Influence of Pre- and Intraoperative Local Anaesthetic in Strabismus Surgery under General Anaesthesia in Adults.

BACKGROUND: As studies have shown a reduction in the occurrence of the oculocardiac reflex with the addition of local anaesthesia, we changed our care regime accordingly a few years ago. To promote and establish better patient care, we retrospectively analysed the files of our patients who underwent strabismus surgery from 2013 to 2021 in order to compare strabismus surgery under general anaesthesia with and without local anaesthetics in a routine clinical setting. PATIENTS AND METHODS: Data from 238 adult patients who had undergone strabismus surgery could be extracted from the files: G1: n = 102, only general anaesthesia; G2: n = 136, preoperative application of tetracaine eye drops and intraoperative subtenon lidocaine/levobupivacaine in addition to general anaesthesia. We compared the two groups in regard to the frequency of oculocardiac reflex, the amount of atropine needed to treat, as well as the amount of antiemetic and analgesic medication given, and time spent in the recovery room. RESULTS: Mean age of G1 was 50 years and 52 years in G2. There was no significant difference between the kind of surgeries (recessions/resections), the number of patients who had undergone a reoperation, or the duration of the operations. Adding local anaesthetics resulted in significantly less occurrence of oculocardiac reflex (p = 0.009), a reduction in the need for atropine, analgesic, or antiemetic medication, as well as reduced time in the recovery room. CONCLUSION: As this increases patient safety and comfort and is cost-effective (less time in the recovery room), we recommend adding perioperative local anaesthesia to strabismus surgery performed under general anaesthesia.

Comparison of Proparacaine, Tetracaine, and Oxybuprocaine in Corneal Sensitivity Measurement.

Purpose: This study aimed to determine the onset and duration of action of 3 commercially available topical anesthetic solutions in Brazil, using the Cochet-Bonnet esthesiometer (Luneau®, Paris, France) and to quantitatively assess patient-reported discomfort during application. Methods: A prospective, randomized, masked, and double-blind study was conducted, involving 40 eyes from 21 patients. Patients were administered each one of the topical anesthetics weekly, and corneal sensitivity was measured using the Cochet-Bonnet esthesiometer's corneal touch threshold (CTT). Patients rated the burning sensation using a visual analogue scale (VAS). Results: Among the 21 patients (42.9% male), with a mean age of 31.95 years (±standard deviation = 10.17, range = 22.0-58.0), corneal sensitivity significantly decreased 30 s after application, returning to baseline after 30 min for all groups (P < 0.0001). Significant differences in CTT were observed at 5 min, with proparacaine exhibiting a superior anesthetic effect (P = 0.0003), at 10 min, where tetracaine displayed the most substantial anesthetic effect (P = 0.0135), and at 20 min, where tetracaine demonstrated the highest anesthetic efficacy (P < 0.0001). VAS scores indicated the most intense burning sensation with tetracaine (P < 0.0001). Men reported experiencing more discomfort during instillation compared with women (P = 0.0168). Conclusions: Proparacaine exhibited the fastest onset of action among the 3 topical anesthetics and provided a more comfortable eye sensation during instillation. However, tetracaine demonstrated the longest duration of action despite causing more discomfort.

Effect of superior laryngeal nerve block in alleviating sore throat after application of i-gel supraglottic airway: a randomized controlled trial.

BACKGROUND: Postoperative sore throat (POST) is a common complaint after supraglottic airway device (SAD) application. Internal branch of the superior laryngeal nerve (iSLN) block has the potential to alleviate POST. The aim of this trial was to explore the effect of iSLN block in alleviating sore throat, as well as to identify the potential risk factors for POST after SAD insertion. METHODS: One hundred thirty-four patients scheduled for elective gynecological surgery were randomized to either group T: tetracaine syrup (1%) for local lubrication on i-gel supraglottic device (n = 67) or group B: i-gel insertion with water based lubricant on it and followed by bilateral iSLN block (ropivacaine, 0.375%, 2 ml for each side) (n = 67). Under ultrasound guidance, iSLN was exposed below thyrohyoid membrane. The primary outcome was the intensity of sore throat at 6 h after surgery. In addition, POST score at 0.5 h and 24 h, the severity of postoperative swallowing discomfort, acoustic analysis and complications were measured. RESULTS: Compared with tetracaine syrup for local lubrication, iSLN block resulted in a reduced intensity of POST at 0.5 h (P = 0.044, OR = 1.99, 95%CI 1.02 to 3.88) and 6 h (P < 0.001, OR = 5.07, 95%CI 2.53 to 10.14) after surgery, as well as less severity of swallowing discomfort (P < 0.001, OR = 2.21, 95%CI 1.63 to 2.99) and cough (P = 0.039, OR = 1.97, 95%CI 1.04 to 3.73). The patients after iSLN block presented lower jitter and shimmer value in acoustic analysis at 6 h after surgery (P < 0.001). CONCLUSIONS: iSLN block was effective in alleviating POST, improving voice function, as well as reducing postoperative swallowing discomfort and coughing. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2000037974) on 8th Sept 2020.

Tetracaine hydrochloride induces cell cycle arrest in melanoma by downregulating hnRNPA1.

Recent evidence suggests potential benefits of applying local anesthetics in cancer patients. Specifically, tetracaine has a potent antitumor effect in diverse cancers, including neuroblastoma, breast cancer, and melanoma; however, the underlying molecular mechanisms remain unclear. Here, we reported that tetracaine hydrochloride inhibited the growth of melanoma cells and arrested melanoma cells in the G0/G1 phase. Tetracaine hydrochloride treatment resulted in translocation of hnRNPA1 from the nucleoplasm to the nuclear envelope and reduced the protein stability of hnRNPA1 possibly by disrupting the dynamic balance of ubiquitination and neddylation. Elevated hnRNPA1 upregulated cyclin D1 to promote cell cycle in melanoma. The hnRNPA1 overexpression attenuated the effect of tetracaine hydrochloride on melanoma cell growth suppression and cell cycle arrest. Furthermore, melanoma homograft experiments demonstrated that tetracaine hydrochloride suppressed melanoma growth, while hnRNPA1 overexpression alleviated tetracaine's antitumor effect on melanoma. Taken together, our findings suggest that tetracaine hydrochloride exerts a potent antitumor effect on melanoma both in vitro and in vivo, and the effect involves cell cycle arrest induction via downregulation of hnRNPA1.

Patch testing with aluminium Finn Chambers could give false-positive reactions in patients with contact allergy to aluminium.

BACKGROUND: Earlier laboratory studies have shown that sodium tetrachloropalladate, Myroxylon pereirae, caine mix II, and palladium chloride trigger the release of aluminium (Al) from Finn Chambers (FC). OBJECTIVES: To investigate whether aluminium realease from FC could influence the diagnostic outcome of patch testing with FC. METHOD: A retrospective analysis of patch test results from 2010 to 2019 was performed. A two-sided Fisher's exact test was used to calculate any overrepresentation of contact allergy to Al among patients with positive reactions to sodium tetrachloropalladate, Myroxylon pereirae, caine mix II, and palladium chloride. RESULTS: A total of 5446 patients had been tested with FC during the study period. There was a significant overrepresentation of contact allergy to Al among patients with positive reactions to sodium tetrachloropalladate, Myroxylon pereirae, caine mix II, and palladium chloride. Patients with a strong Al allergy had significantly higher amounts of concomitant reactions to sodium tetrachloropalladate, Myroxylon pereirae, caine mix II, and palladium chloride compared to patients with weak Al allergy. These results were not seen for patients tested with Finn Chambers AQUA. CONCLUSION: In patients with contact allergy to Al, patch testing with Finn chambers could give false-positive reactions to sodium tetrachloropalladate, Myroxylon pereirae, caine mix II, and palladium chloride.

Short-Term Topical Tetracaine Is Highly Efficacious for the Treatment of Pain Caused by Corneal Abrasions: A Double-Blind, Randomized Clinical Trial.

STUDY OBJECTIVE: The objective of this study is to show that patients with corneal abrasions would experience more pain relief with short-term topical tetracaine than placebo. METHODS: The study was a prospective, double-blind, randomized trial of tetracaine versus placebo set in the emergency department (ED). A total of 118 adults who presented with uncomplicated corneal abrasions were included and randomized. The intervention was either topical tetracaine or placebo applied every 30 minutes as needed for 24 hours. The primary outcome was the overall numeric rating scale pain score measured at the 24- to 48-hour ED follow-up examination. RESULTS: One hundred eleven patients were included in the final analysis, 56 in the tetracaine group and 55 in the placebo group. At the 24- to 48-hour follow-up, the overall numeric rating scale pain score after use of the study drops was significantly lower in the tetracaine group (1) versus placebo group (8) (Δ7; 95% confidence interval 6 to 8). Patients in the tetracaine group used less hydrocodone than those in the placebo group. The complication rates between the 2 groups were similar. CONCLUSION: Short-term topical tetracaine is an efficacious analgesic for acute corneal abrasions, is associated with less hydrocodone use compared with placebo, and was found to be safe in this sample.

Improving mucosal anesthesia for awake endotracheal intubation with a novel method: a prospective, assessor-blinded, randomized controlled trial.

BACKGROUND: Topical anesthesia is a crucial step in awake endotracheal intubation for providing favorable intubation conditions. The standard of care technique for awake intubation at our institution, which consists of oropharyngeal tetracaine spray, can result in inadequate mucosal anesthesia. Therefore, we sought to compare the effectiveness of dyclonine hydrochloride mucilage to the standard of care tetracaine in achieving anesthesia of the upper airways for awake endotracheal intubation. METHODS: This is a randomized, assessor-blinded, prospective study. From Jun. 1st, 2019 to Aug. 1st, 2019, patients scheduled for either endoscopic submucosal dissection or peroral endoscopic myotomy were enrolled and randomly allocated into two groups after obtaining written informed consent: patients allocated to novel awake intubation care (Group N-AIC) received a single administration of oral dyclonine hydrochloride mucilage, whereas patients allocated to standard awake intubation care (Group S-AIC) received three oropharyngeal tetracaine sprays before transcricoid tetracaine injection before awake intubation. Mean arterial pressure (MAP), which was the primary outcome of this study, as well as heart rate (HR) were recorded throughout the procedure and compared between the two groups. Feeling of numbness, nausea, and intubation conditions after topical anesthesia were also assessed. RESULTS: Sixty patients were enrolled and completed the study. Baseline MAP and HR were similar between the two groups. However, hemodynamic responses to intubation and gastrointestinal endoscopy, especially MAP, were significantly less elevated in Group N-AIC. The degree of numbness of the oropharyngeal mucosa after topical anesthesia did not differ between the two groups, neither did the feeling of nausea during laryngoscopy. The amount of pharyngeal secretions before intubation was less in Group N-AIC. Total intubation time was significantly shorter in Group N-AIC when compared to Group S-AIC (18.4 ± 2.86 vs. 22.3 ± 6.47, P < 0.05). Extubation bucking was significantly less frequent in Group N-AIC (13.3% vs. 76.7%). Patients received in Group N-AIC had a lower rate of post-extubation sore throat compared to Group S-AIC (6.7% vs. 43.3%). No adverse side effects attributable to either tetracaine or dyclonine were observed in this study. CONCLUSIONS: In awake endotracheal intubation, novel care using oral dyclonine hydrochloride mucilage can provide more favorable mucosal anesthesia and better intubation conditions compared to standard of care practice using oropharyngeal tetracaine spray. TRIAL REGISTRATION: ChiCTR1900023151 . Date of registration: May 14th, 2019.

Assessment of Factors Associated With Postoperative Pain After Photorefractive Keratectomy.

PURPOSE: To define the factors that affect patient's self-assessed postoperative pain after photorefractive keratectomy (PRK). METHODS: Patients who underwent PRK in 2016 were evaluated. Anonymized data collected included patient gender, age, and season at the time of surgery, ablation depth, surgeon status (attending vs. resident), topical tetracaine use, and subjective pain scores at postoperative days (PODs) 1 and 7. Average pain scores and amount of pain medication taken were analyzed for each of the previously mentioned variables. RESULTS: Overall, 231 patients who underwent PRK were analyzed. The mean pain score and SD were 0.78 ± 1.87 on POD 1 and 0.03 ± 0.37 by POD 7. Patients who used topical tetracaine reported significantly higher pain on POD 1 and 7 compared with patients who did not use tetracaine (P < 0.001 and P = 0.038, respectively). No significant differences in pain scores were seen based on surgeon status, ablation depth, gender, and season. Patients who used topical tetracaine took a higher amount of oral pain medication (9.44 ± 6.01) compared with those who did not (7.02 ± 4.71) (P = 0.022). CONCLUSIONS: Postoperative pain was significantly elevated in patients who used tetracaine on POD 1 and POD 7. These patients were also more likely to take oral pain medication than those who did not use topical tetracaine. Surgeon status, season, gender, and ablation depth showed no significant differences in subjective pain scores. Oral pain medication should be evaluated to assess efficacy and safety in inhibiting ocular pain after PRK.

Efficacy of lidocaine 7 %, tetracaine 7 % self-occlusive cream in reducing MAL-cPDT-associated pain in subjects with actinic keratosis: A randomized, single-blind, vehicle-controlled trial (The "3P-Trial").

INTRODUCTION: Conventional photodynamic therapy (cPDT) is considered a very effective treatment of actinic keratosis (AK) lesions. However, its use is limited by the fact that this procedure could be very painful. The use of topical anesthetics such as tetracaine or lignocaine/prilocaine has shown disappointing results in term of pain reduction. A self-occlusive topical 7% lidocaine/7% tetracaine anesthetic cream (LT-C) approved by the FDA to provide local topical anesthesia in adults undergoing superficial dermatological procedures is available. There are no data regarding its pain reducing effect during cPDT. We perform a prospective, randomized, single-blind, two-center trial (The 3P-Trial) to assess the pain reduction effect of LT-C versus vehicle in subjects with AK undergoing cPDT. MATERIAL AND METHODS: Fifty AK subjects (74 ± 10 years, 32 men, 18 women) with on average 17 lesions were enrolled after their written informed consent. Eight subjects presented also a total of 16 basal cell carcinoma lesions. Twenty-five were randomized to LT-cream, applied 1 h before the Methyl amino levulinate (MAL)-cPDT session and 25 to cream vehicle. The main outcome was the patient-assessed evaluation of pain score during and just after the conclusion of cPDT session (mean of the two values) using a 10-point visual analog scale (VAS). The cPDT session (LED Red light 630 nm) was performed with a duration of 6 ± 2 min with a standard fluence of 37 J/cm2. All treated lesions were prepared by gentle superficial curettage. RESULTS: All the randomized subjects concluded the trial. The mean ± SD of VAS score in vehicle group was 6.2 ± 2.7 (95 % CI of the mean: 5.0-7.5). In the group treated with LT-cream the VAS score was 3.3 ± 1.9 (95 % CI of the mean: 2.5-4.1). The active cream reduced the VAS score by 47 %. Median values of pain VAS score in the active group was reduced by 60 % in comparison with vehicle group (3.0 vs 7.5). The difference between the two groups was statistically significant (p = 0.0009; Mann-Whitney test). DISCUSSION: The 3P-trial has demonstrated that the preventive application of the self-occlusive lidocaine 7%-tetracaine 7% cream is very effective in reducing the procedure-associated pain during MAL-cPDT for the treatment of AK lesions.

The Efficacy of Pulsed Dye Laser Pretreated With or Without Local Anesthetic on Patients Presenting With Erythema of Face, Neck, Chest, and Extremities.

BACKGROUND AND OBJECTIVES: Erythema is one of the most common cosmetic concerns and usually responds well to pulsed dye laser (PDL) treatment. As this laser can cause significant discomfort, topical anesthesia is sometimes offered. However, it is still uncertain whether topical anesthetics can affect the outcome of the laser therapy. We performed a retrospective single site study to compare the efficacy of PDL for the treatment of erythema in patients with and without pretreatment with topical anesthetic. STUDY DESIGN/MATERIALS AND METHODS: A chart review was performed and patients who presented with erythema of face, neck, chest, and extremities pretreated with topical anesthesia (23% lidocaine/7% tetracaine ointment or 7% lidocaine/7% tetracaine ointment) undergoing PDL were reviewed and compared with another group without anesthesia. Two blinded dermatologists evaluated the postlaser procedure photographs and gave an assessment compared with baseline. RESULTS: A total of 69 patient charts were reviewed. The erythema resulted from various skin conditions including telangiectasia, cherry angioma, striae, and rosacea. The mean improvement was 2.2581 in the anesthesia group and 2.2632 in the nonanesthesia group. There was no significant difference between both groups as confirmed by a noninferiority test. CONCLUSIONS: Topical anesthesia with lidocaine and tetracaine ointment do not interfere with the efficacy of the PDL. Since pain management is essential for any cosmetic procedure, the application of a local anesthetic will enhance patient comfort and satisfaction during treatment with PDL. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Lidocaine-Epinephrine-Tetracaine Gel Is More Efficient than Eutectic Mixture of Local Anesthetics and Mepivacaine Injection for Pain Control during Skin Repair in Children: A Prospective, Propensity Score Matched Two-Center Study.

INTRODUCTION: Skin lacerations are common in children and their repair is a very unpleasant experience for a child. While pain management has been recognized as a key element of high-quality patient care, recent studies report that pain management in the pediatric emergency departments is still suboptimal. Lidocaine-epinephrine-tetracaine (LET) gel could potentially improve the traumatic experience caused by skin repair as it obviates the need for infiltration. Thus, the aim of the current study was to compare local eutectic mixture of local anesthetics (EMLA) plus mepivacaine infiltration with topical anesthetics (LET-gel). MATERIALS AND METHODS: Prospective, propensity score-matched multicenter study including all children between 3 and 16 years presented at two centers. After anesthetics (LET vs. EMLA and infiltration) standardized skin repair was performed. Pain assessment was performed using the faces pain rating scale or visual analogue scale. Follow-up, performed 2 weeks after initial presentation, assessed wound infection rates and overall satisfaction. RESULTS: Of 73 subjects 59 children (37 LET vs. 22 EMLA) were included after propensity score matching. Groups had similar baseline characteristics. Pretreatment was significantly less painful in LET versus local anesthetics group. Pain during skin repair was similar between groups (LET and EMLA with mepivacaine infiltration) and both groups demonstrated similar efficacy (procedure time, need for secondary infiltration, infection rate). Ultimately, pain levels during pretreatment and the surgical procedure were perceived significantly higher by the children than estimated by parents or surgeons. CONCLUSION: In conclusion, it appears that LET is superior to conventional anesthesia including mepivacaine infiltration in the pediatric emergency departments. Pretreatment with LET is significantly less painful but equally effective. Hence, we recommend LET as a topical anesthetic in the pediatric emergency department.

Chitosan-collagen based film for controlled delivery of a combination of short life anesthetics.

The present research was undertaken to develop a chitosan-collagen film for controlled delivery of combinations of local anesthetics. The film has been prepared by casting which is a versatile, rapid and low-cost approach distinguished by high reproducibility. The mechanical, morphological, and physicochemical properties of the films and the impact of the drug loading were evaluated. We showed that the formulations have a good combination of strength and flexibility with high water permeability. Surface morphology investigation indicates a variation in roughness depending on the loaded compound. Release studies were performed in controlled environments and the data processed by the Higuchi model to assess the dynamics of the release. The local anesthetics, lidocaine, tetracaine, and benzocaine, were uniformly distributed within the matrix and released in a rate and magnitude specific for the drug concentration and combination tunable in a range time from 6 h to 24 h. The films dissolve completely in the physiological environment within 24 h without leaving any toxic metabolites as both of the components are recognized as safe. In vitro cytotoxicity and cell proliferation tests performed on human dermal fibroblast demonstrate the biocompatibility and lack of cytotoxicity of the prepared formulations.

Efficacy and Safety of COX-2 Inhibitor Parecoxib for Rigid Cystoscopy-related Pain Management in Male Patients: A Prospective, Randomized and Controlled Study.

Using anesthetic gel may not sufficiently exclude pain perception during and after cystoscopy in male patients. To evaluate the analgesic efficacy and safety of intramuscular parecoxib (40 mg) for outpatient-based rigid cystoscopy, we performed a prospective, randomized and controlled study. Consecutive male patients requiring diagnostic cystoscopy in our hospital were divided into group A (1% tetracaine gel, n=50) and group B (parecoxib, n=51) at random. Patients received intramuscular injections of either 2 mL sterile saline in group A or 40 mg parecoxib in group B 30 min before the procedure. Tetracaine gel was injected into the urethra 3 min before the procedure in group A, with patients receiving plain lubricant gel in group B at the same time. Cystoscopy-associated pain levels were evaluated using the Visual Analog Score (VAS) during the procedure. Post-procedure urethral pain and complications were recorded and analyzed. The results showed that male patients experienced significantly less pain in group B than in group A (2.70±1.36 vs. 3.56±1.74, P=0.008). The percentage of patients with dysuria pain was not significantly different between the two groups. In addition, 24 h after cystoscopy, the patients with no previous experience of cystoscopy were more likely to declare urethral pain (59.2% vs. 33.3%, P=0.012, relative risk=1.78). No difference was observed in analgesic-related complications between the two groups. We conclude that intramuscular injection of 40 mg parecoxib may improve comfort for male patients undergoing rigid cystoscopy.

Reduction of oculocardiac reflex with Tetracaine eye drop in strabismus surgery.

INTRODUCTION: Recently, to reduce the incidence of oculocardiac reflex (OCR) in strabismus surgery, retrobulbar block and anticholinergic drugs or local anesthesia are also used. The present study evaluated the effects of Tetracaine eye drop as a topical nerve blocker on OCR during strabismus surgery. METHODS AND MATERIALS: In this randomized trial, 70 strabismus surgery candidates were randomly divided into placebo or synthetic teardrop (E) and Tetracaine eye drop (T) groups, so 3 drops of each solution were dropped in four directions of patients' eye immediately after applying anesthesia and before surgery. The incidence and severity of OCR during the stages of muscle release and incision (cutting), hemodynamic changes, the required time for OCR recovery and atropine dose were assessed. RESULTS: OCR was more seen in release phase compared to cutting phase. There were no significant differences between two group regarding the incidence and severity of OCR in the release phase (p > 0.05), but the incidence and severity of OCR in the cutting phase was more in group E than group T (p = 0.02, for both). The duration of OCR improvement (p-value = 0.74) and Atropine consumption (p-value = 0.92) did not differ between the groups. CONCLUSION: Tetracaine eye drop only reduces the incidence and severity of OCR during the incision stage of strabismus surgery.

Anesthetic Efficacy of Intranasal 3% Tetracaine plus 0.05% Oxymetazoline (Kovanaze) in Maxillary Teeth.

INTRODUCTION: Needle-free anesthetic delivery is a promising alternative to traditional anesthetic routes of administration. The purpose of this study was to determine the patient preference for and pulpal anesthetic efficacy of a 3% tetracaine plus 0.05% oxymetazoline (Kovanaze) nasal spray in maxillary lateral incisors and first premolars. METHODS: Fifty adult subjects randomly received a 3% tetracaine plus 0.05% oxymetazoline (Kovanaze) nasal spray and mock infiltration or a mock nasal spray and 2% lidocaine with 1:100,000 epinephrine infiltration at the maxillary lateral incisor or first premolar in 2 appointments spaced at least 1 week apart in a single-blind cross-over design. Pulpal anesthesia was evaluated with an electric pulp tester. Side effects and subject preferences were also recorded. RESULTS: Anesthetic success was significantly lower for the Kovanaze nasal spray and mock infiltration (22%-37%) than for the mock nasal spray and lidocaine infiltration (89%-91%). Subjects reported more unwanted effects (nasal drainage and congestion, burning, pressure, and sinus congestion) after the Kovanaze nasal spray and mock infiltration than the mock spray and maxillary infiltration. Before participating in the study, more subjects (56%) preferred the nasal spray route versus a standard infiltration (44%). After experiencing both routes of administration, 100% of subjects preferred the standard infiltration. CONCLUSIONS: The 3% tetracaine plus 0.05% oxymetazoline (Kovanaze) nasal spray provided significantly less successful pulpal anesthesia than the lidocaine infiltration, was less preferable, and caused more unwanted effects.

A Proof-of-concept Study Using Quantitative Sensory Threshold Analysis to Compare Two Intraoral Topical Anesthetics.

PURPOSE: CTY-5339A is an investigational topical anesthetic spray containing 14% benzocaine/2% tetracaine in a metered canister. Each spray delivers ∼0.2 mL of solution. This double-blind, randomized, crossover study compared the local anesthetic effect of CTY-5339A versus 14% benzocaine alone by using 2 quantitative sensory threshold experimental pain paradigms on the maxillary gingiva: pin prick test pain intensity (PPT PI) and heat pain threshold (HPT). METHODS: American Society of Anesthesiology Class 1 and 2 subjects (N = 50) were enrolled in this study. To qualify for the study, subjects were tested on the anterior maxillary gingiva with both PPT and HPT. Subjects had to report a PPT PI of ≥3 on a 0 to 10 numeric pain intensity scale on 1 of 2 consecutive pin pricks separated by 10 s, with at least one score ≥4. After PPT, mean HPT following 2 ramps in the same location had to be ≤ 46.5 °C, with each ramp beginning at 35 °C and an automatic cutoff of 50.6 °C. For treatment visits, subjects were randomly administered either 1 spray of CTY-5339A or 14% benzocaine to the anterior maxillary gingiva within 3 weeks of screening and then the alternative treatment 5 days to 2 weeks later. PPT PI and HPT were recorded immediately before drug application. After drug administration, PPT PI was recorded every minute through 5 min. Commencing at 5 min, PPT PI and HPT were recorded every 5 min through 60 min. For assessment of methemoglobin concentrations, venous blood (5 mL) was drawn from the antecubital fossa both before and 60 min after drug application. Oxygen saturation was recorded via pulse oximetry at baseline and every 10 min. FINDINGS: The AUCs for pain intensity difference from 0-30 and 0-60 min after PPT and HPT differences were significantly greater (P < 0.0001) for CTY-5339A compared with 14% benzocaine. Multiple time points on the time-action curves for PPT PI difference and HPT difference statistically (P < 0.05) favored CTY-5399A. Methemoglobin and oxygen saturation levels did not change compared with baseline after dosing with either treatment. IMPLICATIONS: Recommended doses of CTY-5339A provided significantly more profound and sustained local anesthesia than 14% benzocaine when applied to the maxillary gingiva. Significant changes in methemoglobin or oxygen saturation concentrations did not occur for either drug. ClinicalTrials.gov identifier: NCT03233737.

Effect of four local anesthetics (tetracaine, proparacaine, lidocaine, and bupivacaine) on intraocular pressure in dogs.

PURPOSE: To measure IOP in animals, it is often necessary to use topical anesthetics. The use of these drugs may cause changes in IOP and interfere with the final results. To address this issue, the effects of four local anesthetics (tetracaine, proparacaine, lidocaine, and bupivacaine) on IOP were investigated in ten adult dogs. METHODS: One drop of tetracaine was instilled in the right eye of half of the dogs and in the left eye of the other dogs; normal saline was instilled in the fellow eyes. The IOP in each dog was measured before and at 0, 5, 10, 15, 20, 25, 30, and 35 min after drug instillation using an electronic rebound tonometer. The effects of the other anesthetics were studied in the same way at intervals of at least 1 week. RESULTS: After instillation of tetracaine, the IOP decreased gradually, such that after 15 min, the IOP was significantly lower than the baseline (p = 0.022) and control values (p = 0.048). Proparacaine also reduced IOP after 10 min compared to baseline values (p = 0.046), but the two other drugs, bupivacaine and lidocaine, had no significant effect on IOP. The duration of eye anesthesia was 16, 20, 22, and 34 min for tetracaine, lidocaine, bupivacaine, and proparacaine, respectively. CONCLUSION: We recommend using drugs that combine inducing longer anesthesia with producing the smallest change in IOP, such as bupivacaine and, subsequently, lidocaine. Tetracaine and proparacaine have a significant effect on IOP, and if these drugs are used, this effect should be considered.