Serum Lidocaine Research Articles

Effect of epinephrine on the absorption of lidocaine following application to the oral mucosa in rats

BackgroundWe investigated the role of epinephrine in prolonging the localization of lidocaine on the oral mucosa and inhibiting its absorption in the blood of rats.MethodsWe used 7–8-week-old pathogen-free Wistar male rats (n = 128) for our study. We divided them into the control group administered with 14C-labeled lidocaine hydrochloride gel only and the study group administered with 14C-labeled lidocaine hydrochloride gel with epinephrine. The medications were administered in the palatal mucosa of the rats. The amount of mucosa, palatine bone, and serum lidocaine was measured by radioactivity using a liquid scintillation counter and was observed using autoradiograms.ResultsInitially, there was no significant difference in the lidocaine levels between the lidocaine and lidocaine with epinephrine groups in the palatal mucosa (751.9 ± 133.8 vs. 669.8 ± 101.6 ng/mg [2 min]). After 4 min, the values were significantly lower in the lidocaine with epinephrine group (1040.0 ± 142.8 vs. 701.2 ± 109.0 ng/mg [20 min]). After 40 min, the lidocaine level became significantly higher in the lidocaine with epinephrine group (586.8 ± 112.4 vs. 1131.3 ± 155.2 ng/mg [40 min]). Similar results were observed in the palatine bone and serum.ConclusionEpinephrine prolonged the localization of lidocaine applied to the mucosa and inhibited its absorption into the bloodstream of rats. Clinical studies are required to evaluate the use of epinephrine-containing topical anesthetics on the oral mucosa.

Rectus sheath single-injection blocks: a study to quantify local anaesthetic absorption using serial ultrasound measurements and lidocaine serum concentrations.

Rectus sheath blocks are an established option for analgesia following abdominal surgery, but pharmacokinetic data are limited. This study sought to characterise the absorption of lidocaine injectate and the pharmacokinetics of lidocaine after rectus sheath injection. Bilateral rectus sheath single-injection blocks were given to 10 patients undergoing general or urological surgery. Afterwards, serial lidocaine serum levels and ultrasound measurements of the rectus sheath injectate reservoir were collected. Injectate within the rectus sheath was visible with ultrasound up to 12h after injection. However, the rate of drug absorption exceeded that of injectate disappearance. Peak serum concentration occurred within 30min with average peak concentrations of 1.65μg/ml. Lidocaine clearance was lower than reported in young healthy subjects. The body mass index positively correlated with lidocaine terminal phase half-life, and clearance negatively correlated with age. The study provides the first data describing lidocaine pharmacokinetics after rectus sheath injection. Peak serum concentrations transiently achieved systemic levels associated with pain relief after a single bolus injection. The data from this study could be used to develop a regime using single shot rectus sheath blockade with a bolus of lidocaine followed by infusion using bilateral rectus sheath catheters.

Serum Concentrations of Lidocaine During Bariatric Surgery

Lidocaine has been shown to be clinically beneficial during bariatric surgery. However, information about lidocaine serum concentrations in this setting is scarce. This prospective clinical trial included 42 obese patients undergoing laparoscopic bariatric surgery. They received lidocaine based on adjusted body weight. Administration began with a 1.5 mg·kg bolus of intravenous lidocaine followed by a continuous infusion of 2 mg·kg·hour. After skin closure, administration was decreased to 1 mg·kg·hour until discharge from the recovery room. No serum concentrations of lidocaine were outside the usual accepted range (1.5-5 µg·mL).

Muscle injections with lidocaine improve resting fatigue and pain in patients with chronic fatigue syndrome.

ObjectivePatients with chronic fatigue syndrome (CFS) complain of long-lasting fatigue and pain which are not relieved by rest and worsened by physical exertion. Previous research has implicated metaboreceptors of muscles to play an important role for chronic fatigue and pain. Therefore, we hypothesized that blocking impulse input from deep tissues with intramuscular lidocaine injections would improve not only the pain but also fatigue of CFS patients.MethodsIn a double-blind, placebo-controlled study, 58 CFS patients received 20 mL of 1% lidocaine (200 mg) or normal saline once into both trapezius and gluteal muscles. Study outcomes included clinical fatigue and pain, depression, and anxiety. In addition, mechanical and heat hyperalgesia were assessed and serum levels of lidocaine were obtained after the injections.ResultsFatigue ratings of CFS patients decreased significantly more after lidocaine compared to saline injections (p = 0.03). In contrast, muscle injections reduced pain, depression, and anxiety (p < 0.001), but these changes were not statistically different between lidocaine and saline (p > 0.05). Lidocaine injections increased mechanical pain thresholds of CFS patients (p = 0.04) but did not affect their heat hyperalgesia. Importantly, mood changes or lidocaine serum levels did not significantly predict fatigue reductions.ConclusionThese results demonstrate that lidocaine injections reduce clinical fatigue of CFS patients significantly more than placebo, suggesting an important role of peripheral tissues for chronic fatigue. Future investigations will be necessary to evaluate the clinical benefits of such interventions.

Glasgow Coma Scale Improvement after Lidocaine Infusion in Moderate Traumatic Brain Injury

Since the Glasgow Coma Scale was developed 40 years ago it has been accepted throughout the world as a method for assessing impaired consciousness. Fourty moderate TBI patients were simple randomly divided into 2 groups: group A take normal saline infusion without lidocaine as control group (N=20), and group B take normal saline with lidocaine at rate 1 mg/kg/BW infusion as treated groups (N=20). Serum samples were collected at before induction and 2 hours after giving infusion treatment to measure serum IL-6 and PLA2 level, and lidocaine serum concentration. GCS were measured before induction and after 24 hours surgery. Data were analyzed using analytic statistic with paired t test to measure serum IL-6, PLA2, & lidocaine serum level before induction and after 2 hours. The correlation of serum IL-6, PLA2 and GCS was measure with Separman correlation. A P value less than 0.05 were considered significant. The result are both serum IL-6 and PLA2 levels were significantly lower in saline with lidocain infusion group (p<0.005) with Mann Whitney and Dependent t test statistically analyses. The lower serum IL-6 and PLA2 levels, the higher GCS value. GCS measurement was significantly higher in lidocaine infusion group (p<0.05) with dependent t test. The decrese in serum IL-6 and PLA2 was correlated with the dosage of lidocaine. Medium doses of lidocaine achieved the optimum decreases in the serum IL 6 and PLA2 level. Therefore, inhibition of the composition and secretion of IL-6 and PLA2 levels by Lidocaine might be one of the mechanisms involved in decreasing inflammatory reaction and cellular damage in brain cells, and may be responsible for the neuroprotective effect after TBI. Glasgow Coma Scale was improving after infusion with lidocaine 1 mg/ kg/ hr during traumatic brain injury surgery by decreasing IL-6 and PLA2 plasm.

Elevated lidocaine serum levels following the use of a needle free device in healthy adult volunteers.

There is increased concern regarding circulating levels of lidocaine immediately after the use of a needle-free device with buffered lidocaine. As a result, we conducted a prospective study to assess lidocaine circulation after the use of a needle-free device for the delivery of a local anesthetic in 10 healthy adult subjects. After informed consent, 2 peripheral intravenous catheters were placed in the antecubital fossa of each arm. Two milligrams of 1% buffered lidocaine was administered by the study physician via the needle-free device on the dorsum of the subject's hand. Within 2 minutes, a third intravenous catheter was placed in the location of the lidocaine administration and 5 mL of blood was collected from all 3 sites. If blood samples returned positive for lidocaine, they were also collected 1 hour and 2 hours after administration. Toxic levels of lidocaine were found in blood drawn from 2 subjects immediately after lidocaine administration. Results also showed that certain subjects had increasing levels of lidocaine over time. Other subjects also had increasing lidocaine serum levels from blood drawn on the arm opposite the administration site. We concluded that there may be systemic lidocaine levels with the administration of the needle-free device and that these levels may reach the toxic range in adults. Further investigation will be required to determine whether this finding has clinical significance, especially considering the smaller body mass of children.

Lidocaine serum concentration after epidural administration in combination with morphine and fentanyl in rabbit – A preliminary study

Morphine and fentanyl are often used as adjuvants in epidural anesthesia to prolong analgesia. The aim of this study was to evaluate the impact of addition of morphine or fentanyl to lidocaine on serum lidocaine concentrations in rabbits after epidural administration. During general anesthesia, rabbits of the group L received epidurally 2% lidocaine, rabbits of the group LM 2% lidocaine and morphine, and rabbits of the group LF 2% lidocaine and fentanyl. Blood for determination of serum lidocaine concentration was taken before anesthesia and in first 90min after epidural administration. After 5, 10, and 25min in the group L the lidocaine serum concentrations were the lowest, while in the group LM the lidocaine serum concentrations were the highest. Morphine and fentanyl did not cause significant changes of serum lidocaine concentration in rabbits and may be used as adjuvant in epidural anesthesia without significant increase in lidocaine absorption from epidural space.

Safety of peak serum lidocaine concentration after Mohs micrographic surgery: A prospective cohort study

Large volumes of dilute local anesthesia are increasingly used not only for liposuction but also for other large cutaneous surgeries, including skin cancer excision. Although the lidocaine serum levels and peaks after injection of tumescent anesthesia in the trunk were shown to be safe even when used in high doses, the levels after use of less dilute (1% lidocaine) solutions for facial cancer surgery have not been described. We sought to ascertain whether perioperative peak lidocaine levels during Mohs micrographic surgery approach thresholds for lidocaine toxicity. In this prospective cohort study, each Mohs micrographic procedure was commenced per routine protocol, with use of injectable 1% lidocaine with 1:200,000 epinephrine and 1:10 8.4% bicarbonate for local anesthesia. Six peripheral blood draws of 5 mL each were performed and sent for serum lidocaine concentration measurement. Blood draws were obtained before and after the first two stages of Mohs micrographic surgery, and before and after the third stage or wound repair, as appropriate. Subjects and investigators reported any symptoms or signs of lidocaine toxicity. The main outcome measures include: (1) number of subjects exhibiting at least one level higher than the threshold for toxicity; and (2) sustained elevated lidocaine levels in one or more subjects. Mean total lidocaine volume per subject was 15 mL (range: 5-48 mL). The highest peak serum lidocaine level detected at any time point (blood draw) for any subject was 0.3 microg/mL. Mean serum lidocaine level for all 6 time points was less than 0.1 microg/mL and was thus not detected. Detectable lidocaine levels were found to be associated with higher mean (P = .028) and median (P = .008) total lidocaine doses. Because no toxic levels were detected, it was not possible to measure sustained high lidocaine levels. Limitations of this study include the lack of use of very concentrated (eg, 2% vs 1%) lidocaine solution. Lidocaine use during Mohs micrographic surgery does not appear to result in serum lidocaine levels approaching toxic levels even when relatively high total lidocaine doses are used. There is an association between higher total lidocaine dose and perioperative peak serum lidocaine level.

Efficacy of tumescent local anesthesia with variable lidocaine concentration in 3430 consecutive cases of liposuction

Lidocaine toxicity is a potential complication related to using tumescent local anesthesia (TLA) as the exclusive form of pain management in surgical procedures. We sought to determine the minimum concentration of lidocaine in the tumescent solution required to provide adequate anesthesia in patients undergoing liposuction using TLA exclusively. Liposuction using TLA exclusively was performed in 3430 procedures by the same surgeon. The initial concentration of 1000 mg/L lidocaine in the tumescent solution was gradually reduced to find the minimum required for adequate anesthesia. Adequate anesthesia was achieved using a lidocaine concentration of 500 mg/L saline in all areas treated and 400 mg/L saline for most of the areas treated. Data are based on the specific TLA technique used by the same surgeon. Lidocaine serum levels were not analyzed. For patients undergoing liposuction using TLA exclusively, the concentration of lidocaine in the normal saline solution required for adequate anesthesia is 400 mg/L for most body areas and 500 mg/L for some sensitive areas.

Pharmacokinetics of Anorectal Nifedipine and Lidocaine (Lignocaine) Ointment following Haemorrhoidectomy

This study aimed to assess whether topical anorectal application of an ointment containing nifedipine (0.3% w/w) and lidocaine (lignocaine) [1.5% w/w] to patients undergoing Milligan-Morgan haemorrhoidectomy achieves pharmacologically relevant serum concentrations of the active ingredients and has any haemodynamic effects or adverse effects. A single dose of 3 g of study ointment was circumferentially applied inside the anus to 24 patients (17 males and 7 females) aged 23-71 years (mean +/- SD: 42.9 +/- 4.9 years) during postoperative dressing after Milligan-Morgan haemorrhoidectomy from March 2007 to January 2008. Blood samples for the determination of nifedipine and lidocaine serum concentrations were drawn before surgery and at 20, 40, 60, 90, 120, 240, 360, 480 and 720 minutes after application. Serum concentrations of nifedipine and lidocaine were determined by a high-performance liquid chromatography method in order to calculate pharmacokinetic parameters. Patients' BP, heart rate and ECG readings were monitored during the study. Chromatographic signals of nifedipine were sporadically observed in only five patients (20.8%), consistent with therapeutically negligible concentrations and insufficient to permit calculation of any pharmacokinetic parameters. The serum concentrations of nifedipine in these five patients ranged from 5.9 to 18.8 ng/mL. Lidocaine concentrations were detectable in all patients. The means +/- SD and medians of pharmacokinetic parameters for lidocaine were as follows: maximum serum concentration (C(max)) 245.1 +/- 370.8 ng/mL, 73.6 ng/mL; time to reach C(max) (t(max)) 69.2 +/- 78.3 minutes, 40 minutes; area under the serum concentration-time curve from 0 to 6 hours (AUC(6)) 756.5 +/- 1254.1 ng.h/mL, 238.2 ng.h/mL. Only three patients had maximum serum concentrations above 1000 ng/mL (1037.8, 1044.75 and 1364.1 ng/mL). These outlier concentrations were four to five times lower than the threshold of CNS lidocaine toxicity (5000-6000 ng/mL). No serious local or systemic adverse events were observed throughout the study, and no subjects developed arrhythmias or significant ECG changes. Neither BP nor mean heart rate varied significantly after application of a single dose. This study demonstrates that single-dose topical application of an ointment containing nifedipine (0.3% w/w) and lidocaine (1.5% w/w) to patients undergoing Milligan-Morgan haemorrhoidectomy is safe to use. Following application onto damaged anorectal mucosa, nifedipine and lidocaine are absorbed into the bloodstream in small quantities that do not have any major implications for the safety of the product. Further studies are required to evaluate nifedipine and lidocaine concentrations in serum using a multiple-dose regimen.

Lack of systemic absorption of lidocaine from 5% patches placed on horses

ObjectiveTo measure concentrations of lidocaine serum after application of two 5% patches on horses. Study designProspective experimental trialAnimals Six client-owned, systemically healthy horses. MethodsThe hair was clipped on the medial aspect above the carpus of both fore limbs and 2 patches of 5% lidocaine were applied within 30 minutes of jugular catheter placement and the area was then bandaged. Venous blood was drawn from a jugular vein catheter that was inserted using lidocaine as a local block. Samples were drawn immediately before and at 2, 4, 6, 8, and 12 hours after patch application. The presence of lidocaine in serum was determined using an ELISA test. ResultsLidocaine was detected in the serum of three horses at 0 hours immediately following the local block for catheter placement. Lidocaine was not detected at any other time from 2 to 12 hours. There was mild erythema at the site of patch placement at 12 hours in one horse but this resolved within 1 hour of patch removal. There were no other apparent adverse effects from the patches on any other horse. ConclusionFive percent lidocaine patches applied proximally to the carpus did not result in detectable systemic concentrations of lidocaine.Clinical relevance Any analgesic effects that might be produced by application of 5% lidocaine patches on horses will not be due to systemic absorption of the drug.

Effectiveness of Intrauterine Anesthesia for Pain Relief During Fractional Curettage

To study the effectiveness of intrauterine anesthesia for pain relief during fractional curettage. A double-blinded, randomized, placebo-controlled trial was conducted in 66 patients with abnormal uterine bleeding undergoing fractional curettage under paracervical block, using 10-mL 1% lidocaine plus intrauterine 5-mL 2% lidocaine (n = 33) or saline (n = 33). The primary outcome was the maximum pain score measured with a 10-cm visual analog scale. Other outcomes measured included pain profile, number of patients with pain score more than 4, each patient's global satisfaction index, adverse events, and serum lidocaine profile. The 2 groups were comparable in age, body mass index, education, socioeconomic status, menopausal status, and parity. Compared with the saline group, the lidocaine group had a significantly lower median value for the maximum pain score (2.3 versus 4.7, P = .022) and fewer patients with a pain score more than 4 (33.3% versus 60.6%, P = .026). The pain scores were lower at the endocervical curettage and the uterine curettage steps. There was no difference between the 2 groups in other outcomes. The number needed to treat to prevent a case with a pain score more than 4 was 3.7 (95% confidence interval 2.4-38.5). The addition of intrauterine anesthesia to paracervical block can further reduce pain during fractional curettage without increasing adverse effects. I.

A pilot study on lidocaine tape therapy for convulsions with mild gastroenteritis

The aim of this study was to clarify the efficacy and safety of lidocaine tape therapy (LDT) in patients with convulsions with mild gastroenteritis (CwG). Twenty-one consecutive episodes of CwG were treated with LDT therapy. The dose of LDT was 36 mg in patients with body weights of <15 kg, 54 mg in those with body weights between 15 and 20 kg, and 72 mg in those with body weights of >20 kg. LDT was attached on the back of each patient every 12 h. Application of LDT was continued for 48 h. The serum levels of lidocaine (LD) were measured 4 h after the first attachment of LDT. The seizures completely ceased in 13 episodes (62%) after the application of LDT, while a recurrence of seizures was observed in the other 8 episodes. Drip infusion of LD was performed in 4 of these 8 episodes. The serum LD levels were only measurable in 6 infants (average, 0.4 μg/ml; range, 0.2–0.5 μg/ml). In the other patients, the serum LD levels were below the lower limit of measurement. Adverse effects of LDT were not observed in any patients. LDT therapy was safe and effective in patients with CwG.

Serum Lidocaine and Mepivacaine Level during Axillary Brachial Plexus Block

Serum Lidocaine and Mepivacaine Level during Axillary Brachial Plexus Block

Assessment of monoethylglycinexylidide as measure of liver function for patients with chronic viral hepatitis

The liver metabolizes lidocaine by oxidative deethylation to form monoethylglycinexylidide (MEGX), an analyte proposed as an index of liver function. We determined MEGX and lidocaine serum concentrations with the TDx (Abbott Laboratories) at baseline and 15, 30, 60, and 90 min after the intravenous administration of lidocaine (1 mg/kg), analyzing specimens from 12 apparently healthy volunteers and 40 patients with chronic viral hepatitis diagnosed by liver biopsy and serum tests. The patients were grouped on the basis of the histology activity index. The following laboratory tests were performed on serum specimens from all subjects: albumin (ALB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, total bilirubin, and prothrombin time. The results showed no significant difference among the four groups for the concentrations of MEGX, lidocaine, and lidocaine/MEGX at the four time points. However, the concentrations of ALB, ALT, AST, AST/ALT, and prothrombin time were substantially different among the four groups. Thus, we conclude that assay of MEGX in our patients with chronic viral hepatitis did not contribute to the assessment of liver function when compared with apparently healthy volunteers and traditional tests of liver function.

Prognostic value of the monoethylglycinexylidide test in pediatric liver transplant candidates.

The objective of this prospective study was to assess the prognostic value of dynamic and static liver function tests and clinical symptoms in pediatric patients with chronic end-stage liver disease in a serial examination including three evaluations at 3-month intervals. Of the 24 patients entering the study, six were given transplants within the observation period of 10 months. Of the remaining 18 patients who were considered in the final evaluation, five died before transplantation was possible. The variables included in the analysis were monoethylglycinexylidide (MEGX) formation from lidocaine, bilirubin, albumin, and creatinine serum concentrations, catalytic serum concentration of cholinesterase (CHE), prothrombin time (PT), factors II and V, serum amino acids, body weight, and presence of ascites. In nonsurvivors (n = 5), MEGX serum concentrations 30 min after intravenous administration of lidocaine (1 mg/kg body weight) were < 10 micrograms/L at the first examination. Statistically significant differences between nonsurvivors and survivors were observed for initial MEGX test results (p = 0.0089) and serum bilirubin concentrations (p = 0.009), as well as for the last available MEGX and bilirubin data from each patient (p = 0.017 and 0.016, respectively). At a diagnostic sensitivity of 100%, the corresponding diagnostic specificities for MEGX and bilirubin from the first examination were 77 and 62%, respectively. These data show that consistently low MEGX test results < 10 micrograms/L, obtained 30 min after intravenous administration of lidocaine (1 mg/kg body weight), are a prognostically unfavorable sign in pediatric transplant candidates.

Prevention of bronchoconstriction by an orally active local anesthetic.

Stimulation of airway irritant receptors produces reflex bronchoconstriction that can be prevented by pretreatment with anticholinergic drugs or local anesthetics delivered by aerosol or intravenously. We compared therapeutic doses of an orally administered local anesthetic, mexiletine hydrochloride, and intravenously administered lidocaine at blocking histamine-induced bronchoconstriction in five basenji-greyhound dogs, using high-resolution computed tomography (HRCT) to directly measure changes in airway size. In the dogs given placebo, a histamine infusion decreased airway area to 61 +/- 2% (mean +/- SEM) of control (p < 0.01). Mexiletine pretreatment completely prevented histamine-induced airway constriction, with an airway area that was 94 +/- 4% of the control value during the histamine infusion (p = 0.07 compared with baseline). Mexiletine serum levels were therapeutic (1.7 +/- 0.3 mg/L). Similarly, pretreatment with lidocaine significantly blunted the airway constriction provoked by intravenous histamine. In lidocaine-pretreated dogs, histamine decreased airway area to 79 +/- 4% of baseline (p < 0.01). As in the case of mexiletine, lidocaine serum levels were also therapeutic (2.4 +/- 0.3 mg/L). Mexiletine was more effective than lidocaine at preventing histamine-induced bronchoconstriction (p = 0.02). These data suggest that orally administered local anesthetics may be useful in preventing irritant-induced bronchoconstriction in humans.

Posterior approach to the lumbar plexus combined with a sciatic nerve block using lidocaine.

A combination of lumbar plexus block, by a posterior technique, and sciatic nerve block can be a useful technique for outpatient anaesthesia. The purpose of this study was to examine the clinical characteristics of these blocks using lidocaine and to measure the serum lidocaine concentrations. Forty-five patients, undergoing lower extremity surgery, were studied. Sciatic nerve and lumbar plexus blocks were made with lidocaine, 680 mg with adrenaline 0.3 mg. For each patient the following data were collected: weight, age, sex, site of surgery, time to perform each block, needle depth, speed of onset of the sensory and motor blocks in the territories of the sciatic, femoral, obturator and lateral cutaneous (sensory) nerves and postoperative analgesic requirements. Lidocaine serum concentrations were measured in ten of these patients at 0, 2, 5, 10, 30, 60, 90 and 120 min after the second block. Analgesia was complete in 88% (40/45) of the patients. The remaining five patients needed analgesics (fentanyl 150 micrograms or less). Despite the high dose of lidocaine, the serum concentrations were within safe limits (mean +/- SD) (CMAX = 3.66 +/- 2.21 micrograms.ml-1). Only one patient had a serum concentration > 5 micrograms.ml-1 (CMAX = 9.54 micrograms.ml-1). This was associated with a contra-lateral extension of the block. We conclude that this combination of blocks is a valuable alternative for unilateral lower extremity anaesthesia. However, clinicians must be aware of the implications of a contra-lateral extension of the block.

Change in Prescribing Patterns of Intravenous Histamine2-Receptor Antagonists Results in Significant Cost Savings without Adversely Affecting Patient Care

The cooperative efforts and educational activities associated with a major histamine2-receptor antagonist (H2RA) formulary change and the clinical and financial results are described. EVALUATION PROCESS: An extensive financial and clinical evaluation was conducted. Sources included primary literature, reference texts, institution-specific financial data, and reports of other hospitals' experiences. Through cooperative efforts with key members of the medical staff, several interventions were adopted: maintain only one parenteral H2RA on the formulary; develop guidelines for H2RA use and stress ulcer prophylaxis; investigate a target drug-reminder system to promote oral H2RA use. Within a month after implementing the formulary change and educational process, prescribing of parenteral H2RAs changed from 80 percent ranitidine to 99 percent cimetidine. Monitoring of nonformulary ranitidine use revealed only three cases of possible or probable association of adverse central nervous system effects with cimetidine in an eight-month period. Elevations of theophylline, lidocaine, or phenytoin serum concentrations; or prothrombin time above the therapeutic range during warfarin therapy occurred in only 5 of 142 monitored patients who received concomitant therapy with an H2RA. No change in serum theophylline concentrations above the therapeutic range was noted to the hospital before and after the conversion. Savings have been estimated at $250,000 in the first year and $775,000 over four years, mostly from the conversion from intravenous ranitidine to intravenous cimetidine therapy. Successful intervention can be accomplished by cooperation between the pharmacy and the medical staff to achieve cost savings without sacrificing the quality of care.

Subcutaneous lidocaine affects inducibility in programmed electrophysiology testing in children: A follow-up study

Invasive cardiac electrophysiology testing during cardiac catheterization requires local anesthesia at the point of entry for the catheters. Frequently, lidocaine is employed for this purpose. A prospective study completed in 1990 indicated that subcutaneous administration of lidocaine adversely influenced the inducibility of arrhythmias in pediatric patients. Upon completion of that study, lidocaine concentration was reduced from 1% to 0.5%, and extra caution was taken to avoid deep penetration during administration. A follow-up, prospective study was performed to evaluate inducibility under these changed conditions. Because the depressant effect of lidocaine on inducibility was age- and weight-related, the second study group was required to have statistically indistinguishable age and weight distributions from the first group to eliminate these variables as factors in inducibility. A total of 177 subjects were collected in the second group before a periodic random computer match with the first group produced 99 individuals with the required age and weight distributions. Analysis of the electrophysiology tests in the second study revealed that: (1) incidence of inducibility was higher in the second group (58 of 99 versus 43 of 99, p < 0.05); (2) average lidocaine dose per kilogram was lower (1.8 mg/kg versus 3.28 mg/kg, p < 0.0001); (3) average lidocaine serum concentration was also lower (0.58 μg/ml versus 1.47 μg/ml, p < 0.0003); (4) in contrast to the first study, neither lidocaine dose nor serum concentration had any effect on inducibility. We conclude that the new procedures for lidocaine administration effectively removed lidocaine as a factor in inducibility.