Assess type, location, and intensity of pain prior to and 1 hr following PO, subcut, IM, and 20 min (peak) following IV administration. When titrating opioid doses, increases of 2550% should be administered until there is either a 50% reduction in the patient's pain rating on a numerical or visual analogue scale or the patient reports satisfactory pain relief. When titrating doses of short-acting morphine, a repeat dose can be safely administered at the time of the peak if previous dose is ineffective and side effects are minimal.
Patients on a continuous infusion should have additional bolus doses provided every 1530 min, as needed, for breakthrough pain. The bolus dose is usually set to the amount of drug infused each hour by continuous infusion.
Patients taking sustained-release morphine may require additional short-acting opioid doses for breakthrough pain. Doses of short-acting opioids should be equivalent to 1020% of 24 hr total and given every 2 hr as needed.
An equianalgesic chart (see Equianalgesic Dosing Guidelines) should be used when changing routes or when changing from one opioid to another.
High Alert: Assess level of consciousness, BP, pulse, and respirations before and periodically during administration. If respiratory rate is <10/min, assess level of sedation. Physical stimulation may be sufficient to prevent significant hypoventilation. Subsequent doses may need to be decreased by 2550%. Initial drowsiness will diminish with continued use.Geri: Assess geriatric patients frequently; older adults are more sensitive to the effects of opioid analgesics and may experience side effects and respiratory complications more frequently.Pedi: Assess pediatric patient frequently; children are more sensitive to the effects of opioid analgesics and may experience respiratory complications, excitability and restlessness more frequently.
Prolonged use may lead to physical and psychological dependence and tolerance. This should not prevent patient from receiving adequate analgesia. Most patients who receive morphine for pain do not develop psychological dependence. Progressively higher doses may be required to relieve pain with long-term therapy.
Assess bowel function routinely. Institute prevention of constipation with increased intake of fluids and bulk and with laxatives to minimize constipating effects. Administer stimulant laxatives routinely if opioid use exceeds 23 days, unless contraindicated.Lab Test Considerations
May ↑ plasma amylase and lipase levels.Toxicity and Overdose
If an opioid antagonist is required to reverse respiratory depression or coma, naloxone (Narcan) is the antidote. Dilute the 0.4-mg ampule of naloxone in 10 mL of 0.9% NaCl and administer 0.5 mL (0.02 mg) by direct IV push every 2 min. For children and adults weighing <40 kg, dilute 0.1 mg of naloxone in 10 mL of 0.9% NaCl for a concentration of 10 mcg/mL and administer 0.5 mcg/kg every 2 min. Titrate dose to avoid withdrawal, seizures, and severe pain.