***Morphine

About 100 trade names, opioid analgesic,

Uses:

Moderate to severe pain, most effective in Nociceptive pain, severe breathlessness, acute pulmonary edema, cough, diarrhea

Pointers:

*Contraindications: Proven allergic to morphine & codeine. Nausea / vomiting / hallucinations are not a contraindication.

*Lower dosage in hepatic / renal failure.  Parenteral use avoid first pass metabolism. No ceiling dose but typical Morphine dose is < 200 mg /d. Oral to parenteral ratio is 3:1.  The SC dose is 1/3 of oral dose. Oral to rectal the dose is same 1:1. Kadian /Avinza long acting Opioids are bioequilanat (mg to mg same), open capsule sprinkle / tube but do not chew or crush or dissolve.

*Rifampin decreases morphine aborption, speeding up metabolism; additive with CNS depressants; prokinetic effects of Metoclopramide antagonized by opioids.

*Stimulate mu receptors, descending inhibitory & medulary center of the brain.

*oral onset 30 minutes; Peak: oral 1 hr; IM 30 minutes; SC 6 minutes; Duration oral / SC 4-5 hours

Side effects:

Constipation 90%. Nausea / vomiting: first few days up to 5, responds to Haloperidol, Metoclopramide. Dose / duration dependent sedation, drowsiness, dry mouth, dizziness visual accommodation problems. Rotating to another opioid if needed. Respiratory depression: rare, happens only with inappropriately large doses. Side effects occur in sequential manner: drowsiness, confusion, loss of consciousness before respiratory depression.  Keep sedation score of less than 2: 0=wide awake, 1=easily wakes up, 2=unable to stay awake, 3=difficult to arouse.  Opioid naïve: start low, go slow, start short acting opioid in smaller dosage 2.5 mg Morphine IR q 4 hrs titrated to effect. Sublingual morphine is most likely absorbed through GI rather than oral mucosa. Not a very good buccal nor sublingual medication. If use buccal use soluble tab or concentrated oral sol.

Supply:

IR tab 15, 30 mg;

liquid or concentrate 20 mg/ml ;

MS contin 15, 30, 60, 100 mg

inj 15 mg/ ml

Rx :

  1. Cough / breathlessness : start low 2.5-10 mg q 4 hrs
  2. Pain :  start low, go slow in opioid naïf patients
  3. opioids have no ceiling