Short-term effects of ophthalmic topical 0.01% atropine on the ocular surface, pupil size, and subsequent subjective quality of vision in young myopic Chinese adults.

Background: Daily use of low concentrations of atropine is recommended for children undergoing myopia control therapy. While the benefits of controlling myopia progression have been confirmed, the potential unwanted side effects on the ocular surface, pupil size, and quality of vision following the administration of 0.01% atropine have not been investigated. Objective: This single-arm, self-control study aimed to investigate the short-term effects of 0.01% atropine topical eye drop (He Eye Hospital Co., Ltd., Shenyang, China) on pupil size and subjective quality of vision in participants with myopia. Each 3 mL vial of eye drops contains atropine (0.01%), sodium chloride (0.9%), and benzalkonium chloride (0.005%) in an aqueous solution. Methods: Thirty-three adults (66 eyes) were recruited for the study. The mean age of the participants recruited for this study was 24.91 ± 3.36 years. This study is registered with Clinical Trials.gov (NCT06071260). Assessments were performed at baseline and 10 h, 14 h, and 18 h following the administration of 0.01% topical atropine drop (TAD). Mesopic pupil diameter (MPD), photopic pupil diameter (PPD), higher order aberration (HOA), non-invasive tear breakup time (NITBUT), tear meniscus height (TMH), tear film lipid layer (TFLL), and Redness score (RS). Subjective assessments included the quality of vision (QoV) and the ocular surface disease index (OSDI) questionnaires. Results: Following the use of 0.01% atropine, PPD significantly increased at all the time points (p < 0.001); MPD increased significantly at 10 h and 14 h (p < 0.001 and p < 0.05, respectively). A decrease in TMH and an increase in the OSDI questionnaire scores were observed up to 10 and 14 h, respectively, after using atropine (p < 0.001). Glare (p = 0.004 at 10 h and p = 0.003 at 14 h), blurred vision (p < 0.0001 at 10 h and p = 0.035 at 14 h), and focusing difficulties (p < 0.0001 at 10 h and p < 0.0001 at 14 h) were significantly higher at both 10 h and 14 h after using atropine. No significant changes were observed in the HOA, NITBUT, and RS scores (all p > 0.05) at all time points. Conclusion: Decreased TMH, dry eye symptoms, and visual symptoms will likely persist overnight but often diminish within 18 h after using 0.01% atropine eye drops.

The Effect of Alternating Monocular Instillation of 0.125% Atropine in Korean Children with Progressive Myopia.

Objectives: To identify the effect of alternating monocular instillation (AMI) of 0.125% atropine in Korean children with progressive myopia. Methods: This retrospective single-center study included 120 children with progressive myopia. A total of 60 children (mean age 9.2 ± 2.0 years) wearing glasses who received AMI of 0.125% atropine for one year were allocated to the treatment group. The remaining 60 children (mean age 9.2 ± 1.9 years) with the same refraction, SE, and axial length (AL) who did not receive any treatments except for wearing glasses were allocated to the control group. Ocular findings and the progression rate were compared between the groups pre- and post-treatment, and adverse events were investigated in the treatment group. Results: The mean spherical equivalent (SE) at baseline was -3.87 ± 1.55 D in the control group and -3.90 ± 1.56 D in the treatment group. Pre-treatment SE, age, and AL were similar between the groups; however, post-treatment SE and AL changes were smaller in the treatment group (-0.36 ± 0.46 D/y, 0.21 ± 0.20 mm/year in the treatment group vs. -1.02 ± 0.57 D/y, 0.51 ± 0.20 mm/year in the control group) (Ps < 0.001). The pre-treatment progression rate diminished in the treatment group compared to the control group after one year (p < 0.001), and the changes in pupil size under mesopic and photopic conditions in the treatment group increased by 0.03 ± 0.05 mm and 0.76 ± 0.90 mm, respectively. Regarding adverse events, a tingling sensation was noted in two patients (3.3%) in the treatment group. Conclusions: Alternating monocular 0.125% atropine eye drop instillation may be effective and suitable for progressive myopia in Korean children.

Sublingual Atropine Administration for Clozapine-Induced Sialorrhea in Bipolar Disorder: A Case Report Highlighting its Efficacy, Safety Concerns and Challenges.

We discuss a case with off-label sublingual administration of atropine for clozapine-induced sialorrhea (CIS) after failure of two commonly used agents to manage CIS. Atropine had a demonstrable efficacy, as measured by means of sialometry conducted before and after its administration. The salivary rate, initially measured at 0.60 g/min one hour before atropine administration, reduced to 0.23 g/min two hours after administration. Sublingual administration of atropine was found to be an efficacious option for this patient, but safety issues particularly tachycardia and pragmatics such as risk of inadvertent overdose led to its discontinuation after the initial dose. Developing micro-dosing devices for sublingual atropine could enhance administration precision, reduce side effects, and provide a cost-effective solution. The case report also underscores the need to employ sialometry for the objective assessment of treatment outcomes in future research trials for hypersalivation.

Role of GABAA receptors of the dorsomedial periaqueductal grey on blood pressure and heart rate in the anesthetized rat.

The midbrain dorsomedial periaqueductal grey column (dmPAG) is involved in the regulation of cardiovascular responses. Due to the presence of Gamma-Aminobutyric acid (GABA) receptors in the dmPAG, this study aimed to investigate the role of GABAA receptors in the dmPAG on cardiovascular parameters and its possible peripheral mechanisms. The left femoral artery was cannulated, and systolic arterial pressure (SAP), mean arterial pressure (MAP) and heart rate (HR) were recorded using a Power lab system. Microinjection of saline, muscimol and bicuculline (BIC) was done using a stereotaxic device. Also, the peripheral mechanisms dependent on GABAA receptors in the dmPAG were evaluated by intravenous (i.v.) injection of hexamethonium (Hexa) and atropine (Atr) 5 min before the BIC. Results showed that BIC significantly increased ∆SAP, ∆MAP and ∆HR than the control group, but muscimol had no significant effect. Injection of Hex significantly attenuates the effect of BIC on ∆SAP and ∆MAP. Atr (i.v) significantly increased the ∆HR, and when injected before BIC microinjection, it did not affect the cardiovascular responses induced by BIC. These findings show that GABAA receptors of the dmPAG have inhibitory effects on the cardiovascular system, which are mostly mediated by the sympathetic system.

Atropine sulfate may be effective to recover the unstable hemodynamics in coronary artery spasms related to atrial fibrillation ablation procedures.

Coronary artery spasms related to atrial fibrillation ablation procedures could cause lethal ventricular fibrillation or cardiopulmonary arrest. It may be useful to try intravenous atropine sulfate while preparing urgent coronary artery angiography in hemodynamically unstable coronary artery spasms cases to prevent development of the lethal arrhythmias.

Evaluation of the clinical effects of atropine in combination with remifentanil in children undergoing surgery for acute appendicitis.

BACKGROUND: Acute appendicitis (AA) is the most common cause of acute abdomen in children. Anesthesia significantly influences the surgical treatment of AA in children, making the scientific and effective selection of anesthetics crucial. AIM: To assess the clinical effect of atropine (ATR) in combination with remifentanil (REMI) in children undergoing surgery for AA. METHODS: In total, 108 cases of pediatric AA treated between May 2020 and May 2023 were selected, 58 of which received ATR + REMI [research group (RG)] and 50 who received REMI [control group (CG)]. Comparative analyses were conducted on the time to loss of eyelash reflex, pain resolution time, recovery time from anesthesia, incidence of adverse events (AEs; respiratory depression, hypoxemia, bradycardia, nausea and vomiting, and hypotension), intraoperative responses (head shaking, limb activity, orientation recovery, safe departure time from the operating room), hemodynamic parameters [oxygen saturation (SPO2), mean arterial pressure, heart rate, and respiratory rate], postoperative sedation score (Ramsay score), and pain level [the Face, Legs, Activity, Cry, Consolability (FLACC) Behavioral Scale]. RESULTS: Compared with the CG, the RG showed significantly shorter time to loss of eyelash reflex, pain resolution, recovery from anesthesia, and safe departure from the operating room. Furthermore, the incidence rates of overall AEs (head shaking, limb activity, etc.) were lower, and influences on intraoperative hemodynamic parameters and stress response indexes were fewer. The Ramsay score at 30 min after extubation and the FLACC score at 60 min after extubation were significantly lower in the RG than in the CG. CONCLUSION: ATR + REMI is superior to REMI alone in children undergoing AA surgery, with a lower incidence of AEs, fewer influences on hemodynamics and stress responses, and better post-anesthesia recovery.

Atropine: Updates on myopia pharmacotherapy.

The prevalence of myopia has rapidly increased over the last 30 years, with the World Health Organization estimating a worldwide incidence of 23%, projected to increase to 50% by 2050. The myopia epidemic has prompted a reincarnation in efforts to overcome this challenge. The exploration of atropine use in myopia was a result due to a lack of treatment in effect. This study aimed at reviewing the role of atropine in the management of myopia worldwide based on currently available findings. A literature search was conducted using PubMed/MEDLINE and Google Scholar for studies published up to April 2022 inclusive. Articles with high or medium clinical relevance were selected for this review. Multiple studies have demonstrated the relevance and efficacy rates of different concentrations of atropine, despite still insufficiently explained the exact site and mechanism of action of atropine in slowing myopia progression. Currently available findings highlight that topical atropine opened a new page in pharmacotherapy of myopia and have shown a high therapeutic effect on myopia progression in Asian and European child population, irrespective of ethnicity. There is potential for myopia control with fewer side effects using lower concentrations but still exists a room for improvement, underscoring the requirement of modified atropine topical preparations with increased bioavailability, potentially with nanoparticle formulations, to enable the effective management of myopia.

Impact of atropine use for myopia control on intraocular pressure in children: A comprehensive review including postpupil dilation intraocular pressure changes.

Topical atropine has been widely used for controlling myopia progression in children, yet its long-term efficacy and safety, including potential intraocular pressure (IOP) elevation, are still being studied. The mydriasis and cyclopegia induced by atropine may reduce traction on the trabecular meshwork, together with pigment released into anterior chamber due to the friction between the iris and lens during pupil dilation, may obstruct and reduce the trabecular outflow. This review first explores postdilation IOP changes across different groups - healthy individuals, glaucoma patients, and children. The response to pupil dilation varies widely, with IOP potentially increasing or decreasing. Glaucoma patients, whether with open or closed-angle glaucoma, may experience more significant IOP rises postdilation. The second section examines IOP effects in children using topical atropine for myopia, where most of the 25 reviewed studies showed nonsignificant IOP changes, although slight increases were observed in a few. In addition, no alterations in the retinal nerve fiber layer thickness were found. However, the research on children's IOP under topical atropine is constrained by small sample sizes, cross-sectional studies, brief follow-ups, and often lacks control groups or pretreatment IOP measurements. Given the extended atropine use for myopia and the significant individual variation in IOP response, we recommend routine IOP monitoring for children receiving topical atropine.

Impact of coronavirus disease 2019 restrictions on the efficacy of atropine 0.01% eyedrops for myopia control - Findings from the Western Australia Atropine for the Treatment of Myopia study.

This study explored the impact of short-term coronavirus disease 2019 (COVID-19) restrictions on the efficacy of atropine 0.01% eyedrops on myopia control in a multiethnic cohort of Australian children. In the Western Australia Atropine for the Treatment of Myopia study, 104 and 49 children were randomized to receive atropine 0.01% eyedrops and a placebo, respectively. We compared the 1-year myopia progression and axial elongation following the 2-month lockdown in 2020 to the same months in 2019 and 2021, i.e., the 1-year myopia progression up to May 2019-October 2019 (non-COVID-19) versus the 1-year progression up to May 2020-October 2020 (COVID-19 period), and the 1-year progression up to May 2021-October 2021 (non-COVID-19) versus the 1-year progression up to the same months in 2020. After excluding participants who withdrew, completed their treatment phase prior May 2020, or those whose study visits did not fall between May 2020 and October 2020, 65 participants (mean age at baseline = 11.8 ± 2.5 years) were included in the final analysis (49 in the treatment group; 16 in the placebo group). After correcting for age, sex, and ethnicity, there was no significant main effect of the short-term lockdown on the rate of spherical equivalent or axial length change. However, there was a lockdown × treatment interaction effect on the rate of axial elongation (P = 0.007). This was such that in the treatment group, the 1-year axial elongation was faster during lockdown by 0.056 mm compared to the nonlockdown periods (P = 0.009), while the rate of axial elongation in those on the placebo eye drops was similar during lockdown and nonlockdown. Our findings suggest that there is a decreased efficacy of low-concentration atropine even with relatively lenient restrictions lasting for a few months.

Add-on effect of using 0.05% atropine in fast progressors of orthokeratology: A preliminary retrospective study.

PURPOSE: To investigate the potential benefit of combining orthokeratology (OK) lenses with 0.05% atropine ophthalmic solution on the efficacy of myopia control in the fast progressors of OK. METHODS: Average axial length (AL) elongation of both eyes in 70 participants using OK lenses alone or OK lenses combined with 0.05 % atropine ophthalmic solution was retrospectively reviewed. During the observation period (phase 1), all participants exhibited an AL elongation that exceeded 0.15 mm over a 6-month period or 0.3 mm over a 12-month period. Subsequently, the participants were divided into two groups: one group received nightly 0.05 % atropine ophthalmic solution in addition to OK lenses for another 1 year (OKA), while the other group continued using OK lenses alone (phase 2). The changes in AL elongation over time and the differences in AL elongation between the two groups were then compared. RESULTS: The baseline and phase 1 demographics and characteristics of the participants was similar between the two groups (all p > 0.05). when considering a one-year timeframe, the OKA group displayed a significantly less AL elongation compared to the OK group (0.14 ± 0.13 mm vs 0.27 ± 0.12 mm, p < 0.001). Within the OKA group, the AL elongation in the second half of the year was significantly faster than in the first half (0.12 ± 0.11 mm vs 0.02 ± 0.14 mm, p = 0.01). Conversely, there was no significant difference in AL elongation between the OK group in the first and second half of the year (0.12 ± 0.07 mm vs 0.15 ± 0.08 mm, p = 0.71). The combination of 0.05 % atropine ophthalmic solution had a significant effect on 1-year AL elongation (p < 0.001). CONCLUSIONS: This study provided preliminary evidence that the combination of OK lenses and 0.05% atropine ophthalmic solution can significantly enhance the effectiveness of myopia control.

Myopia Control in Caucasian Children with 0.01% Atropine Eye Drops: 1-Year Follow-Up Study.

Background and Objectives: Myopia is the most widespread ocular disorder globally and its prevalence has been increasing over the past decades. Atropine eye drops stand out as the only pharmacological intervention used in clinical practice to control myopia progression. The aim of this study was to explore the effect of 0.01% atropine eye drops on myopia progression. Patients and Methods: Healthy children aged 6-12 years with cycloplegic spherical equivalent (SE) from -0.5 D to -5.0 D and astigmatism ≤1.5 D were included. Myopia progression was assessed by changes in SE and axial length (AL) over 1 year and SE changes 1 year before the study enrollment and during the 1-year follow-up. Adverse events were evaluated based on complaints reported by either parents or the children themselves during follow-up visits. Results: The analysis involved 55 patients in the 0.01% atropine eye drops group and 66 in the control group. After the 1-year follow-up, the change in SE was -0.50 (-2.25-0.50) D in the control group compared to -0.50 (-1.50-0.50) D in the 0.01% atropine group (p = 0.935); AL change was 0.31 (0.18) mm in the control group and 0.29 (0.18) mm in the 0.01% atropine group (p = 0.480). The change in SE was -0.68 (-2.0--0.25) D/year before the study and remained similar -0.50 (-2.25-0.25) D over the 1-year follow-up in the control group (p = 0.111); SE change was reduced from -1.01 (-2.0--0.25) D/year before the study to -0.50 (-1.5-0.5) D over the 1-year follow-up in the 0.01% atropine group (p < 0.001). In the 0.01% atropine group, ten (16.4%) children experienced mild adverse events, including blurred near vision, ocular discomfort, photophobia, dry eyes, and anisocoria. Conclusions: Compared to the control group, the administration of 0.01% atropine eye drops demonstrated no significant effect on changes in SE and AL over a 1-year follow-up. However, children in the 0.01% atropine group initially experienced higher myopia progression, which decreased with treatment over the course of 1 year. Future studies should explore the long-term effects, rebound effects, potential genetic associations, and efficacy of higher doses of atropine in managing myopia progression.

L-carnitine: A novel approach in management of acute cholinesterase inhibitor insecticide poisoning.

Cholinesterase inhibitors (ChEIs) insecticide poisoning is a serious global health concern that results in hundreds of thousands of fatalities each year. Although inhibition of the cholinesterase enzyme is the main mechanism of ChEI poisoning, oxidative stress is considered the mechanism underlying the related complications. The study aimed to assess the oxidative status of the patients with ChEI insecticide poisoning and the role of L-carnitine as adjuvant therapy in their management. Human studies on the efficacy and safety of L-carnitine in treating insecticide poisoning are limited despite its growing research interest as a safe antioxidant. This prospective study was conducted on eighty patients with acute ChEIs insecticide poisoning admitted to Alexandria Poison Center, Alexandria Main University Hospital, Egypt. Patients were allocated into two equal groups randomly. The L-carnitine (LC) group received the conventional treatment (atropine & toxogonin) and LC and the standard treatment (ST) group received the standard treatment only. Outcome measures were fatality rate, the total administered dose of atropine & toxogonin, length of hospital stay, and the requirement for ICU admission or mechanical ventilation. The study results revealed that malondialdehyde (MDA) significantly decreased in the LC group. Cholinesterase enzyme levels increased significantly after treatment in the LC group than in the ST group. The LC group needed lower dosages of atropine and toxogonin than the ST group. Also, the LC group showed no need for ICU admission or mechanical ventilation. The study concluded that LC can be considered a promising adjuvant antioxidant treatment in acute ChEIs pesticide poisoning.

Severe Amitraz Poisoning: A Case of Successful Emergency Intervention.

Amitraz poisoning is being increasingly seen in clinical practice, presenting physicians with challenges due to its rapidity of onset of severe clinical features, its similarity with organophosphate poisoning and the absence of specific antidotes. Early initiation and appropriate treatment are vital for favourable outcomes. Our case report is of a 40-year-old male who presented to us with grave clinical features following deliberate ingestion of Amitraz in a suicidal attempt. On arrival, he had bradycardia, hypotension, respiratory depression, and altered sensorium. Immediate administration of atropine stabilised his vital signs. Laboratory investigations revealed uncommon electrolyte imbalances, which were promptly corrected. The patient received supportive care in the intensive care unit (ICU), regained consciousness within three days, and was discharged after a week of hospitalisation. Despite the rapid onset and severity of symptoms caused by Amitraz poisoning, early intervention and supportive care can lead to a full recovery. This case underscores the importance of promptly recognising Amitraz poisoning and initiating treatment, its similarity with organophosphate poisoning and the role of atropine. Further research is needed to establish comprehensive management guidelines for tackling this emerging poisoning hazard.

Atropine as an Adjunct in the Management of Pediatric Patients With Hypertrophic Pyloric Stenosis: A Single Institution Experience and Review of the Literature.

Infantile hypertrophic pyloric stenosis (IHPS) is a condition whereby there is a thickening of the pyloric muscle, leading to obstruction of the gastric outflow. Typically present within three to five weeks of life, it presents as postprandial non-bilious projectile vomiting. Commonly, a pyloromyotomy is the gold standard to relieve the obstruction. However, in a subset of patients not amenable to undergo surgery or anesthesia, or for postoperative persistent or recurrent obstruction, atropine may offer an alternative treatment. A retrospective review was performed on pediatric patients with hypertrophic pyloric stenosis utilizing the electronic medical record. Data included were demographics, workup data, treatment, outcomes, and symptom resolution. Approval was obtained by the institutional review board of the host institution. Five pediatric patients, with an average age of 2.1 months, received atropine treatment for IHPS. The average time to reach full feeds since the initiation of atropine was approximately four days. Three of the five patients were successfully managed with IV atropine, which was then transitioned to oral atropine and tapered off as outpatients, leading to the resolution of symptoms. The remaining two patients were considered failures of medical management and subsequently required surgery. Atropine use as an alternative treatment for IHPS may be considered when patients are not able to undergo surgery or anesthesia or have recurrent or persistent obstructive symptoms postoperatively. In this limited study, atropine was found to be safe and effective. Randomized controlled studies may lend additional merit to this therapy in the future.

Frequency-dependent effects of 0.05% atropine eyedrops on myopia progression and peripheral defocus: a prospective study.

BACKGROUND: Atropine, specifically 0.05% eyedrops, has proven effective in slowing myopia progression. This study aims to investigate peripheral refraction (PR) characteristics in myopic children treated with 0.05% atropine eyedrops at different frequencies. METHODS: One hundred thirty-eight myopic children completed this one-year prospective study, randomly assigned to once daily (7/7), twice per week (2/7), or once per week (1/7) groups. Spherical equivalent (SE) and axial length (AL) were measured. PR was assessed using a custom-made Hartmann-Shack wavefront peripheral sensor, covering a visual field of horizontal 60° and vertical 36°. Relative peripheral refraction (RPR) was calculated by subtracting central from peripheral measurements. RESULTS: After one year, SE increased more significantly in the 1/7 group compared to the 7/7 group (P < 0.001) and 2/7 group (P = 0.004); AL elongation was also greater in the 1/7 group compared to the 7/7 group (P < 0.001). In comparison with higher frequency groups, 1/7 group exhibited more myopic PR in the fovea and its vertical superior, inferior, and nasal retina; and less myopic RPR in the periphery retina after one-year (P < 0.05). Additionally, RPR in the 7/7 group demonstrated myopic shift across the entire retina, the 2/7 group in temporal and inferior retina, while the 1/7 group showed a hyperopic shift in the superior retina (P < 0.05). Moreover, myopic shift of RPR in the temporal retina is related to less myopia progression, notably in the 7/7 group (P < 0.05). CONCLUSIONS: Atropine inhibits myopia progression in a frequency-dependent manner. The once-daily group showed the slowest myopia progression but exhibited more myopic shifts in RPR. Additionally, RPR in the temporal retina was related to myopia progression in all groups. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2100043506. Registered 21 February 2021, https://www.chictr.org.cn/showproj.html?proj=122214.

Absorption and attachment of atropine to etafilcon A contact lenses.

PURPOSE: Myopia (short-sightedness) is a growing vision problem worldwide. Currently atropine eye drops are used to control the progression of myopia but these suffer from potential lack of bioavailability and low ocular residence time. Commercially available myopia control contact lenses are also used to limit myopia progression, but neither atropine nor contact lenses individually completely stop progression. Development of myopia control contact lenses which could deliver therapeutic doses of atropine is thus desirable and may provide increased efficacy. This study was designed to explore the feasibility of attaching atropine to etafilcon A contact lenses through an esterification reaction. METHODS: Carboxylic acid groups on etafilcon A contact lenses were quantified using Toluidine Blue O. The carboxylic acid groups in etafilcon A contact lenses were activated using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC-HCl) and N-hydroxysuccinimide (NHS) crosslinkers after which atropine was added to undergo potential binding via esterification. Atropine was released from lenses by alkaline hydrolysis. Reverse phase high performance liquid chromatography (HPLC) was used to detect and quantify the released atropine and its degradation products in solution. Contact lenses that had not been activated by EDC-NHS (controls) were also examined to determine the amount of atropine that could be absorbed rather than chemically bound to lenses. RESULTS: Each etafilcon A contact lens contained 741.1 ± 5.5 µg carboxylic acid groups which may be available for esterification. HPLC had a limit of detection for atropine of 0.38 µg/mL and for tropic acid, an atropine degradation product, of 0.80 µg/mL. The limits of quantification were 1.16 µg/mL for atropine and 2.41 µg/mL for tropic acid in NH4HCO3. The etafilcon A lenses adsorbed up to 7.69 µg atropine when incubated in a 5 mg/mL atropine solution for 24 h. However, there was no evidence that atropine could be chemically linked to the lenses, as washing in a high concentration of NaCl removed all the atropine from the contact lenses with no atropine being subsequently released from the lenses after incubating in 0.01 N NH4HCO3. CONCLUSIONS: Etafilcon A contact lenses contain free carboxylic acids which may be an appropriate option for attaching drugs such as atropine. Etafilcon A lenses adsorbed up to 7.69 µg atropine, which would be more than enough to deliver atropine to eyes to control myopia. However, atropine could not be chemically bound to the carboxylic acids of the etafilcon A lenses using this methodology.

Stability of Multicomponent Antidote Parenteral Formulations for Autoinjectors against Chemical War Agents (Neurotoxics).

Combinations of different drugs are formulated in autoinjectors for parenteral administration against neurotoxic war agents. In this work, the effects on the chemical stability of the following three variables were studied: (i) type of drug combination (pralidoxime, atropine, and midazolam versus obidoxime, atropine, and midazolam); (ii) pH (3 versus 4); and (iii) type of elastomeric sealing material (PH 701/50 C BLACK versus 4023/50 GRAY). Syringes were stored at three different temperatures: 4, 25, and 40 °C. Samples were assayed at different time points to study the physical appearance, drug sorption on the sealing elastomeric materials, and drug content in solution. Midazolam was unstable in all tested experimental conditions. Drug adsorption was observed in both types of sealing elastomeric materials and was significantly (p < 0.01) dependent on the lipophilicity of the drug. The most stable formulation was the combination of pralidoxime and atropine at pH 4 with the elastomeric sealing material 4023/50 GRAY.