402
P A R T 4
Drugs acting on the central and peripheral nervous systems
control is determined by the relative ability of each
drug to cause physical dependence. Opioid agonists
include alfentanil (
Rapifen
), codeine (generic), dextro-
propoxyphene (
Doloxene
), fentanyl (
Actiq
,
Duragesic
,
Sublimaze
), hydromorphone (
Dilaudid
,
Jurnista
), meth-
adone (
Biodone
,
Physeptone
), morphine (
Anamorph
,
Sevredol
,
MS Contin
and others), oxycodone (
Endone
,
OxyContin
,
Oxynorm
,
Proladone
), pethidine (generic),
remifentanil (
Ultiva
), tapentadol (
Palexia SR
) (not avail-
able in New Zealand) and tramadol (
Durotram XR
,
Lodam
,
Tramal
and others).
Therapeutic actions and indications
The opioid agonists act at specific opioid receptor sites
in the CNS to produce analgesia, sedation and a sense of
well-being. These preparations are also used as antitus-
sives and as adjuncts to general anaesthesia to produce
rapid analgesia, sedation and respiratory depression.
Indications for opioid agonists include relief of severe
acute or chronic pain, preoperative medication, analgesia
during anaesthesia and specific individual indications,
depending on their receptor affinity. (See Table 26.1 for
usual indications for each opioid agonist.) Accurate cal-
culation of a dose is crucial to prevent overdosing.
In deciding which opioid to use in any particular sit-
uation, it is important to consider all of the aspects of
the person’s condition and to select the drug that will be
most effective in each situation with the fewest adverse
effects. Each person is different, and their response
to a drug is also different (Box 26.2). For instance, if
TABLE 26.1
DRUGS IN FOCUS Opioids
Drug name
Dosage/route
Usual indications
Opioid agonists (continued)
hydromorphone (Dilaudid,
Jurnista)
2–4 mg PO q 4–6 hours, or 3 mg PR q
6–8 hours, or 1–4 mg SC or IM q 4–6 hours
Relief of moderate to severe pain in adults
methadone (Biodone,
Physeptone)
5–10 mg SC, IM, PO q 6–8 hours
Relief of severe pain; detoxification and
temporary maintenance treatment of
opioid addiction in adults
morphine (Anamorph,
Kapanol, MS Contin)
Adult: 5–20 mg IM or SC or 15–30 mg PO q
4–6 hours
Paediatric: 0.1–0.2 mg/kg IM or SC
Relief of moderate to severe chronic
and acute pain; preoperatively and
postoperatively and during labour
oxycodone (OxyContin,
Oxynorm, Endone,
Proladone)
5–30 mg PO q 6 hours or 30 mg PR q
6–8 hours as needed
Relief of moderate to severe pain in adults
pethidine (generic)
Adult: 25–100 mg IM, SC or 25–50 mg slow IV
q 3–4 hours
Paediatric: 0.5–2 mg/kg IM or SC q 3–4 hours
Relief of moderate to severe pain,
preoperative analgesia and support of
anaesthesia, and obstetrical analgesia
remifentanil (Ultiva)
Adult and children >2 years: dose determined
by general anaesthetic being used
Analgesic for use during general
anaesthesia
Special considerations:
must be under
the direct supervision of anaesthesia
practitioner
tapentadol (Palexia SR)
Adult: 50 mg PO b.d.
Relief of moderate to severe chronic pain
tramadol (Durotram XR,
Lodam)
Adult: rapid relief of pain: 50-100 mg PO q
4–6 hours to a maximum 400 mg/day
Chronic pain: 25 mg/day PO titrated slowly to a
maximum 400 mg/day
Relief of moderate to moderately severe
pain
Special considerations:
limit use in
people with a history of addictions
Opioid agonists–antagonists
buprenorphine (Norspan,
Temgesic)
200–400 mcg SL q 6–8 hours, 300–600 mcg
IM or IV q 6–8 hours or 1 transdermal patch
every 7 days
Treatment of mild to moderate pain
Opioid antagonists
naloxone (Narcan)
Adult: 0.4–2 mg IV, IM or SC q 2–3 minutes as
needed
Paediatric: 0.01 mg/kg IV, IM or SC
Neonatal: 0.01 mg/kg IV, IM or SC q
2–3 minutes or 0.06 mg/kg IM immed at birth
Diagnosis of opioid overdose, reversal of
opioid effects
naltrexone (ReVia)
Adult: 50 mg/day PO
Adjunct treatment of alcohol or opioid
dependence in adults
