Many drugs used during the conduct of anesthesia are considered potential triggering agents for malignant hyperthermia (MH). Amide-type local anesthetics are not known to trigger this reaction. However, since the need for supplemental general anesthesia cannot be predicted in advance, it is suggested that a standard protocol for MH management should be available.
Reactions to ropivacaine are characteristic of those associated with other amide-type local anesthetics. A major cause of adverse reactions to this group of drugs may be associated with excessive plasma levels, which may be due to overdosage, unintentional intravascular injection or slow metabolic degradation.
The reported adverse events are derived from clinical studies conducted in the U.S. and other countries. The reference drug was usually bupivacaine. The studies used a variety of premedications, sedatives, and surgical procedures of varying length. A total of 3,988 patients have been exposed to ropivacaine hydrochloride injection at concentrations up to 1% in clinical trials. Each patient was counted once for each type of adverse event.
Because clinical trials are conducted under widely conditions, adverse reactions rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Incidence ≥ 5%
For the indications of epidural administration in surgery, cesarean section, postoperative pain management, peripheral nerve block, and local infiltration, the following treatment-emergent adverse events were reported with an incidence of ≥ 5% in all clinical studies (N=3988): hypotension (37%), nausea (24.8%), vomiting (11.6%), bradycardia (9.3%), fever (9.2%), pain (8%), postoperative complications (7.1%), anemia (6.1%), paresthesia (5.6%), headache (5.1%), pruritus (5.1%), and back pain (5%).
Incidence 1 to 5%
Urinary retention, dizziness, rigors, hypertension, tachycardia, anxiety, oliguria, hypoesthesia, chest pain, hypokalemia, dyspnea, cramps, and urinary tract infection.
Incidence in Controlled Clinical Trials
The reported adverse events are derived from controlled clinical studies with ropivacaine hydrochloride injection (concentrations ranged from 0.125% to 1% for ropivacaine hydrochloride injection and 0.25% to 0.75% for bupivacaine) in the U.S. and other countries involving 3,094 patients. Table 2 and Table 3 list adverse events (number and percentage) that occurred in at least 1% of ropivacaine hydrochloride injection-treated patients in these studies. The majority of patients receiving concentrations higher than 5 mg/mL (0.5%) were treated with ropivacaine hydrochloride injection.
Incidence <1%
The following adverse events were reported during the ropivacaine hydrochloride injection clinical program in more than one patient (N=3988), occurred at an overall incidence of <1%, and were considered relevant:
Application Site Reactions - injection site pain
Cardiovascular System - vasovagal reaction, syncope, postural hypotension, non-specific ECG abnormalities
Female Reproductive - poor progression of labor, uterine atony
Gastrointestinal System - fecal incontinence, tenesmus, neonatal vomiting
General and Other Disorders - hypothermia, malaise, asthenia, accident and/or injury
Hearing and Vestibular - tinnitus, hearing abnormalities
Heart Rate and Rhythm - extrasystoles, non-specific arrhythmias, atrial fibrillation
Nervous System - tremor, Horner's syndrome, paresis, dyskinesia, neuropathy, vertigo, coma, convulsion, hypokinesia, hypotonia, ptosis, stupor
Psychiatric Disorders - agitation, confusion, somnolence, nervousness, amnesia, hallucination, emotional lability, insomnia, nightmares
For the indication epidural anesthesia for surgery, the 15 most common adverse events were compared between different concentrations of ropivacaine hydrochloride injection and bupivacaine. Table 4 is based on data from trials in the U.S. and other countries where ropivacaine hydrochloride injection was administered as an epidural anesthetic for surgery.
Table 4 Common Events (Epidural Administration)
Using data from the same studies, the number (%) of patients experiencing hypotension is displayed by patient age, drug and concentration in Table 5. In Table 6, the adverse events for ropivacaine hydrochloride injection are broken down by gender.
Table 5 Effects of Age on Hypotension (Epidural Administration)
Total N: Ropivacaine Hydrochloride Injection = 760, Bupivacaine = 410
Table 6 Most Common Adverse Events by Gender (Epidural Administration)
The most commonly encountered acute adverse experiences that demand immediate countermeasures are related to the central nervous system and the cardiovascular system. These adverse experiences are generally dose-related and due to high plasma levels that may result from overdosage, rapid absorption from the injection site, diminished tolerance or from unintentional intravascular injection of the local anesthetic solution. In addition to systemic dose-related toxicity, unintentional subarachnoid injection of drug during the intended performance of lumbar epidural block or nerve blocks near the vertebral column (especially in the head and neck region) may result in underventilation or apnea ("Total or High Spinal"). Also, hypotension due to loss of sympathetic tone and respiratory paralysis or underventilation due to cephalad extension of the motor level of anesthesia may occur. This may lead to secondary cardiac arrest if untreated. Factors influencing plasma protein binding, such as acidosis, systemic diseases that alter protein production or competition with other drugs for protein binding sites, may diminish individual tolerance.
Epidural administration of ropivacaine hydrochloride injection has, in some cases, as with other local anesthetics, been associated with transient increases in temperature to > 38.5°C. This occurred more frequently at doses of ropivacaine hydrochloride injection > 16 mg/h.
Neurologic Reactions
These are characterized by excitation and/or depression. Restlessness, anxiety, dizziness, tinnitus, blurred vision or tremors may occur, possibly proceeding to convulsions. However, excitement may be transient or absent, with depression being the first manifestation of an adverse reaction. This may quickly be followed by drowsiness merging into unconsciousness and respiratory arrest. Other central nervous system effects may be nausea, vomiting, chills, and constriction of the pupils.
The incidence of convulsions associated with the use of local anesthetics varies with the route of administration and the total dose administered. In a survey of studies of epidural anesthesia, overt toxicity progressing to convulsions occurred in approximately 0.1% of local anesthetic administrations.
The incidence of adverse neurological reactions associated with the use of local anesthetics may be related to the total dose and concentration of local anesthetic administered and are also dependent upon the particular drug used, the route of administration, and the physical status of the patient. Many of these observations may be related to local anesthetic techniques, with or without a contribution from the drug. During lumbar epidural block, occasional unintentional penetration of the subarachnoid space by the catheter or needle may occur. Subsequent adverse effects may depend partially on the amount of drug administered intrathecally as well as the physiological and physical effects of a dural puncture. These observations may include spinal block of varying magnitude (including high or total spinal block), hypotension secondary to spinal block, urinary retention, loss of bladder and bowel control (fecal and urinary incontinence), and loss of perineal sensation and sexual function. Signs and symptoms of subarachnoid block typically start within 2 to 3 minutes of injection. Doses of 15 and 22.5 mg of ropivacaine hydrochloride injection resulted in sensory levels as high as T5 and T4, respectively. Analgesia started in the sacral dermatomes in 2 to 3 minutes and extended to the T10 level in 10 to 13 minutes and lasted for approximately 2 hours. Other neurological effects following unintentional subarachnoid administration during epidural anesthesia may include persistent anesthesia, paresthesia, weakness, paralysis of the lower extremities, and loss of sphincter control; all of which may have slow, incomplete or no recovery. Headache, septic meningitis, meningismus, slowing of labor, increased incidence of forceps delivery, or cranial nerve palsies due to traction on nerves from loss of cerebrospinal fluid have been reported [see Dosage and Administration (2.1)]. A high spinal is characterized by paralysis of the arms, loss of consciousness, respiratory paralysis and bradycardia.
Cardiovascular System Reactions
High doses or unintentional intravascular injection may lead to high plasma levels and related depression of the myocardium, decreased cardiac output, heart block, hypotension, bradycardia, ventricular arrhythmias, including ventricular tachycardia and ventricular fibrillation, and possibly cardiac arrest [see Warnings and Precautions (5.2) and Overdosage (10)].
Allergic Reactions
Allergic type reactions are rare and may occur as a result of sensitivity to the local anesthetic [see Warnings and Precautions (5.1)]. These reactions are characterized by signs such as urticaria, pruritus, erythema, angioneurotic edema (including laryngeal edema), tachycardia, sneezing, nausea, vomiting, dizziness, syncope, excessive sweating, elevated temperature, and possibly, anaphylactoid symptomatology (including severe hypotension). Cross-sensitivity among members of the amide-type local anesthetic group has been reported. The usefulness of screening for sensitivity has not been definitively established.