API

Morphine sulphate

Drug classification

Opioid analgesic (natural opiate).

Dosage form

Injection

API strength per dosage

10MG/ML

Dose

Adults: 10-30 mg every 4 hours as needed. Pediatrics: 0.1-0.2 mg/kg every 4 hours as needed. Adjust dose for renal impairment; avoid in severe hepatic impairment. Monitor closely for respiratory depression, especially in elderly or debilitated patients.

Mechanism of action

Binds primarily to μ-opioid receptors (MOR, encoded by OPRM1) in the central nervous system, acting as an agonist; inhibits adenylate cyclase, reduces cAMP, opens potassium channels, closes voltage-gated calcium channels, leading to neuronal hyperpolarization and decreased neurotransmitter release, resulting in analgesia and sedation.

Indications

Severe pain, acute pain, chronic pain, pain associated with myocardial infarction, pain in palliative care, preoperative medication, adjunct in anesthesia, pulmonary edema associated with left ventricular failure.

Side effects

Respiratory depression, sedation, constipation, nausea, vomiting, hypotension, bradycardia, pruritus, urinary retention, confusion, dizziness, miosis, dependence, tolerance, withdrawal symptoms.

Pregnancy category

Category C

Precautions

Respiratory depression, hypotension, head injury, acute alcoholism, renal or hepatic impairment, elderly or debilitated patients, pregnancy and breastfeeding, history of substance abuse, concurrent CNS depressants, adrenal insufficiency, biliary tract disorders, paralytic ileus, seizure disorders, abrupt discontinuation, increased intracranial pressure.

Contraindications

Respiratory depression, acute asthma, paralytic ileus, head injury with raised intracranial pressure, severe hepatic impairment, acute alcoholism, concurrent monoamine oxidase inhibitor use, hypersensitivity to morphine or excipients.