Opium

As morphine has mutagenic propensity, it should be used for fertile women and men only if effective contraception is confirmed.

Opium alkaloids should not be used with other morphine agonists/antagonists (buprenorphine, nalbuphine, pentazocine) because of their competitive receptor-binding that may aggravate withdrawal symptoms and reduce therapeutic effect.

Cimetidine decreases the metabolism of morphine.

Opium alkaloids should not be used concomitantly with disulfiram or metronidazole. Both of these drugs can cause disulfiram-like reactions (flushing, rapid breathing, tachycardia).

Reduced consciousness and respiratory depression is potentiated by ethanol, hypnotics, general anaesthetics (e.g. barbiturates), MAO inhibitors and psychotropic drugs with a sedative action (e.g. fentiazines), gabapentin, antiemetic medications, antihistamines, and other opioids.

Administer at reduced doses and with the utmost caution to patients who are also being treated with other narcotic agents, sedatives, and tricyclic antidepressants and MAO-inhibitors.

Morphine’s duration of action may be reduced after taking fluoxetine.

Midazolam increases the analgesic effect of morphine and buprenorphine, and increases the respiratory depression effect of morphine. It is expected that midazolam will interact similarly with other opioids.

Rifampicin induces CYP 3A4 in the liver thus increasing the metabolism of morphine, codeine and methadone. The effect of these opioids is thereby decreased or counteracted.

Morphine inhibits the glucuronidation of zidovudine in vitro.

Opium alkaloids should be used with caution in the following conditions/for the following patients:

• Adrenocortical deficiency.
• Hypothyroidism.
• Low blood pressure with hypovolaemia.
• Pancreatitis.
• Prostatic hyperplasia and other conditions predisposing to urinary retention.

Opium alkaloids should be used with caution in the following conditions/for the following patients:

• Head injuries or increased intracranial pressure.
• Reduced consciousness.
• Heart failure secondary to lung disease.
• Cardiorespiratory shock.
• Monoamine oxidase inhibitors (including moclobemide), or within two weeks of their withdrawal.

Opium alkaloids should be used with caution in the following conditions/for the following patients:

• The elderly.
• Respiratory insufficiency (e.g. acute respiratory depression or Chronic Obstructive Airways Disease or asthma attack).
• Chronic renal disease and/or hepatic disease.
• Alcoholism.
• Biliary colic, cholelithiasis, biliary duct diseases.

Should be used with caution in pregnant women. Should not be used during the third trimester due to drowsiness and respiratory depression or withdrawal symptoms in the neonate.

Opium should not be used during breastfeeding, as opium passes into human milk. The milk to plasma concentration ratio is 1:4.

Fertility

As morphine has mutagenic propensity, it should be used for fertile women and men only if effective contraception is confirmed.

Due to its undesirable effects, opium may have a major influence on the ability to drive and use machines.

Cardiac disorders

Not known (cannot be estimated from the available data): Tachycardia, bradycardia

Nervous system disorders

Very common (≥1/10): Drowsiness

Common (≥1/100 to <1/10): Dizziness

Not known (cannot be estimated from the available data): Euphoria

Eye disorders

Common (≥1/100 to <1/10): Miosis

Respiratory, thoracic and mediastinal disorders

Common (≥1/100 to <1/10): Bronchospasms, cough decreased

Uncommon (≥1/1,000 to <1/100): Respiratory depression

Gastrointestinal disorders

Very common (≥1/10): Constipation, dry mouth

Common (≥1/100 to <1/10): Nausea, vomiting

Renal and urinary disorders

Common (≥1/100 to <1/10): Urinary retention

Uncommon (≥1/1,000 to <1/100): Urethral spasm

Skin and subcutaneous tissue disorders

Uncommon (≥1/1,000 to <1/100): Pruritus

Musculoskeletal and connective tissue disorders

Not known (cannot be estimated from the available data): Involuntary muscle contractions

Vascular disorders

Rare (≥1/10,000 to <1/1,000): Orthostatic hypotension

General disorders and administration site conditions

Common (≥1/100 to <1/10): Astenia

Hepatobiliary disorder

Uncommon (≥1/1,000 to <1/100): Hepatic enzymes increased