Meperidine

Pain Relief

Meperidine is used to treat moderate to severe pain that is not well-controlled by other types of pain relievers. It is an opioid analgesic that works by altering the way the nervous system processes pain signals.

Surgical and Procedural Use

Healthcare providers may use meperidine in a hospital or clinical setting for the following reasons:

• Before surgery: To help patients relax and reduce anxiety before a procedure.
• During surgery: To assist with anesthesia and manage pain during a medical operation.
• After surgery: To control acute pain during the recovery period.

Obstetrical Use

Meperidine is sometimes used to provide pain relief for women during labor. It is typically intended for short-term use rather than for the treatment of long-term or chronic pain.

Mechanism of Action

Meperidine belongs to a class of drugs known as opioid analgesics, often referred to as narcotics. It works by acting directly on the central nervous system to provide relief from moderate to severe pain.

Interaction with the Nervous System

The medication functions by binding to specific proteins called opioid receptors. These receptors are found in the brain, spinal cord, and other parts of the body. When meperidine attaches to these receptors, it triggers several effects:

• Pain Signal Interference: It blocks or reduces the intensity of pain signals sent from the body to the brain.
• Altered Perception: It changes the way the brain interprets and reacts to pain, making the sensation more tolerable.
• Central Nervous System Depression: It slows down certain functions of the nervous system, which can lead to feelings of calmness or drowsiness.

While meperidine is effective at managing the sensation of pain, it does not treat the underlying physical cause of the pain itself.

Common Side Effects

• Dizziness or lightheadedness
• Nausea and vomiting
• Drowsiness
• Sweating
• Dry mouth
• Constipation
• Headache
• Changes in mood

Serious Side Effects

Seek immediate medical attention if you experience any of the following serious symptoms:

• Slowed, shallow, or stopped breathing
• Extreme sleepiness or difficulty waking up
• Seizures
• Confusion, agitation, or hallucinations
• Fast or pounding heartbeat
• Severe muscle stiffness, twitching, or loss of coordination
• Fainting
• Difficulty urinating
• Chest pain

A severe allergic reaction is possible. Seek emergency help for symptoms such as a rash, hives, swelling of the face, lips, or throat, or difficulty breathing.

Meperidine can also contribute to a serious condition called serotonin syndrome, particularly when used with other drugs. Symptoms may include shivering, sweating, fever, and diarrhea.

Boxed Warnings

Meperidine carries several boxed warnings due to serious safety risks:

• Addiction and Misuse: This medication has a high potential for addiction, abuse, and misuse, which can lead to overdose and death.
• Respiratory Depression: Serious or fatal breathing problems can occur, particularly when starting the medication or after a dose increase.
• Accidental Ingestion: Even a single accidental dose, especially by a child, can be fatal.
• Neonatal Opioid Withdrawal: Prolonged use during pregnancy can cause life-threatening withdrawal symptoms in the newborn.
• Interactions with Other Drugs: Using meperidine with benzodiazepines, alcohol, or other central nervous system depressants can cause extreme sedation, respiratory failure, coma, and death.

Seizure Risk and Toxicity

Meperidine is not recommended for chronic pain management. When used for more than a few days or in high doses, a byproduct called normeperidine can build up in the body. This buildup can cause central nervous system irritation, tremors, and seizures. This risk is significantly higher in individuals with kidney disease.

Contraindications

Meperidine should not be used in individuals with:

• Severe breathing problems, such as acute asthma or significant respiratory depression in unmonitored settings.
• A known or suspected blockage in the stomach or intestines, including paralytic ileus.
• A history of hypersensitivity to meperidine.
• Recent use of Monoamine Oxidase Inhibitors (MAOIs) within the last 14 days, as this can cause unpredictable and potentially fatal reactions.

Additional Precautions

Serotonin Syndrome: A potentially life-threatening condition called serotonin syndrome may occur when meperidine is taken with certain antidepressants or other serotonergic drugs. Symptoms may include agitation, hallucinations, rapid heartbeat, and muscle stiffness.

Low Blood Pressure: Meperidine may cause severe hypotension (low blood pressure), which can lead to dizziness or fainting, especially when standing up quickly.

Adrenal Insufficiency: Cases of adrenal insufficiency have been reported with opioid use, usually after more than one month of use. This condition occurs when the adrenal glands do not produce enough cortisol.

Head Injury: Meperidine may increase the pressure of the fluid in the brain and should be used with extreme caution in people with head injuries or increased intracranial pressure.

Pregnancy

Using meperidine during pregnancy may cause the baby to become physically dependent on the medication. This can lead to neonatal opioid withdrawal syndrome (NOWS) after birth, which may be life-threatening if not recognized and treated. Symptoms of withdrawal in a newborn can include irritability, excessive crying, tremors, vomiting, diarrhea, and difficulty gaining weight.

If meperidine is used during labor or delivery, it can cause breathing problems (respiratory depression) in the newborn. Healthcare providers typically monitor the baby closely if the mother received this medication shortly before birth.

Breastfeeding

Meperidine passes into breast milk and can affect a nursing infant. Potential side effects for the baby include:

• Extreme sleepiness or difficulty waking up
• Difficulty breastfeeding
• Breathing problems
• Limpness

Because of these risks, it is important to talk to a doctor about whether to continue breastfeeding while using meperidine. If breastfeeding, the infant should be monitored closely for any unusual signs or symptoms.

Oral Forms

Meperidine is available as an oral medication in the following forms:

• Tablets
• Oral solution

Injectable Forms

Meperidine is available as a solution for injection, which is typically administered by a healthcare provider. It can be given through several routes:

• Intravenous injection
• Intramuscular injection
• Subcutaneous injection

A combination product containing both meperidine and promethazine is also available as an injection for use in clinical settings.

FDA Approval and Indications

Meperidine is approved by the U.S. Food and Drug Administration (FDA) for the management of pain severe enough to require an opioid analgesic and for which alternative treatments are inadequate or not tolerated. It is also indicated for preoperative medication, support of anesthesia, and obstetrical analgesia.

Boxed Warnings

The FDA requires a boxed warning for meperidine due to serious safety risks. These include:

• Addiction, Abuse, and Misuse: Meperidine carries risks of addiction and misuse, which can lead to overdose and death.
• Respiratory Depression: Fatal respiratory depression may occur, requiring close monitoring, especially when starting the medication or increasing the dose.
• Accidental Ingestion: Ingestion of even one dose, particularly by children, can result in a fatal overdose.
• Neonatal Opioid Withdrawal Syndrome: Long-term use during pregnancy can cause life-threatening withdrawal symptoms in newborns.
• Drug Interactions: Use with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, increases the risk of profound sedation, coma, and death.

Regulatory Classification

Meperidine is a Schedule II controlled substance. This designation is for drugs with a high potential for abuse and severe psychological or physical dependence. To manage these risks, the FDA requires an Opioid Analgesic Risk Evaluation and Mitigation Strategy (REMS) for meperidine products, which involves provider education and patient counseling.

Contraindications

The FDA has established specific contraindications for meperidine, most notably its use with monoamine oxidase inhibitors (MAOIs). It should not be used in patients currently taking MAOIs or who have taken them within the last 14 days due to the risk of severe, potentially fatal reactions.

Understanding Meperidine Withdrawal

If you have been using meperidine for a long time or in high doses, your body may become physically dependent on it. Stopping the medication abruptly can trigger withdrawal symptoms. To prevent this, your healthcare provider will usually lower your dose gradually over time.

Common Withdrawal Symptoms

Withdrawal symptoms can range from mild to severe and may include:

• Restlessness, anxiety, or irritability
• Difficulty falling or staying asleep
• Sweating, chills, or goosebumps
• Watery eyes and a runny nose
• Frequent yawning
• Muscle, back, or joint pain
• Stomach cramps, nausea, vomiting, or diarrhea
• Increased heart rate and blood pressure
• Rapid breathing
• Dilated pupils

It is important not to stop taking meperidine without first consulting your doctor. They will create a tapering schedule to help your body adjust safely and minimize these effects.