1
Synera™ (lidocaine 70 mg and tetracaine 70 mg) topical patch
DESCRIPTION
Synera™ consists of a thin, uniform layer of a local anesthetic
formulation with an integrated, oxygen-activated heating
component that is intended to enhance the delivery of the local
anesthetic. The drug formulation is an emulsion in which the oil
phase is a eutectic mixture of lidocaine 70 mg and tetracaine 70 mg.
The eutectic mixture has a melting point below room temperature
and therefore exists as a liquid oil rather than as crystals. The
surface area of the entire Synera patch is approximately 50 cm2, 10
cm2 of which is active.
Lidocaine is chemically designated as acetamide, 2-
(diethylamino)-N-(2,6-dimethylphenyl), has an octanol:water
partition ratio of 182 at pH 7.3 and has the following structure:
Tetracaine is chemically designated as 2-(dimethylamino)ethyl p-
(butylamino)benzoate, has an octanol:water partition ratio of 5370
at pH 7.3 and has the following structure:
Each Synera patch contains lidocaine 70 mg and tetracaine 70 mg
in a eutectic mixture. The Synera formulation also contains the
following inactive ingredients: polyvinyl alcohol, sorbitan
monopalmitate, water, methylparaben and propylparaben.
The Synera heating component generates a mild warming that is
intended to enhance the delivery of the local anesthetic. Synera
begins to heat once the patch is removed from the pouch and is
CH3
NHCOCH2N(C2H5)2
CH3
COOCH2CH2N(CH3)2 CH3(CH2)3NH
2
exposed to oxygen in the air. Although the patch may increase
skin temperature by up to approximately 5ºC, maximum skin
temperature will not exceed 40ºC. The heating component is
composed of iron powder, activated carbon, sodium chloride,
wood flour, water and filter paper.
CLINICAL PHARMACOLOGY
Mechanism of Action: Synera™ applied to intact skin provides
local dermal analgesia by the release of lidocaine and tetracaine
from the patch into the skin. Lidocaine is an amide-type local
anesthetic agent and tetracaine is an ester-type local anesthetic
agent. Both lidocaine and tetracaine block sodium ion channels
required for the initiation and conduction of neuronal impulses,
resulting in local anesthesia.
Pharmacokinetics:
Absorption: The amount of lidocaine and tetracaine systemically
absorbed from Synera is thought to be directly related to the
duration of application. However, this was not clearly
demonstrated in clinical trials. Application of one Synera patch for
30 minutes in adults produced peak plasma concentrations of
lidocaine less than 5 ng/mL while plasma levels of tetracaine were
below the limit of quantitation (<0.9 ng/mL) in all subjects tested
(n = 12, see Table 1). Synera application up to 60 minutes did not
significantly increase plasma levels of lidocaine or tetracaine
compared to a 30-minute application.
Table 1
Absorption of Lidocaine and Tetracaine from Synera
Normal Adult Volunteers (n = 12)
Number of
Synera
Patches
Age Range
(yr)
Application
Time (min)
Drug Content
(mg)
Estimated
Amount
Absorbed
(mg) *
Cmax
(ng/mL)
Tmax
(hr)
1 18 - 65 30 Lidocaine, 70 1.7 1.7 1.7
Tetracaine, 70 1.6 < 0.9 na
*Estimated absorbed dose was calculated by subtracting the residual amount of
drug in each patch from the labeled claim.
na = not applicable
The surface area of application was 10 cm2 per Synera patch.
3
Application of Synera to broken or inflamed skin, or simultaneous
or sequential application of multiple Synera patches could result in
higher plasma levels of local anesthetic that could, in susceptible
individuals, produce systemic toxicity.
In general, application of multiple Synera patches either
simultaneously or sequentially is not recommended. However,
plasma levels of lidocaine and tetracaine have been determined in
clinical pharmacology studies following multiple successive and
simultaneous applications of Synera patches on intact skin.
Maximum plasma levels of lidocaine after the application of a)
four successive Synera patches for 30 minutes each with a 30-
minute interval between each patch application, and b) three
Synera patches for 60 minutes each with a 60-minute interval
between each application were less than 12 ng/mL and 8 ng/mL,
respectively. Tetracaine was not detected in plasma following
either treatment.
Simultaneous application of two or four Synera patches for 60
minutes produced peak plasma concentrations of lidocaine of less
than 9 ng/mL, while tetracaine plasma concentrations were not
detectable in all subjects (n=22). Sequential 30-minute
applications of four Synera patches at 60-minute intervals
produced peak plasma concentrations of lidocaine of less than 12
ng/mL, while tetracaine plasma concentrations were below the
limit of quantitation (n=11).
Distribution: When lidocaine is administered intravenously to
healthy volunteers, the steady-state volume of distribution is
approximately 0.8 to 1.3 L/kg. At lidocaine concentrations
observed following the recommended product application,
approximately 75% of lidocaine is bound to plasma proteins,
primarily alpha-1-acid glycoprotein. At much higher plasma
concentrations (1 to 4 mcg/mL of free base) the plasma protein
binding of lidocaine is concentration dependent. Lidocaine crosses
the placental and blood brain barriers, presumably by passive
diffusion. CNS toxicity may typically be observed around 5000
ng/mL of lidocaine; however a small number of patients reportedly
may show signs of toxicity at approximately 1000 ng/mL.
Volume of distribution and protein binding have not been
determined for tetracaine due to rapid hydrolysis in plasma.
Metabolism: It is not known if lidocaine or tetracaine is
metabolized in the skin. Lidocaine is metabolized rapidly by the
4
liver to a number of metabolites including
monoethylglycinexylidide (MEGX) and glycinexylidide (GX),
both of which have pharmacologic activity similar to, but less
potent than that of lidocaine. The major metabolic pathway of
lidocaine, sequential N-deethylation to monoethylglycinexylidide
(MEGX) and glycinexylidide (GX), is primarily mediated by
CYP1A2 with a minor role of CYP3A4. The metabolite, 2,6-
xylidine, has unknown pharmacologic activity. Following
intravenous administration of lidocaine, MEGX and GX
concentrations in serum range from 11% to 36% and from 5% to
11% of lidocaine concentrations, respectively. Serum
concentrations of MEGX were about one-third the serum lidocaine
concentrations.
Tetracaine undergoes rapid hydrolysis by plasma esterases.
Primary metabolites of tetracaine include para-aminobenzoic acid
and diethylaminoethanol, both of which have an unspecified
activity.
Elimination: The half- life of lidocaine elimination from the
plasma following intravenous administration is approximately
1.8 hr. Lidocaine and its metabolites are excreted by the kidneys.
More than 98% of an absorbed dose of lidocaine can be recovered
in the urine as metabolites or parent drug. Less than 10% of
lidocaine is excreted unchanged in adults, and approximately 20%
is excreted unchanged in neonates. The systemic clearance is
approximately 8-10 mL/min/kg. During intravenous studies, the
elimination half- life of lidocaine was statistically significantly
longer in elderly patients (2.5 hours) than in younger patients (1.5
hours).
The half- life and clearance for tetracaine have not been established
for humans, but hydrolysis in the plasma is rapid.
Special Populations
Pediatrics: Application of one Synera patch for up to 30 minutes
in children 4 months to 12 years of age (n=18) produced maximum
peak plasma concentrations of lidocaine and tetracaine of
63 ng/mL and 65 ng/mL, respectively. Application of two Synera
patches for up to 30 minutes to children 4 months to 12 years of
age (n=19) produced peak lidocaine levels of up to 331 ng/mL and
tetracaine levels of less than 5 ng/mL.
Elderly: After application of one Synera patch for 20 minutes,
plasma levels of lidocaine and tetracaine were not detectable in
5
elderly subjects (> 65 years of age, mean 72.0 ±4.3 years, n=10).
After simultaneous application of two Synera patches for 60
minutes to elderly subjects (> 65 years of age, mean 69.5 ±3.7
years, n=12), the maximum peak lidocaine concentration was 6
ng/mL and tetracaine was not detectable. During intravenous
studies, the elimination half- life of lidocaine was statistically
significantly longer in elderly patients (2.5 hours) than in younger
patients (1.5 hours).
Cardiac, Renal and Hepatic Impairment: No specific
pharmacokinetic studies were conducted. The half- life of
lidocaine may be increased in cardiac or hepatic dysfunction.
There is no established half- life for tetracaine due to rapid
hydrolysis in the plasma.
CLINICAL STUDIES
SUPERFICIAL VENOUS ACCESS
Three randomized, double-blind, placebo controlled clinical trials
in adult and geriatric subjects evaluated the degree of dermal
analgesia upon venipuncture following a 20-minute treatment with
Synera™ or a placebo patch (patch with heating component but no
drug). In each trial, subjects received Synera on one arm and
placebo patch on the other. Less pain was reported following
Synera treatment compared to placebo in all three studies as
measured by a 100 mm visual analog scale (VAS). In the first
study in 21 subjects, median VAS scores for Synera and placebo
treatments were 1 and 9, respectively. In the second study in 40
subjects, median VAS scores were 5 and 28 for Synera and
placebo treatments, respective ly. In the third study, in 40 subjects
over the age of 65 years, median VAS scores for Synera and
placebo treatments were 8 and 14, respectively.
In a randomized, double-blind, placebo controlled study, 61
pediatric patients received either Synera or placebo for 20 minutes
prior to venipuncture or IV cannulation in the antecubital fossa or
dorsum of the hand. Subjects were stratified by age group (3 to 6
years and 7 to 17 years). Children in the younger group reported
less pain with Synera than with placebo, as rated using a six-point
Oucher pain scale with faces. Children in the older group rated
their pain using a different instrument; an eleven-point Oucher
pain scale that contained both faces and numbers. Pain scores in
the older children treated with Synera were not statistically
significantly different from pain scores in those treated with
placebo.
6
In a double-blind trial in 250 adults, subjects were randomized to
receive either Synera without heating element or intact, heated
Synera, prior to venipuncture. Less pain was reported following
treatment with the heated Synera compared to the non-heated patch.
Median VAS scores for the patch with the heating component and
without the heating component were 17 and 22, respectively.
SUPERFICIAL DERMATOLOGICAL PROCEDURES
In one randomized, double-blind, placebo controlled study, 94
adult subjects received either Synera or placebo patch for 30
minutes prior to a superficial dermatological procedure such as
superficial excision, shave biopsy or electrodessication. Less pain
was reported following Synera treatment compared to placebo.
Median VAS scores for Synera and placebo treatments were 5 and
31, respectively. In a similarly designed study in 74 subjects over
the age of 65 years, less pain was reported following Synera
treatment compared to placebo with median VAS scores for
Synera and placebo treatments of 10 and 23, respectively.
In a randomized, double-blind, placebo controlled study, 88
pediatric patients were stratified by age group (3 to 6 years and 7
to 17 years) to receive a 30-minute application of either Synera or
placebo, prior to lidocaine injection. In younger children who used
the Oucher pain scale with faces, those receiving Synera reported
less pain from lidocaine injection than those receiving placebo.
Older children used the numerical Oucher pain scale to report pain
intensity. There was no difference between treatments observed in
the older children.
INDICATIONS AND USAGE
Synera™ is indicated for use on intact skin to provide local dermal
analgesia for superficial venous access and superficial
dermatological procedures such as excision, electrodessication and
shave biopsy of skin lesions (see CLINICAL STUDIES section).
CONTRAINDICATIONS
Synera™ is contraindicated in patients with a known history of
sensitivity to lidocaine, tetracaine, or local anesthetics of the amide
or ester type. Synera is also contraindicated in patients with para-
aminobenzoic acid (PABA) hypersensitivity and in patients with a
known history of sensitivity to any other component of the product.
WARNINGS
Application of Synera™ (lidocaine 70 mg and tetracaine 70 mg)
topical patch for longer duration than recommended, or the
7
simultaneous or sequential application of multiple Synera patches,
could result in sufficient absorption of lidocaine and tetracaine to
result in serious adverse effects (see Overdosage).
Even a used Synera patch contains a large amount of lidocaine and
tetracaine (at least 90% of the initial amount). The potential exists
for a child or pet to suffer serious adverse effects from chewing or
ingesting a new or used Synera patch. It is important for patients
to store and dispose of Synera out of the reach of children and pets.
PRECAUTIONS
General: Synera™ should be used with caution in patients who
may be more sensitive to the systemic effects of lidocaine and
tetracaine including the acutely ill or debilitated.
Allergic or anaphylactoid reactions associated with lidocaine,
tetracaine, or other components of Synera can occur. They are
characterized by urticaria, angioedema, bronchospasm, and shock.
If an allergic reaction occurs, it should be managed by
conventional means.
Contact of Synera with the eyes should be avoided based on the
findings of severe eye irritation with the use of similar products in
animals. Also, the loss of protective reflexes may predispose to
corneal irritation and potential abrasion. If eye contact occurs,
immediately wash out the eye with water or saline and protect the
eye until sensation returns.
Synera is not recommended for use on mucous membranes or on
areas with a compromised skin barrier because these uses have not
been adequately studied. Application to broken or inflamed skin
may result in toxic blood concentrations of lidocaine and tetracaine
from increased absorption.
Patients with severe hepatic disease or pseudocholinesterase
deficiency, because of their inability to metabolize local
anesthetics normally, are at a greater risk of developing toxic
plasma concentrations of lidocaine and tetracaine.
Lidocaine has been shown to inhibit viral and bacterial growth.
The effect of Synera on intradermal injections of live vaccines has
not been determined.
The integrated heating component contains iron powder, therefore,
the Synera patch must be removed before a patient undergoes
magnetic resonance imaging.
8
Information for patients: Patients should be aware that topical
application of local anesthetics such as Synera may lead to
diminished or blocked sensation in the treated skin. For this
reason, patients should avoid inadvertent trauma to the treated
area. Such trauma can result from scratching or rubbing before
complete sensation has returned, or from exposure to extreme hot
or cold temperatures.
Drug Interactions:
Antiarrhythmic Drugs: Synera should be used with caution in
patients receiving Class I antiarrhythmic drugs (such as tocainide
and mexiletine) since the systemic toxic effects are thought to be
additive and potentially synergistic with lidocaine and tetracaine.
Local Anesthetics: When Synera is used concomitantly with other
products containing local anesthetic agents, the amount absorbed
from all formulations should be considered since the systemic
toxic effects are thought to be additive and potentially synergistic
with lidocaine and tetracaine.
Carcinogenesis, Mutagenesis, Impairment of Fertility:
Carcinogenesis: Long-term studies in animals have not been
performed to evaluate the carcinogenic potential of either lidocaine
or tetracaine.
Mutagenesis : The mutagenic potential of lidocaine base and
tetracaine base has been determined in the in vitro Ames Bacterial
Reverse Mutation Assay, the in vitro chromosome aberration assay
using Chinese hamster ovary cells, and the in vivo mouse
micronucleus assay. Lidocaine was negative in all three assays.
Tetracaine was negative in the in vitro Ames assay and the in vivo
mouse micronucleus assay. In the in vitro chromosome aberration
assay, tetracaine was negative in the absence of metabolic
activation, and equivocal in the presence of metabolic activation.
Impairment of Fertility: Lidocaine did not affect fertility in
female rats when given via continuous subcutaneous infusion via
osmotic minipumps up to doses of 250 mg/kg/day (1500 mg/m2 or
43-fold higher than the single dermal administration [SDA]).
Although lidocaine treatment of male rats increased the copulatory
interval and led to a dose-related decreased homogenization
resistant sperm head count, daily sperm production, and
spermatogenic efficiency, the treatment did not affect overall
9
fertility in male rats when given subcutaneous doses up to 60
mg/kg (360 mg/m2 or 8-fold the SDA). Tetracaine did not affect
fertility in male or female rats when given subcutaneous doses up
to 7.5 mg/kg (45 mg/m2 or 1-fold the SDA). Multiples of exposure
are based on an SDA of 70 mg each of lidocaine and tetracaine in
Synera for 30 minutes to a 60 kg person (43 mg/m2).
Use in Pregnancy:
Teratogenic Effects: Pregnancy Category B. Lidocaine was not
teratogenic in rats given subcutaneous doses up to 60 mg/kg (360
mg/m2 or 8-fold the SDA) or in rabbits up to 15 mg/kg (180 mg/m2
or 4-fold the SDA). Tetracaine was not teratogenic in rats given
subcutaneous doses up to 10 mg/kg (60 mg/m2 or 1-fold the SDA)
or in rabbits up to 5 mg/kg (60 mg/m2 or 1-fold the SDA). Synera
components (lidocaine and tetracaine) given as a 1:1 eutectic
mixture was not teratogenic in rats (60 mg/m2 or 1-fold the SDA)
or rabbits (120 mg/m2 or 3-fold the SDA).
Nonteratogenic Effects: Lidocaine, contained 1:100,000
epinephrine, at a dose of 6 mg/kg (2-fold the SDA) injected into
the masseter muscle of the jaw or into the gum of the lower jaw of
Long-Evans hooded pregnant rats on gestation day 11 lead to
developmental delays in neonatal behavior among offspring.
Developmental delays were observed for negative geotaxis, static
righting reflex, visual discrimination response, sensitivity and
response to thermal and electrical shock stimuli, and water maze
acquisition. The developmental delays of the neonatal animals
were transient with responses becoming comparable to untreated
animals later in life. The clinical relevance of the animal data is
uncertain.
Pre- and postnatal maturational, behavioral, or reproductive
development was not affected by maternal subcutaneous
administration of tetracaine during gestation and lactation up to
doses of 7.5 mg/kg (45 mg/m2 or 1-fold the SDA).
No adequate and well-controlled studies have been conducted in
pregnant women. Because animal studies are not always
predictive of human response, Synera should be used during
pregnancy only if the potential benefit justifies risk to the fetus.
Labor and Delivery: Neither lidocaine nor tetracaine is
contraindicated in labor and delivery. In humans, the us
本文档为【Synera&#8482; (lidocaine 70 mg and tetracaine 70 mg) topical patch】,请使用软件OFFICE或WPS软件打开。作品中的文字与图均可以修改和编辑,
图片更改请在作品中右键图片并更换,文字修改请直接点击文字进行修改,也可以新增和删除文档中的内容。
该文档来自用户分享,如有侵权行为请发邮件ishare@vip.sina.com联系网站客服,我们会及时删除。
[版权声明] 本站所有资料为用户分享产生,若发现您的权利被侵害,请联系客服邮件isharekefu@iask.cn,我们尽快处理。
本作品所展示的图片、画像、字体、音乐的版权可能需版权方额外授权,请谨慎使用。
网站提供的党政主题相关内容(国旗、国徽、党徽..)目的在于配合国家政策宣传,仅限个人学习分享使用,禁止用于任何广告和商用目的。