16 precautions for using Amiodarone
Amiodarone is a popular drug, safe and effective, seemingly neither curing illnesses nor killing people. Today, let’s take a look at how amiodarone got into legal trouble.
Amiodarone seems simple to use: 150 mg (15 mg/min) for the first 10 minutes, 360 mg (1 mg/min) for the next 6 hours, and 540 mg (0.5 mg/min) for the remaining 18 hours. The daily oral and intravenous doses should not exceed 1200 mg. Everyone who uses it says it works well.
Is that so? Let’s take a look at how amiodarone got into legal trouble!
A 60-year-old female patient with a 5-year history of rheumatic heart disease was admitted to the hospital with recurrent palpitations for 3 days, fatigue, poor appetite, lower limb edema, and electrocardiogram showing atrial fibrillation (an unoriginal case). She was given 150 mg of amiodarone in 20 ml of normal saline slowly intravenously, then 300 mg in 50 ml of normal saline via a microinjector at 5 ml/h for 6 hours and then 2.5 ml/h.
A patient died after taking amiodarone. What went wrong in getting into a lawsuit? Let’s find out:
Note 1:
Amiodarone is both a cardioversion drug and a heart rate maintenance drug. So, can atrial fibrillation last for more than 48 hours be directly cardioverted? The patient was cardioverted, but suffered a cerebral embolism and died.
Atrial fibrillation is a common heart rhythm disorder that mostly occurs in patients with heart disease, such as rheumatic heart disease, coronary heart disease and hypertension.
In chronic atrial fibrillation, mural thrombi often form within the atrium, and their detachment can cause arterial embolism. Atrial fibrillation is one of the leading causes of thromboembolic events, with 75% of patients experiencing cerebrovascular accidents.
Note 2:
Can amiodarone be added to normal saline? No! Amiodarone hydrochloride injection must be prepared with 5% glucose solution (isotonic) and is not recommended for preparation with normal saline.
First, amiodarone is a diiodide substituted on the benzene ring. Generally speaking, iodine substituted compounds are unstable and prone to spontaneous deiodination and degradation. A slightly acidic environment can inhibit the degradation of amiodarone.
Secondly, the chloride ions in the NaCl solution replace the iodine on the benzene ring, resulting in precipitation. If prepared with normal saline, precipitation can be seen, which can have serious consequences when injected intravenously. Therefore, when amiodarone injection is used clinically, it should be prepared with 5% glucose.
Note 3:
After the patient took the medicine, the electrolyte test results came out, showing hypokalemia , which induced ventricular fibrillation.
When using amiodarone, the occurrence of hypokalemia must be prevented (and corrected): the QT interval should be monitored, and if ” torsade de pointes ” occurs, antiarrhythmic drugs should not be used (ventricular pacing should be given, and intravenous magnesium can be given).
Note a4:
Looking at the original electrocardiogram, QTC was significantly prolonged, inducing ventricular fibrillation.
Amiodarone can cause arrhythmias, sometimes fatal. Distinguishing between arrhythmogenic effects and ineffectiveness, which may manifest as worsening cardiac conditions, is important but difficult. Amiodarone blood levels should be monitored whenever possible. The effective blood concentration of amiodarone is 1 to 2.5 μg/mL, while the toxic blood concentration is 1.8 to 3.7 μg/mL or higher.
Reports of proarrhythmic effects of amiodarone are rarer than with other antiarrhythmic drugs and usually occur in the context of drug interactions and/or electrolyte disturbances.
Note 5:
Looking at the original electrocardiogram , preexcitation syndrome was combined with atrial fibrillation. At least, it is not suitable to use for preexcitation and atrial fibrillation. The guidelines recommend procainamide.
If the diagnosis of rapid ventricular fibrillation with preexcitation syndrome is confirmed, radiofrequency ablation is recommended . This is a minimally invasive procedure that does not require surgery and has a success rate of around 95%. Medication is less effective and carries greater risks.
Note 6:
The patient already had heart failure, and it got worse after taking it.
Intravenous administration is contraindicated in patients with hypotension, severe respiratory failure, cardiomyopathy, or heart failure (it may worsen the condition).
Note 7:
His blood pressure was already low, and he went into shock after using it.
Note 8:
The patient was advised to undergo radiofrequency surgery, but the surgery failed because the amiodarone had not been completely metabolized and was not suitable for radiofrequency surgery. The operation went wrong and the patient died on the operating table. The family came back to look for you.
Here are some more potential disputes:
Note 9:
For patients with hyperthyroidism, if they have hyperthyroidism and atrial fibrillation, be aware that amiodarone may cause hyperthyroid crisis .
Hyperthyroidism can occur after discontinuation of medication. In addition to exophthalmos, typical hyperthyroidism symptoms may appear, as may new arrhythmias. The incidence is approximately 2%, and it can completely resolve within weeks to months of discontinuation. A few patients may require treatment with antithyroid drugs, propranolol, or corticosteroids.
Note 10:
Patients with abnormal liver function died of liver failure.
Close monitoring of liver function (transaminases) is recommended at the start of treatment and periodically during treatment. Acute liver damage (including severe hepatocellular injury or liver failure, sometimes fatal) and chronic liver damage can occur within the first 24 hours of starting intravenous amiodarone. Therefore, if transaminases increase more than three times the normal value, the amiodarone dose should be reduced or discontinued.
Note 11:
If you are taking digoxin orally and do not reduce the dosage, it may easily cause digoxin poisoning.
Amiodarone can increase serum digoxin concentrations and may also increase the concentrations of other digitalis preparations to toxic levels. When starting this product, digitalis medications should be discontinued or reduced by 50%. If used together, serum drug concentrations should be carefully monitored. This product can enhance the inhibitory effects of digitalis drugs on the sinoatrial and atrioventricular nodes.
Note 12:
If you are currently using simvastatin without reducing the dose, it may cause myolysis .
The risk of muscle toxicity is increased when statins metabolized by CYP3A4, such as simvastatin, atorvastatin, and lovastatin, are co-administered with amiodarone.
Note 13:
Warfarin is currently being used without dose reduction, which may easily cause cerebral hemorrhage .
Amiodarone increases blood levels of anticoagulants, leading to an anticoagulant effect and increased risk of bleeding. Frequently monitor prothrombin levels and the international normalized ratio (INR). Adjust the dose of oral anticoagulants during and after amiodarone treatment.
Note 14:
Bradycardia, sinus arrest, cardiac arrest.
Amiodarone is contraindicated in patients with: sinus bradycardia and sinoatrial block, sinus node disease or high-grade atrioventricular conduction disorders, and those without an artificial pacemaker.
Note 15:
Acute respiratory distress syndrome in adults.
Very rare cases of interstitial pneumonia have been reported with intravenous amiodarone. Clinical manifestations include shortness of breath, dry cough, chest pain, restrictive changes in lung function, increased erythrocyte sedimentation rate, and elevated white blood cell counts. Severe cases can be fatal. Discontinuation of the drug and treatment with corticosteroids are necessary.
Note 16:
Severe peripheral phlebitis.
Local irritation during intravenous administration can cause phlebitis. Amiodarone should be administered via a central venous route whenever possible.
Therefore, there is no safe medicine in this world. The more we know about the rational use of medicines, the less likely we are to make mistakes.