Adults:PO 10 to 30 mg every 4 h as needed. Avinza 45 to 120 mg once daily only in opioid-tolerant patients. Subcutaneous/IM 5 to 20 mg/70 kg every 4 h as needed. IV 2.5 to 15 mg per 70 kg in water for injection 4 to 5 mL over 5 min as needed. IV (open-heart surgery) 0.5 to 3 mg/kg. IV (MI pain) 8 to 15 mg; for very severe pain, additional smaller doses may be given every 3 to 4 h. PR 10 to 20 mg every 4 h as needed. Epidural Initial injection of 5 mg may provide pain relief for up to 24 h; if pain is not controlled within 1 h, give incremental doses of 1 to 2 mg. Do not exceed 10 mg per 24 h. Intrathecal Usual dose is 10% of epidural dose. Single injection of 0.2 to 1 mg may provide pain relief for 24 h. Do not inject more than 2 mL of 5 mg per 10 mL ampule or 1 mL of 10 mg per 10 mL ampule. Repeat injections not recommended.
Children:Subcutaneous/IM 0.1 to 0.2 mg/kg every 4 h.
Max dose: 15 mg.
Avinza must be swallowed whole; do not break, crush, chew, or dissolve).
If the patient cannot swallow the Avinza capsule whole, it may be opened and the contents sprinkled on a small amount of applesauce. Instruct the patient to swallow the applesauce mixture immediately and not to store for future use. Advise the patient that the applesauce mixture must not be chewed and the beads must not be crushed or dissolved due to the risk of acute overdose. Ingesting chewed or crushed Avinza beads will lead to the rapid release and absorption of a potentially toxic dose of morphine.
Relieves pain by stimulating opiate receptors in CNS;
Also causes respiratory depression, peripheral vasodilation, inhibition of intestinal peristalsis, sphincter of Oddi spasm, stimulation of chemoreceptors that cause vomiting and increased bladder tone.
Monitor for increased respiratory and CNS depression. Concomitant administration of cimetidine and morphine has been reported to precipitate apnea, confusion, and muscle twitching in an isolated report.
Clomipramine, nortriptyline, amitriptyline
Monitor for increased CNS and respiratory depression when administered with morphine.
Absorption: Variably absorbed (about 30%) following oral administration. More reliably absorbed from rectal, subcut, and IM sites. Following epidural administration, systemic absorption and absorption into the intrathecal space via the meninges occurs.
Distribution: Widely distributed. Crosses the placenta; enters breast milk in small amounts.
Protein Binding: Premature infants: <20%; Adults: 35%.
Metabolism/Excretion: Mostly metabolized by the liver. Active metabolites excreted renally.
Half-life: Premature neonates: 10–20 hr; Neonates: 7.6 hr; Infants 1–3 mo: 6.2 hr; Children 6 mo–2.5 yr: 2.9 hr; Children 3–6 yr: 1–2 hr; Children 6–19 yr with sickle cell disease: 1.3 hr; Adults: 2–4 hr.