Products
Morphine is available in many countries in various dosage forms, including tablets, capsules, oral suspension, syrup, morphine drops, suppositories, and injectables. It is also prepared in pharmacies as an extemporaneous formulation.
Structure and properties
Morphine (C17H19NO3, Mr = 285.3 g/mol) is present in drugs mainly as morphine hydrochloride and as morphine sulfate pentahydrate. These are white crystalline powders that are soluble in water. Morphine is a plant alkaloid found in the milky sap of the opium poppy. The dried milk sap is called opium.
Effects
Morphine (ATC N02AA01) has analgesic, cough-irritant psychotropic, depressant, and sedative properties. The effects are mainly due to binding to μ-opioid receptors.
Indications
- Moderate to severe acute and persistent pain or when non-opioid analgesics (WHO staging schedule) and/or weak opioids are insufficiently effective.
- Oral substitution treatment for opioid dependence (e.g., heroin), as part of medical, social, and psychological treatment. Not all drugs are approved for this indication.
Dosage
According to the professional information. Dosage depends on the dosage form.
Abuse
Morphine can be abused as a euphoric intoxicant. Therefore, its sale is strictly regulated and the drugs are subject to narcotics legislation.
Contraindications
- Hypersensitivity
- Craniocerebral trauma, increased intracranial pressure.
- Respiratory depression, obstructive airway disease.
- Acute abdomen, intestinal obstruction, delayed gastric emptying.
- Acute liver disease
- Concurrent therapy with MAO inhibitors
For complete precautions, see the drug label.
Interactions
Morphine is primarily conjugated in the liver by UGT2B7 to morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) and demethylated to normorphine. Morphine-6-glucuronide is an active metabolite. Interactions are possible with central depressant drugs, alcohol, other opioids, opioid antagonists, anticholinergics, cimetidine, diuretics, P-gp inhibitors, and muscle relaxants, among others. Morphine should not be combined with MAO inhibitors.
Adverse effects
The most common possible adverse effects include constipation, nausea, vomiting, dry mouth, poor appetite, abdominal pain, sweating, rash, pruritus, dizziness, headache, dullness, and fatigue. Morphine can cause respiratory paralysis (respiratory depression), low blood pressure, circulatory failure, and coma in an overdose. Opioid antagonists are administered as antidotes. Morphine can be physically and psychologically addictive and cause withdrawal symptoms if discontinued rapidly.
