Fentanyl Citrate Injection: Precautions, Usage and Dosage

fentanyl citrate injection, suitable for sedation and analgesia before, during and after anesthesia, is currently used in compound anesthesia.

  It is used for pre-anesthesia administration and induction of anesthesia and is used as an auxiliary medicine in combination with general anesthesia and local anesthetics for various operations. A mixture of 2.5 mg of Droperidol and 0.05 mg of this product, administered before anesthesia, can calm the patient and be indifferent to the external environment, but still, cooperate.

Pharmacology and toxicology

This product is a synthetic narcotic analgesic. The mechanism of analgesia is similar to that of morphine, which is an opioid receptor agonist, which is 60-80 times stronger than morphine. Compared with morphine and meperidine, this product has a rapid action, short duration of maintenance, does not release histamine, has little effect on cardiovascular function, and can inhibit the stress response during endotracheal intubation.

This product has a weaker inhibitory effect on breathing than morphine, but intravenous injection is too fast to inhibit breathing. Have addiction. Naloxone can antagonize the respiratory depression and analgesic effects of this product.
Acute toxicity LD50 (mg/kg): mouse, subcutaneous 62; vein 11.2.


Oral absorption through the gastrointestinal tract, but clinically, it is usually administered by injection. Intravenous injection takes effect in 1 minute, peaks in 4 minutes, and maintains for 30 to 60 minutes. Analgesia occurs in about 7 to 8 minutes during intramuscular injection and can be maintained for 1 to 2 hours.

The intramuscular injection had a bioavailability of 67%, a protein binding rate of 80%, and a T1/2 reduction of about 3.7 hours. This product is mainly metabolized in the liver, and metabolites and about 10% of the original drug are excreted by the kidneys.


This product is a potent analgesic, suitable for sedation and analgesia before, during and after anesthesia. It is a commonly used drug in compound anesthesia.

1. It is used for pre-anesthesia administration and induction of anesthesia and is used as an auxiliary medicine in combination with general anesthesia and local anesthetics for various operations. A mixture of 2.5 mg of droperidol and 0.05 mg of this product, administered before anesthesia, can make the patient quiet and indifferent to the external environment, but still can cooperate.

2. For all kinds of severe pain before, after and during surgery.


Adult intravenous injection

Initial amount during general anesthesia

1. minor surgery according to body weight 0.001 ~ 0.002mg / kg (based on fentanyl, the same below);

2. major operations according to body weight 0.002 ~ 0.004mg / kg;

3. During cardiopulmonary bypass, the total weight is calculated according to the body weight of 0.02-0.03mg/kg. The maintenance dose can be given half or continuous intravenous infusion every 30 to 60 minutes, generally 0.001-0.002mg/kg per hour.

4. general anesthesia while inhaling nitrous oxide according to body weight of 0.001 ~ 0.002mg / kg;

5. local anesthesia is not complete. As an auxiliary drug, the body weight is 0.0015 to 0.002 mg/kg.
Adult anesthesia before medication or postoperative analgesia
Intramuscular or intravenous injection of 0.0007 to 0.0015 mg/kg by weight.

Pediatric analgesia

There is no regulation under 2 years old, and the body weight is 0.002 to 0.003 mg/kg from 2 to 12 years old.

Analgesia after adult surgery

Epidural administration, the initial amount of 0.1mg, diluted with sodium chloride injection to 8ml, can be repeated every 2 to 4 hours, the maintenance amount is half of the initial amount.

Adverse reactions

1. General adverse reactions are dizziness, blurred vision, nausea, vomiting, hypotension, biliary sphincter spasm, throat, and sweating. Occasionally muscle twitching.

2. Severe side effects include respiratory depression, asphyxia, muscle stiffness, and bradycardia. If not treated promptly, respiratory arrest, circulatory arrest, and cardiac arrest may occur.

3. This product is addictive but lighter than pethidine.

Bronchial asthma, respiratory depression, patients who are particularly sensitive to this product, and patients with myasthenia gravis are banned. It is forbidden to use with monoamine oxidase inhibitors (such as phenelzine, penicillin, etc.).


1. This product is an anesthetic drug specially managed by the state. It must strictly abide by the state regulations on the management of narcotic drugs. The storage areas of hospitals and hospitals should be locked. The color of a prescription should be distinguished from other prescriptions. The responsible personnel at all levels shall abide by the handover system and shall not be slightly negligent.

2. This product must be administered for more than 14 days after the monoamine oxidase inhibitor (such as furazolidone, procarbazine), and should be tested with a small dose (1/4 of the usual amount), otherwise unpredictable and serious Complications, clinical manifestations of hyperhidrosis, muscle stiffness, blood pressure first rise and then drastic, respiratory depression, cyanosis, coma, high fever, convulsions, and eventually lead to collapse and death.

3. Arrhythmia, liver, kidney, dysfunction, chronic obstructive pulmonary disease, decreased respiratory reserve and brain trauma coma, increased intracranial pressure, brain tumors and other patients susceptible to respiratory depression should be used with caution.

4. This product has certain irritating properties, and should not be mistakenly inserted into the tracheobronchial or applied to the skin and mucous membranes.

5. When epidural injection of this product is analgesic, it usually takes 4 to 10 minutes to take effect. The concentration of cerebrospinal fluid reaches a peak in 20 minutes. At the same time, it can have generalized itching. The aging effect is 3.3 to 6.7 hours, and the respiratory rate is still slowed down. The possibility of tidal volume reduction should be timely.

6. This product is not a total anesthetic. Although a large number of rapid intravenous injections can make the mind disappear, the patient’s stress response still exists, often accompanied by intraoperative awareness.

7. Rapid bolus injection can cause muscle stiffness in the chest wall and abdominal wall and affect ventilation.
Pregnant women and lactating women
The safety of medication during pregnancy is still difficult to affirm and use with caution.

Elderly patients medication

The first dose of an elderly, infirm patient should be appropriately reduced, and the dose increase should be determined by the effect of the first dose.

medicine interactions

1. This product has similarities with pethidine due to its chemical structure, and the two drugs may be cross-sensitive.

2. This product has synergistic effects with central inhibitors such as hypnotic sedatives (barbiturates, diazepam, etc.), antipsychotics (such as phenothiazines), other anesthetic analgesics, and general anesthetics. Care should be taken when using it together and the dosage should be adjusted appropriately.

3. This product is combined with 80% nitrous oxide to induce heart rate slowing, weakened myocardial contraction, reduced cardiac output, and especially left the ventricular function.

4. The amount of muscle relaxant can be reduced by the use of this product. The muscle relaxant can relieve the muscle stiffness of this product, occasionally apnea, and the duration is long. It should be recognized that this is central (this product) Caused by use, or peripheral (because muscle relaxant acts on the N2 receptor at the neuromuscular junction).

5. Central inhibitors such as barbiturates, tranquilizers, anesthetics, have the effect of strengthening the product, such as combined application, the dose of this product should be reduced by 1/4 to 1/3.


Poisoning symptoms

High-dose rapid intravenous injection can cause neck, chest, and abdominal wall muscle rigidity, and reduced chest compliance affects ventilation function. Occasionally, heart rate slowdown, blood pressure drop, and pupil diminution may occur and finally may cause respiratory arrest, circulatory inhibition, or cardiac arrest.

Poisoning rescue

Those with muscle rigidity can be confronted with muscle relaxants or morphine antagonists (such as naloxone, acryl morphine, etc.). Immediately after the respiratory depression, first aid measures such as oxygen inhalation and artificial respiration may be used. If necessary, morphine specific antagonists may be used, intravenous naloxone 0.005-0.01 mg/kg, and adult 0.4 mg.

Patients with bradycardia can be treated with atropine. The hypotension caused by the combination of this product and droperidol can be treated by infusion, expansion and other measures. When it is ineffective, a booster can be used, when adrenaline is disabled.