What Is Morphine (Morphine Hydrochloride)? FDA Approval, Licensing in Turkey, and Reimbursement

• FDA Approval: Yes (Initial approval date: 1941, for the first FDA-approved morphine sulfate formulations). Note: On January 27, 2010, the FDA formally approved morphine sulfate oral solution.
• Brand Name: Morfia tablets (the most widely available form in Turkey), MS Contin, Kadian, Avinza, Oramorph, Sevredol, and other generically marketed products
• Active Ingredient: Morphine Hydrochloride
• Routes of Administration: Oral tablets, oral solution, injection (IV/IM/SC), rectal suppositories, and extended-release capsules/tablets
• Class: Opioid analgesic
• Category: Pain reliever (analgesic), narcotic
• Manufacturers: Purdue Pharma, Hikma Pharmaceuticals, Teva, Mallinckrodt, Pfizer, and many generic manufacturers
• Availability in Turkey: Distribution through SGK-covered hospitals and pharmacies is restricted and controlled, with green or red prescriptions required. İlko İlaç, Galen İlaç, Gen İlaç, Osel İlaç
• Approved Cancer Indications: In advanced cancer, particularly metastatic disease or palliative treatment, it is widely used as a primary opioid option for managing moderate-to-severe chronic cancer-related pain.

What Is Morphine? How Does It Work?

Morphine is a potent opioid analgesic belonging to the opiate group. Medically, it is used to relieve moderate-to-severe pain. It is an alkaloid obtained naturally from the opium poppy (Papaver somniferum) and has a long history in modern medicine. Its effectiveness makes it a frequent choice for postoperative pain, cancer pain, trauma, chronic pain, and palliative care.

How Does It Work?

Morphine acts through opioid receptors in the central nervous system (CNS) and peripheral nervous system. These receptors are proteins that interact with endogenous opioids, such as endorphins and enkephalins, in the body's natural pain-control mechanisms. Morphine is a potent externally administered mimic of this system.

• Receptor Binding: Morphine binds with high affinity particularly to μ-opioid (mu) receptors. It also interacts, to a lesser extent, with δ (delta) and κ (kappa) opioid receptors.
• Suppression of Neuronal Transmission: After binding to its receptor, morphine reduces calcium entry into neurons and increases potassium efflux. This reduces neuronal electrical excitability, blocking transmission of pain signals.
• Altered Pain Perception: Morphine raises the pain threshold, making pain less noticeable, and reduces the emotional component of pain, easing the distressing sensation. By acting on emotional brain regions such as the limbic system, it also reduces pain-related restlessness and anxiety.

Common Questions About Morphine:

When Is Morphine Given to Patients With Cancer?

Morphine is generally used as a first-line opioid for moderate-to-severe or severe cancer pain that cannot be controlled with other medicines. It is widely used, particularly in advanced and metastatic disease.

Does Morphine Make You Sleepy?

Yes, morphine may have a sedative effect. Drowsiness, fatigue, and reduced attention are common adverse effects.

Is Morphine a Narcotic?

Morphine is a potent narcotic analgesic. When used medically, pain relief is its main effect. However, misuse can cause addiction, which is why it is a controlled medicine.

What Are Morphine's Adverse Effects?

The most common adverse effects are constipation, nausea, drowsiness, dizziness, itching, and respiratory depression. Tolerance and dependence may develop with prolonged use.

Can Morphine Cause Addiction?

The risk of addiction from morphine tablets and injections used for pain relief today is very low. Nevertheless, prolonged, uncontrolled use carries a risk of physical and psychological dependence. It should therefore be used only under medical supervision and on prescription.

What Is Morphine Used For?

Morphine is a powerful pain reliever, used particularly for cancer pain, postoperative pain, trauma, and chronic pain. It reduces both the physical and emotional components of pain.

In Which Situations Is Morphine Used?

Cancer pain, trauma such as fractures or burns, postoperative pain, myocardial infarction, labor pain, some heart failure settings, and palliative care.

FDA (US Food and Drug Administration) Approval History

• 1804: German pharmacist Friedrich Sertürner isolated morphine from opium. It was one of the first alkaloids obtained from plants.
• 1827: Merck began marketing morphine commercially.
• 1941: The US Food and Drug Administration (FDA) approved morphine sulfate tablets. This is the date morphine was formally approved by the FDA.
• January 27, 2010: The FDA approved morphine sulfate oral solution for treating moderate-to-severe acute and chronic pain.
• June 2, 2023: The FDA approved morphine sulfate oral solution and tablets for treating severe pain in adults and pediatric patients.

Licensing in Turkey

Morphine licensing in Turkey is overseen by the Ministry of Health's Turkish Medicines and Medical Devices Agency (TİTCK). It is licensed as a controlled medicine under the "green prescription" or "red prescription" system.

Therapeutic Indications

• Acute, severe pain: Fractures, dislocations, injuries, traumatic limb loss, crush injuries, burns, trauma, myocardial infarction, renal colic from kidney stones, and pain from penetrating ulcers.
• Cancer pain, metastatic carcinoma, and terminal illnesses: In these patients, morphine should be given regularly over a prolonged period.
• Postoperative pain: Helps patients mobilize early.
• Obstetric analgesia
• Orthopedic and diagnostic procedures
• Pulmonary edema and acute left ventricular failure: Morphine provides dramatic improvement by relieving fear and anxiety, reducing oxygen consumption, and redirecting blood from the congested lungs to the periphery. However, it should not be used for pulmonary edema caused by irritants.
• Preanesthetic medication: It should not be used unless there is a specific indication.
• Cardiovascular surgery: With inhalational anesthetics and intravenous administration, it has been reported to increase cardiac indices and central venous and pulmonary arterial pressures and to be usable in patients with minimal circulatory reserve.

Is It Reimbursed?

SGK reimbursement is available. Morfia is sold with a red prescription and can be obtained only on a physician's prescription.

Price: Morphine HCL 0.01 grams, 10 ampoules: 113.62 TL; Morphine 0.02 grams, 5 ampoules: 79.39 TL; Morfia 15 mg tablets: 239.88 TL; Morfia 30 mg tablets: 269.92 TL; Morfia 60 mg tablets: 252.85 TL

What Is Morfia?

Morfia is the most widely available oral morphine formulation in Turkey, accessible in hospitals and on prescription under SGK coverage. Its strong effect and controlled use make it important for improving quality of life, particularly in patients with cancer.

Morfia is indicated for moderate-to-severe acute and chronic pain. It is frequently used for palliation in cancer patients. As an opioid analgesic, it is available only on a physician's prescription within the red prescription system.

Initial dose: 15–30 mg every 4 hours

Mechanisms of Resistance

With prolonged morphine use, the body may develop tolerance, requiring progressively higher doses to achieve the same effect. Several mechanisms contribute to tolerance:

• A decrease in the number of opioid receptors
• Reduced receptor sensitivity
• Adaptation of signaling pathways
• Neuroplastic changes that reduce the central nervous system's response to the drug

In some clinical situations, such as neuropathic pain, opioids may also be less effective. This is a clinical example of pharmacological resistance.

Absorption

• Oral morphine is rapidly absorbed from the stomach and small intestine. However, it undergoes extensive first-pass metabolism in the liver, reducing its bioavailability.
• Oral bioavailability: Generally 20–40%.
• This loss does not occur with parenteral (injected) administration, producing a stronger, more rapid effect.

Distribution

• Morphine binds moderately to plasma proteins and distributes rapidly into body fluids. It readily enters well-perfused organs, particularly the brain, spinal cord, liver, kidneys, and intestines.
• Volume of distribution: Approximately 3–5 L/kg
• It can cross the blood-brain barrier, but more slowly than lipophilic opioids. Its onset is therefore later, but its effect lasts longer.

Metabolism

• Morphine is metabolized primarily in the liver.
• Enzyme system: UDP-glucuronyl transferase (UGT2B7)
• Two main metabolites are formed: Morphine-3-glucuronide (M3G), which has no analgesic effect and may have neurotoxic effects, and morphine-6-glucuronide (M6G), which has potent analgesic activity and contributes to morphine's effect. These metabolites may accumulate and cause toxicity, particularly in patients with impaired renal function.

Elimination

• Morphine and its metabolites are eliminated mainly through the kidneys in urine.
• More than 90% is excreted in urine within the first 24 hours.
• A small amount may pass through bile into feces.
• Half-life (t½): An average of 2–4 hours for oral formulations; longer with extended-release forms.
• The M6G metabolite has a longer half-life and a more persistent effect.

Dosing Schedule 

Oral, Short-Acting Formulations:

• Initial dose: 5–30 mg every 4 hours, adjusted according to pain
• Dose range: Generally 10–60 mg per dose
• Total daily dose: 60–360 mg, or more in opioid-tolerant patients
• Available in Turkey as Morfia 15 and Morfia 30 mg tablets. 

Oral, Extended-Release Formulations:

• Initial dose: 15–30 mg every 12 hours or 1 time daily (every 24 hours)
• Dose range: 15–200 mg/day, as a single or divided dose
• Titration is needed for chronic pain.
• Morfia CR is available in Turkey as 15, 30, 60, and 100 mg tablets in packs of 20. 

Injection (IV, IM, SC):

• 2–10 mg every 4 hours by slow IV infusion.
• The dose may be increased through titration.
• Intramuscular (IM) or subcutaneous (SC): 5–20 mg every 4 hours

Pediatric Doses:

• Calculated in mg per kilogram, for example 0.1–0.2 mg/kg.
• Dosing and monitoring in children require particular care.

Opioid-naive patients should start at a low dose, with gradual increases.

Higher doses may be required in tolerant patients.

Dose adjustment may be required in renal or hepatic impairment.

The starting dose is generally lower in older patients.

Drug Interactions

• Use With Central Nervous System Depressants: Morphine may cause synergistic respiratory depression with other sedatives. Slowed breathing, confusion, or coma may occur. Examples include benzodiazepines such as diazepam and lorazepam, barbiturates such as phenobarbital, antipsychotics, sleeping medicines such as zopiclone and zolpidem, and alcohol.
• Monoamine Oxidase Inhibitors (MAOIs): Concomitant use may cause severe sedation, hypotension, delirium, or even serotonin syndrome. Examples include selegiline and phenelzine. Morphine should not be started until at least 14 days after stopping an MAOI.
• CYP450 Enzyme Inducers or Inhibitors: Morphine is metabolized mainly by hepatic phase 2 enzymes (UGT2B7), but medicines affecting the CYP system indirectly may also interact. Ketoconazole and clarithromycin may increase morphine levels. Rifampin, carbamazepine, and phenytoin may reduce its effectiveness.
• Combination With Serotonergic Medicines: Morphine may indirectly increase serotonergic activity. Using it with medicines that raise serotonin levels may create a risk of serotonin syndrome. Examples include SSRIs such as fluoxetine and sertraline, SNRIs such as duloxetine, and tramadol.
• Interactions With Muscle Relaxants and Anticholinergics: When used with anticholinergic medicines, morphine may cause urinary retention, severe constipation, and gastrointestinal complications such as abdominal distension.
• Combination With Antihypertensive Medicines: Morphine may lower blood pressure through vasodilation. Concomitant diuretics and antihypertensives may increase the risk of hypotension.
• Naloxone and Other Opioid Antagonists: Agents such as naloxone and naltrexone rapidly and completely block morphine's effect. They are used in emergency overdose management but may precipitate withdrawal symptoms.
• All concomitant medicines should be reviewed carefully in patients receiving morphine. Combinations that may cause central nervous system depression should particularly be avoided, or doses adjusted.

Precautions

• Risk of Respiratory Depression: Morphine depresses the central nervous system. Respiratory depression may occur, particularly at high doses or in opioid-naive individuals. It should be used cautiously in respiratory conditions such as asthma, COPD, and sleep apnea.
• Sedation and Altered Consciousness: Fatigue, drowsiness, dizziness, and occasional confusion may occur. Medical approval should be obtained before driving, operating machinery, or performing other activities requiring alertness.
• Risk of Tolerance and Dependence: Prolonged use may cause physiological tolerance, requiring higher doses for the same effect. Psychological or physical dependence is also possible. Use without medical supervision is therefore strongly discouraged.
• Constipation: Morphine slows bowel movements and may cause severe constipation. Laxative support should be considered during treatment, with increased fluid and fiber intake.
• Renal and Hepatic Impairment: Because morphine and its active metabolites, particularly M6G, are renally eliminated, they may accumulate and cause toxicity in renal impairment. Metabolism may also slow in liver disease. Dose reduction or a change of medicine should be considered in these circumstances.
• Drug Interactions: With other depressants, such as benzodiazepines, alcohol, and antipsychotics, morphine may cause synergistically increased respiratory depression. Medicines affecting CYP enzymes may also increase or decrease its effect.
• Pregnancy and Breastfeeding: Morphine crosses the placenta and may cause fetal respiratory depression. Prolonged use may lead to neonatal withdrawal syndrome. Caution is needed during breastfeeding because morphine passes into breast milk.
• Older Patients: Morphine's effects may be more pronounced in older people. Start at a low dose and monitor patients closely.
• Headache and Psychogenic Pain: Morphine may be ineffective for pain of nonorganic origin, particularly chronic headaches, and carries an unnecessary risk of dependence. Its use for such pain should be assessed carefully.
• Risk of Overdose: Overdose may cause severe respiratory failure, hypotension, loss of consciousness, and death. Opioid antagonists such as naloxone should be used for emergency treatment.

Adverse Effects

• Constipation 40–90%
• Nausea 20–40%
• Vomiting 15–30%
• Drowsiness / sedation 20–60%
• Dizziness 10–20%
• Headache 5–15%
• Itching 5–15%
• Increased sweating 5–10%
• Difficulty urinating (urinary retention) 5–10%
• Dry mouth 10–20%
• Euphoria (a sense of pleasure) 5–15%
• Dysphoria (discomfort, restlessness) 1–5%
• Respiratory depression <5% (at high doses or in opioid-naive patients)
• Development of tolerance >50% (with prolonged use)
• Dependence and withdrawal symptoms <10% (may increase with dose and duration)
• Hypotension (low blood pressure) 5–10%
• Bradycardia (slow heart rate) <5%
• Altered consciousness / confusion 5–10% (particularly in older patients)
• Increased airway secretions <5%
• Miosis (constricted pupils) >80% (a classic opioid effect)
• Changes in hormone levels, such as reduced testosterone, 5–15%
• Leg restlessness / muscle spasms 1–5%
• Rare allergic reactions (urticaria, anaphylaxis) <1%