Morphine causes a wide range of side-effects. However, severe reactions such as respiratory depressions and pronounced hypotension are uncommon when the drug is used therapeutically. Drop in blood pressure due to a cardiac infarction or hypovolemia can have dangerous results.

Constipation is the most important problem in long-term treatment. Somnolence and nausea are often only initially disturbing.

Even therapeutic doses can reduce respiratory frequency and can cause oliguria or urinary retention. Further potential side-effects are euphoria and dysphoria, anxiety, pruritus, urticaria, bronchospasms, spasms of the sphincter oddi, iedemas, headaches and miosis. Development of tolerance entails ever-increasing doses.

Morphine: Interactions

The effect of morphine is reinforced by other depressors of the central nervous system (psychotropic drugs, alcohol) as well as by the enzyme inhibitor cimetidine. Combined with muscle relaxants (anesthesia!) there is an increased respiratory risk.

Table of Contents | Indications | Pharmacology | Contraindications & Cautions | Risk Groups | References