite is norfentanyl

Opioids- morphine, codeine, methadone, fentanyl, hydro morph , oxycodone, Pethidine, tramadol (opioid SNRI)

Question 3

Naloxone (opioid antagonist)

Answer 3

Blocks subjective and objective opioid effects, can precipitate withdrawal symptoms, displaces opioid analgesics from receptors

Question 4

Methylnatreone

Answer 4

Reversal of opioid induced constipation

Question 5

Buprenorphine

Answer 5

Opioid agonist