Tramadol: a review of its use in perioperative pain

Tramadol versus fentanyl during propofol-based deep sedation for uterine dilatation and curettage: a prospective study

AIM

Dilatation and curettage (D&C) is a common day-care procedure in obstetrics and gynecology, with patients discharged after a brief hospital stay on the same day of the surgery. Although it has a short duration, severe pain occurs during the procedure. Therefore, this surgical procedure requires an anesthetic to provide adequate analgesia, rapid onset, and rapid recovery. The main objective of the present study was to compare the analgesic effectiveness and safety of tramadol with those of fentanyl during D&C.

METHODS

The study comprised 100 women with American Society of Anesthesiologists classification I-II who were scheduled for a D&C procedure. Baseline anesthesia was maintained with 1 mg/kg propofol, and the patients were then randomly allocated to receive tramadol 1 mg/kg (Group T, n = 50) or fentanyl 1 μg/kg (Group F, n = 50). Hemodynamic variables, sedation, pain, the Aldrete recovery score, and side-effects were recorded.

RESULTS

SpO₂ levels in Group F in the 5th min and at the end of the procedure were significantly lower than those in Group T (P = 0.024 and 0.021, respectively).

CONCLUSION

Tramadol provides similar analgesic efficacy to fentanyl. Furthermore, tramadol may provide better respiratory stability in patients undergoing a D&C procedure.

Tramadol use in pediatric sickle cell disease patients with vaso-occlusive crisis

AIM

To evaluate whether the addition of scheduled oral tramadol to intravenous morphine and intravenous ketorolac reduces morphine requirements.

METHODS

This single-centered, Institutional Review Board-approved, retrospective study at Moses Cone Memorial Hospital included pediatric patients who were ≥ 2 years old with vaso-occlusive crisis (VOC) caused by sickle cell disease (SCD), were on morphine patient-controlled analgesia (PCA), and had scheduled oral tramadol added to their standard pain regimen. The study population was admitted between March 2008 and March 2011. The data was collected from electronic records and included age, weight, morphine use, tramadol use, hemoglobin, pain scores, number of days on PCA, length of hospital stay, respiratory rate, and polyethylene glycol use. Thirty patients were analyzed as independent admissions and seven patients as paired admissions.

RESULTS

Eighteen pediatric SCD patients with VOC received morphine PCA and intravenous ketorolac and twelve patients received morphine PCA and intravenous ketorolac and scheduled oral tramadol. Baseline characteristics were similar between both groups with the exception of the average weight, which was greater in the tramadol group than in the morphine group. The average morphine requirements in patients with and without the use of tramadol were similar, both for the independent admissions [0.58 mg/kg per day vs 0.65 mg/kg per day (P = 0.31)] and the paired admissions [0.71 mg/kg per day vs 0.77 mg/kg per day (P = 0.5)]. The daily polyethylene glycol requirement was less in the tramadol group for both the independent [0.5 g/kg per day vs 0.6 g/kg per day (P = 0.64)] and paired admissions analyses [and 0.41 g/kg per day vs 0.55 g/kg per day (P = 0.67)].

CONCLUSION

The addition of scheduled tramadol in patients receiving concomitant morphine and ketorolac demonstrates a trend toward decreased morphine and polyethylene glycol use.

Pharmacokinetics and physiological effects of repeated oral administrations of tramadol in horses

This study evaluated the pharmacokinetics and physiological effects of tramadol during repeated oral administrations in horses. Nine adult healthy horses were administered tramadol at 5 and 10 mg/kg orally every 12 h for 5 days in a randomized, crossover design with a 3-week washout between treatments. Plasma concentrations of tramadol, O- and N-desmethyltramadol (M1 and M2) were measured using Liquid-Chromatography-Mass Spectrometry at predetermined time points following each tramadol administration. Cardiovascular, respiratory and gastrointestinal physiological variables were monitored and adverse events were recorded. Data were analysed with two-way repeated measures anova or Kruskal-Wallis one-way anova on ranks with P < 0.05 considered statistically significant. There were no significant effects of tramadol on the physiological variables. One horse receiving 10 mg/kg tramadol developed mild colic. Following tramadol at 5 and 10 mg/kg, respectively, maximum plasma concentrations (Cmax ) of tramadol ranged from 82-587 and 127-1280 ng/mL, nonconjugated M1 ranged from 2.51-26.7 and 4.88-34.3 ng/mL, and nonconjugated M2 from 12.5-356 and 35.4-486 ng/mL. Corresponding minimum plasma concentrations (Cmin ) of tramadol at 12 h following each dose ranged from 0.8-24 and 3-117 ng/mL. Tramadol accumulated considerably over time, more markedly when given at 10 mg/kg than at 5 mg/kg (accumulation indexes of 3.51 and 1.73 respectively). There was no accumulation of M1 but substantial accumulation of M2. In conclusion, there was accumulation and increase in exposure to tramadol and M2, but not M1, during repeated oral administrations in horses.

Pharmacokinetics of repeated oral administration of tramadol hydrochloride in Hispaniolan Amazon parrots (Amazona ventralis)

OBJECTIVE

To determine the pharmacokinetics of tramadol hydrochloride (30 mg/kg) following twice-daily oral administration in Hispaniolan Amazon parrots (Amazona ventralis).

ANIMALS

9 healthy adult Hispaniolan Amazon parrots.

PROCEDURES

Tramadol hydrochloride was administered to each parrot at a dosage of 30 mg/kg, PO, every 12 hours for 5 days. Blood samples were collected just prior to dose 2 on the first day of administration (day 1) and 5 minutes before and 10, 20, 30, 60, 90, 180, 360, and 720 minutes after the morning dose was given on day 5. Plasma was harvested from blood samples and analyzed by high-performance liquid chromatography. Degree of sedation was evaluated in each parrot throughout the study.

RESULTS

No changes in the parrots' behavior were observed. Twelve hours after the first dose was administered, mean ± SD concentrations of tramadol and its only active metabolite M1 (O-desmethyltramadol) were 53 ± 57 ng/mL and 6 ± 6 ng/mL, respectively. At steady state following 4.5 days of twice-daily administration, the mean half-lives for plasma tramadol and M1 concentrations were 2.92 ± 0.78 hours and 2.14 ± 0.07 hours, respectively. On day 5 of tramadol administration, plasma concentrations remained in the therapeutic range for approximately 6 hours. Other tramadol metabolites (M2, M4, and M5) were also present.

CONCLUSIONS AND CLINICAL RELEVANCE

On the basis of these results and modeling of the data, tramadol at a dosage of 30 mg/kg, PO, will likely need to be administered every 6 to 8 hours to maintain therapeutic plasma concentrations in Hispaniolan Amazon parrots.

Comparison of patient-controlled analgesia versus continuous infusion of tramadol in post-cesarean section pain management

AIM

To evaluate and compare analgesic efficacy, drug consumption and patient satisfaction with the i.v. patient-controlled and continuous infusion modes of administration of tramadol.

METHODS

A total of 40 pregnant women in American Society of Anesthesiologists physical status classification system risk classes I-II scheduled for cesarean section were randomized into two groups to receive treatment in single-blind fashion. Patients in both groups received tramadol as an i.v. infusion 15 min before the end of surgery under general anesthesia for cesarean section. In the post-anesthesia care unit, the 20 patients allocated to group I were given i.v. tramadol in patient-controlled anesthesia (PCA), while the 20 other patients assigned to group II received it as a continuous infusion. Pain visual analog scores (VAS), mean arterial pressure (MAP), heart rate, total tramadol consumption, sedation scores, side-effects (nausea/vomiting) and patient satisfaction were evaluated seven times in the course of the first postoperative 24 h. The Mann-Whitney U-test and Friedman's anova were used for the statistical treatment of data.

RESULTS

VAS, sedation scores and nausea/vomiting scores were similar in both groups (P > 0.05). The 24-h tramadol consumption was significantly lower in group I (420.15 ± 66.58 mg) than in group II (494.00 ± 29.45 mg), while patient satisfaction was significantly higher in group I (P < 0.05).

CONCLUSION

While tramadol administration by either of the methods used may ensure efficient early postoperative anesthesia in cesarean section patients, i.v. PCA may be preferred because of the lower drug consumption and higher patient satisfaction associated with it.

Comparison of local anesthetic efficacy of tramadol hydrochloride (with adrenaline) versus plain tramadol hydrochloride in the extraction of upper molar teeth

PURPOSE

To evaluate the efficacy of local anesthesia using tramadol hydrochloride (HCl) with versus without adrenaline in the extraction of upper molar teeth.

PATIENTS AND METHODS

This was a double-blinded study that included 100 patients who required extraction of 1 upper molar by the conventional method and were allocated randomly into 1 of 2 groups: in group A (n = 50), each patient received an initial dose of drug A (tramadol HCl 50 mg and adrenalin 0.0225 mg diluted to 1.8 mL by distilled water); in group B (n = 50), each patient received an initial dose of drug B (tramadol HCl 50 mg diluted to 1.8 mL by distilled water). Degree of pain during tooth extraction, duration of surgery, and total number of cartridges used were recorded intraoperatively. Postoperatively, patients were instructed to record any adverse effects, such as nausea or vomiting, on the first day of the operation.

RESULTS

There were significant differences in the number of cartridges used and the degree of intraoperative pain. However, there was no significant difference in duration of surgery or side effects.

CONCLUSIONS

The results of this study suggest that tramadol HCl in combination with adrenaline can be used as an alternative local anesthetic in oral and maxillofacial surgery when, for some unusual reason, a patient cannot receive a conventional local anesthetic.

Analgesic effects of intrathecal tramadol in patients undergoing caesarean section: a randomised, double-blind study

BACKGROUND

Intrathecal tramadol combined with local anaesthetics has been used for postoperative analgesia following lower abdominal and perineal surgery. The present study evaluated the effect of intrathecal tramadol on spinal block characteristics and neonatal outcome after elective caesarean section.

METHODS

Eighty full-term parturients scheduled for elective caesarean section were randomly divided into two groups. In the fentanyl group, patients received intrathecal 0.5% bupivacaine 10 mg with fentanyl 10 μg; in the tramadol group, patients were given the same dose of bupivacaine with tramadol 10 mg. Sensory and motor block characteristics, duration of postoperative analgesia, maternal side effects, and neonatal outcome were compared.

RESULTS

One patient in the tramadol group and two patients in the fentanyl group were excluded from data analysis. Median [interquartile range] duration of postoperative analgesia in the tramadol and the fentanyl groups was 300 [240-360] min and 260 [233-300] min respectively (P = 0.02). The incidence of shivering was lower in patients who received tramadol (5%) than those who had fentanyl (32%) (P = 0.003). Apgar scores, umbilical cord acid-base measurement and neurologic and adaptive capacity scores were comparable between the two groups.

CONCLUSION

Compared to intrathecal fentanyl 10 μg, tramadol 10 mg, as an adjunct to bupivacaine for subarachnoid block for caesarean section, showed a longer duration of analgesia with a reduced incidence of shivering.

Preemptive subcutaneous tramadol for post-operative pain in lower abdomen surgeries: A randomized double blinded placebo-control study

Background:

Recently, the preemptive analgesic effects of subcutaneous infiltration of tramadol (T) in the site of incision have not been extensively studied. In this study, we investigated the effect of subcutaneous T infiltration before the incision of surgery on post-operative pain, in lower abdomen surgeries.

Materials and Methods:

This double-blind study was carried out on 90 patients (18-65 years) of American Society Anesthesiologists physical status I and II who were candidates for a lower abdomen surgery during 2011. They were randomly assigned to receive preemptive subcutaneous T or normal saline (NS). The visual analogue scale for pain (VAS) in rest and cough position and opium total dose consumption were compared between two groups in times 0, 15, 30, 60 min and 2, 4, 6, 12, 24 h after the surgery.

Results:

The VAS in cough and rest position in the first 24 h following the surgery was lower in group T (P < 0.05). Opium consumption was lower in group T (P < 0.05).

Conclusion:

Subcutaneous preemptive infiltration of T before surgical incision reduces post-operative opioid consumption.

Peripheral antinociceptive action of mangiferin in mouse models of experimental pain: role of endogenous opioids, K(ATP)-channels and adenosine

This study aimed to assess the possible systemic antinociceptive activity of mangiferin and to clarify the underlying mechanism, using the acute models of chemical (acetic acid, formalin, and capsaicin) and thermal (hot-plate and tail-flick) nociception in mice. Mangiferin at oral doses of 10 to 100 mg/kg evidenced significant antinociception against chemogenic pain in the test models of acetic acid-induced visceral pain and in formalin- and capsaicin-induced neuro-inflammatory pain, in a naloxone-sensitive manner, suggesting the participation of endogenous opiates in its mechanism. In capsaicin test, the antinociceptive effect of mangiferin (30 mg/kg) was not modified by respective competitive and non-competitive transient receptor potential vanilloid 1 (TRPV1) antagonists, capsazepine and ruthenium red, or by pretreatment with L-NAME, a non-selective nitric oxide synthase inhibitor, or by ODQ, an inhibitor of soluble guanylyl cyclase. However, mangiferin effect was significantly reversed by glibenclamide, a blocker of K(ATP) channels and in animals pretreated with 8-phenyltheophylline, an adenosine receptor antagonist. Mangiferin failed to modify the thermal nociception in hot-plate and tail-flick test models, suggesting that its analgesic effect is only peripheral but not central. The orally administered mangiferin (10-100 mg/kg) was well tolerated and did not impair the ambulation or the motor coordination of mice in respective open-field and rota-rod tests, indicating that the observed antinociception was unrelated to sedation or motor abnormality. The findings of this study suggest that mangiferin has a peripheral antinociceptive action through mechanisms that involve endogenous opioids, K(ATP)-channels and adenosine receptors.

Tramadol/Paracetamol fixed-dose combination for chronic pain management in family practice: a clinical review

The family practitioner plays an important role in the prevention, diagnosis, and early management of chronic pain. He/she is generally the first to be consulted, the one most familiar with the patients and their medical history, and is likely the first to be alerted in case of inadequate pain control or safety and tolerability issues. The family practitioner should therefore be at the center of the multidisciplinary team involved in a patient's pain management. The most frequent indications associated with chronic pain in family practice are of musculoskeletal origin, and the pain is often multimechanistic. Fixed-dose combination analgesics combine compounds with different mechanisms of action; their broader analgesic spectrum and potentially synergistic analgesic efficacy and improved benefit/risk ratio might thus be useful. A pain specialist meeting held in November 2010 agreed that the fixed-dose combination tramadol/paracetamol might be a useful pharmacological option for chronic pain management in family practice. The combination is effective in a variety of pain conditions with generally good tolerability. Particularly in elderly patients, it might be considered as an alternative to conventional analgesics such as NSAIDs, which should be used rarely with caution in this population.

A comparative study of efficacy and safety of lornoxicam versus tramadol as analgesics after surgery on head and neck

To assess efficacy and safety of lornoxicam as analgesic after surgery on head and neck in comparison to tramadol. Forty five patients undergoing operations on head and neck were recruited and randomly assigned to two parallel groups-lornoxicam and tramadol, both given intramuscular on the first post-operative day followed by oral tablets for the consecutive 4 days. Treatment was given single blind. 10 cm visual analog scale (VAS) pain score and wound tenderness assessed by a 3-point ordinal scale were the primary efficacy parameters. Use of rescue medication and percentage of subjects having at least 50 % pain relief by 48 h were also compared as secondary parameters. The groups were comparable at baseline regarding age, sex and VAS score. There was steady decline in VAS pain score from baseline to study end in both the groups, indicating good analgesic efficacy with either drug. Between groups comparisons of VAS score showed no significant difference at any time point. Between groups comparisons of wound tenderness also showed no significant difference. Five patients on lornoxicam and one patient on tramadol experienced at least 50 % pain relief at 48 hours compared to baseline while five patients from the lornoxicam group and eight from the tramadol group required rescue medicine. The tolerability of lornoxicam appeared to be significantly superior to tramadol, with less number of patients experiencing adverse drug reactions. Lornoxicam is safe, effective and comparable to tramadol for relieving postoperative pain after operations on head and neck.

The release behavior and kinetic evaluation of tramadol HCl from chemically cross linked Ter polymeric hydrogels

BACKGROUND AND THE PURPOSE OF THE STUDY

Hydrogels, being stimuli responsive are considered to be effective for targeted and sustained drug delivery. The main purpose for this work was to study the release behavior and kinetic evaluation of Tramadol HCl from chemically cross linked ter polymeric hydrogels.

METHODS

Ter-polymers of methacrylate, vinyl acetate and acrylic acid cross linked with ethylene glycol dimethacrylate (EGDMA) were prepared by free radical polymerization. The drug release rates, dynamic swelling behavior and pH sensitivity of hydrogels ranging in composition from 1-10 mol% EGDMA were studied. Tramadol HCl was used as model drug substance. The release behavior was investigated at pH 8 where all formulations exhibited non-Fickian diffusion mechanism.

RESULTS AND MAJOR CONCLUSION

Absorbency was found to be more than 99% indicating good drug loading capability of these hydrogels towards the selected drug substance. Formulations designed with increasing amounts of EGDMA had a decreased equilibrium media content as well as media penetrating velocity and thus exhibited a slower drug release rate. Fitting of release data to different kinetic models indicate that the kinetic order shifts from the first to zero order as the concentration of drug was increased in the medium, showing gradual independency of drug release towards its concentration. Formulations with low drug content showed best fitness with Higuchi model whereas those with higher concentration of drug followed Hixson-Crowell model with better correlation values indicating that the drug release from these formulations depends more on change in surface area and diameter of tablets than that on concentration of the drug. Release exponent (n) derived from Korse-Meyer Peppas equation implied that the release of Tramadol HCl from these formulations was generally non-Fickian (n > 0.5 > 1) showing swelling controlled mechanism. The mechanical strength and controlled release capability of the systems indicate that these co-polymeric hydrogels have a great potential to be used as colon drug delivery device through oral administration.

Fabrication of a new electrochemical sensor based on a new nano-molecularly imprinted polymer for highly selective and sensitive determination of tramadol in human urine samples

A new nano-molecularly imprinted polymer bead was synthesized and applied to the fabrication of a chemically modified carbon paste electrode. Nano-molecularly imprinted polymer with molecular recognition capacity was made-up by using SiO2@Fe3O4 as the core and the supporting material. The electrode was applied to the simple, rapid, highly selective and sensitive determination of tramadol using square wave voltammetry. The molecularly imprinted polymer and multi-walled carbon nanotubes modified carbon paste electrode was prepared by incorporating the synthesized nano-MIP and multi-walled carbon nanotubes in carbon paste electrode. The limit of detection and the linear range were found to be 0.004 and 0.01 to 20 μmol L(-1) of tramadol, respectively. The effects of potentially interfering substances on the determination of this compound were investigated. And it was found that the electrode is highly selective. The proposed chemically modified carbon paste electrode was used for the determination of tramadol in infected and healthy human urine and pharmaceutical samples.

Tramadol hydrochloride

A profile of the analgesic tramadol hydrochloride ((1RS,2RS)-2-[(dimethylamino)methyl]-1-(3-methoxyphenyl)cyclohexanol hydrochloride) is provided in this chapter and includes a summary of the physical characteristics known for this drug substance (e.g., UV/vis, IR, NMR, and mass spectra). Details regarding the stability of tramadol hydrochloride in the solid state and solution-phase are presented and methods of analysis (compendial and literature) are summarized. Furthermore, an account of biological properties and a description of the chemical synthesis of tramadol hydrochloride are given.

Strategies of pain reduction during the bone marrow biopsy

Examination of the bone marrow biopsy and aspirate allows diagnosis and assessment of various conditions such as primary hematologic and metastatic neoplasms, as well as nonmalignant disorders. Despite being performed for many years, according to many different protocols, the procedure still remains painful for the majority of patients. This paper summarizes the current knowledge of pain reduction measures in the bone marrow biopsy and aspiration.

Management of postoperative pain: experience of the Niamey National Hospital, Niger

OBJECTIVE

The aim of this study was to evaluate the management of postoperative pain at the Niamey National Hospital.

METHODS

A prospective study was conducted in the Department of Anesthesiology and Intensive Care at the Niamey National Hospital from March to June, 2009. Data collected included age, sex, literacy, American Society of Anesthesiologists (ASA) physical status classification, type of anesthesia, type of surgery, postoperative analgesics used, and the cost of analgesics. Three types of pain assessment scale were used depending on the patient's ability to describe his or her pain: the verbal rating scale (VRS), the numerical rating scale (NRS), or the visual analog scale (VAS). Patients were evaluated during the first 48 hours following surgery.

RESULTS

The sample included 553 patients. The VRS was used for the evaluation of 72% of patients, the NRS for 14.4%, and the VAS for 13.6%. Of the VRS group, 33.9%, 8.3%, and 2.1% rated their pain as 3 or 4 out of 4 at 12, 24, and 48 hours postoperatively, respectively. For the NRS group, 33.8%, 8.8%, and 2.5% rated their pain as greater than 7 out of 10 at 12, 24, and 48 hours postoperatively, respectively. For the VAS group, 29.3%, 5.4%, and 0% rated their pain as greater than 7 out of 10 at 12, 24, and 48 hours postoperatively, respectively.

CONCLUSION

Postoperative pain assessment and management in developing countries has not been well described. Poverty, illiteracy, and inadequate training of physicians and other health personnel contribute to the underutilization of postoperative analgesia. Analysis of the results gathered at the Niamey National Hospital gives baseline data that can be the impetus to increase training in pain management and to establish standardized protocols.

The effects of tramadol and levobupivacaine infiltration on postoperative analgesia in functional endoscopic sinus surgery and septorhinoplasty

OBJECTIVE

The aim of this prospective, randomized, double-blind study was to investigate the postoperative analgesic effects of levobupivacaine or tramadol infiltration administered prior to surgery in septorhinoplasty (SRP) or endoscopic sinus surgery (ESS).

MATERIAL AND METHODS

Sixty ASA class I-III adult patients electively undergoing SRP or ESC were included the study. Induction of anesthesia was performed with propofol 2-2.5 mg/kg, rocuronium bromide 0.6 mg/kg and fentanyl 1 μg/kg i.v. Sevoflurane 2% with an N2O/O2 mixture (FiO2: 35%) was used for maintenance. Tramadol 0.5 mg/kg (Group T: n=20), levobupivacaine 0.25% (Group L: n=20) and lidocaine 1% (Group C: n=20) in a 1/200,000 adrenaline solution was infiltrated into the surgical area 10 min before the operation (5 mL for ESS and 10 mL for SRP). All patients received fentanyl (bolus dose: 15 μg and lockout interval: 10 min) with a patient-controlled analgesia device during the postoperative period. Pain was assessed using an 11-point visual analogue scale (VAS) every 4 h for the first 24 h. Analgesic requirements, opioid consumption and side effects in the postoperative period were recorded.

RESULTS

There was a statistically significant decrease in postoperative fentanyl demand and consumption in patients receiving tramadol. Fentanyl doses in the 24 h period were 345.2±168.8 μg, 221.1±120.6 μg and 184.1±130.3 μg (p=0.002) for the Groups C, L and T, respectively. There were statistically significant differences in fentanyl requirements between the tramadol and control groups at the 16, 20 and 24 h time points (p=0.012, p=0.004 and p=0.002, respectively). The side effect profiles were similar.

CONCLUSIONS

Our study indicates that the preemptive tramadol infiltration technique is an efficient, practical and safe alternative to levobupivacaine in ESS or SRP operations.

Antinociceptive effects after oral administration of tramadol hydrochloride in Hispaniolan Amazon parrots (Amazona ventralis)

OBJECTIVE

To evaluate antinociceptive effects on thermal thresholds after oral administration of tramadol hydrochloride to Hispaniolan Amazon parrots (Amazona ventralis). Animals-15 healthy adult Hispaniolan Amazon parrots.

PROCEDURES

2 crossover experiments were conducted. In the first experiment, 15 parrots received 3 treatments (tramadol at 2 doses [10 and 20 mg/kg] and a control suspension) administered orally. In the second experiment, 11 parrots received 2 treatments (tramadol hydrochloride [30 mg/kg] and a control suspension) administered orally. Baseline thermal foot withdrawal threshold was measured 1 hour before drug or control suspension administration; thermal foot withdrawal threshold was measured after administration at 0.5, 1.5, 3, and 6 hours (both experiments) and also at 9 hours (second experiment only).

RESULTS

For the first experiment, there were no overall effects of treatment, hour, period, or any interactions. For the second experiment, there was an overall effect of treatment, with a significant difference between tramadol hydrochloride and control suspension (mean change from baseline, 2.00° and -0.09°C, respectively). There also was a significant change from baseline for tramadol hydrochloride at 0.5, 1.5, and 6 hours after administration but not at 3 or 9 hours after administration.

CONCLUSIONS AND CLINICAL RELEVANCE

Tramadol at a dose of 30 mg/kg, PO, induced thermal antinociception in Hispaniolan Amazon parrots. This dose was necessary for induction of significant and sustained analgesic effects, with duration of action up to 6 hours. Further studies with other types of noxious stimulation, dosages, and intervals are needed to fully evaluate the analgesic effects of tramadol hydrochloride in psittacines.

Pharmacokinetics after oral and intravenous administration of a single dose of tramadol hydrochloride to Hispaniolan Amazon parrots (Amazona ventralis)

OBJECTIVE

To determine pharmacokinetics after IV and oral administration of a single dose of tramadol hydrochloride to Hispaniolan Amazon parrots (Amazona ventralis).

ANIMALS

9 healthy adult Hispaniolan Amazon parrots (3 males, 5 females, and 1 of unknown sex).

PROCEDURES

Tramadol (5 mg/kg, IV) was administered to the parrots. Blood samples were collected from -5 to 720 minutes after administration. After a 3-week washout period, tramadol (10 and 30 mg/kg) was orally administered to parrots. Blood samples were collected from -5 to 1,440 minutes after administration. Three formulations of oral suspension (crushed tablets in a commercially available suspension agent, crushed tablets in sterile water, and chemical-grade powder in sterile water) were evaluated. Plasma concentrations of tramadol and its major metabolites were measured via high-performance liquid chromatography.

RESULTS

Mean plasma tramadol concentrations were > 100 ng/mL for approximately 2 to 4 hours after IV administration of tramadol. Plasma concentrations after oral administration of tramadol at a dose of 10 mg/kg were < 40 ng/mL for the entire time period, but oral administration at a dose of 30 mg/kg resulted in mean plasma concentrations > 100 ng/mL for approximately 6 hours after administration. Oral administration of the suspension consisting of the chemical-grade powder resulted in higher plasma tramadol concentrations than concentrations obtained after oral administration of the other 2 formulations; however, concentrations differed significantly only at 120 and 240 minutes after administration.

CONCLUSIONS AND CLINICAL RELEVANCE

Oral administration of tramadol at a dose of 30 mg/kg resulted in plasma concentrations (> 100 ng/mL) that have been associated with analgesia in Hispaniolan Amazon parrots.

Optimization of Carboxymethyl-Xyloglucan-Based Tramadol Matrix Tablets Using Simplex Centroid Mixture Design

The aim was to determine the release-modifying effect of carboxymethyl xyloglucan for oral drug delivery. Sustained release matrix tablets of tramadol HCl were prepared by wet granulation method using carboxymethyl xyloglucan as matrix forming polymer. HPMC K100M was used in a small amount to control the burst effect which is most commonly seen with natural hydrophilic polymers. A simplex centroid design with three independent variables and two dependent variables was employed to systematically optimize drug release profile. Carboxymethyl xyloglucan (X 1), HPMC K100M (X 2), and dicalcium phosphate (X 3) were taken as independent variables. The dependent variables selected were percent of drug release at 2nd hour (Y 1) and at 8th hour (Y 2). Response surface plots were developed, and optimum formulations were selected on the basis of desirability. The formulated tablets showed anomalous release mechanism and followed matrix drug release kinetics, resulting in regulated and complete release from the tablets within 8 to 10 hours. The polymer carboxymethyl xyloglucan and HPMC K100M had significant effect on drug release from the tablet (P > 0.05). Polynomial mathematical models, generated for various response variables using multiple regression analysis, were found to be statistically significant (P > 0.05). The statistical models developed for optimization were found to be valid.

ADP-induced platelet aggregation after addition of tramadol in vitro in fed and fasted horses plasma

Adenosine diphosphate (ADP)-induced platelet aggregation in fed and fasted horses after addition of tramadol hydrochloride was evaluated in vitro. On 10 horses citrated blood samples were collected 2h after feeding (fed animals) and 21 h after feeding (fasted animals). Final concentrations of ADP 1 and 0.5 μM, and tramadol hydrochloride (1, 15, 30, 45 and 60 min after the addition of tramadol) were used to determine the maximum degree and initial velocity of platelet aggregation. Repeated measures multifactor analysis of variance (MANOVA) was used to evaluate the effect of feeding/fasting condition, ADP concentration and addition of tramadol. Findings showed statistical differences (P≤0.05) on studied parameters after addition of tramadol to different ADP concentrations in fed and fasted horses. The clinical relevance of these results is that tramadol provides many advantages as a therapeutic option; in fact, it is an inexpensive and a relatively new analgesic in equine veterinary medicine. Further investigations would be appropriate to compare the effects of different opioids but also using different concentrations of tramadol associated with other drugs in order to have substances which can regulate the functional activity of the platelets and to extend the knowledges on equine platelet aggregation.

Effect of ketamine hydrochloride on the analgesic effects of tramadol hydrochloride in horses with signs of chronic laminitis-associated pain

OBJECTIVE

To investigate the effects of ketamine hydrochloride on the analgesic effects of tramadol hydrochloride in horses with signs of pain associated with naturally occurring chronic laminitis.

ANIMALS

15 client-owned adult horses with chronic laminitis.

PROCEDURES

Each horse received tramadol alone or tramadol and ketamine in a randomized, crossover study (≥ 2 months between treatments). Tramadol (5 mg/kg) was administered orally every 12 hours for 1 week. When appropriate, ketamine (0.6 mg/kg/h) was administered IV for 6 hours on each of the first 3 days of tramadol administration. Noninvasive systemic blood pressure values, heart and respiratory rates, intestinal sounds, forelimb load and off-loading frequency (determined via force plate system), and plasma tumor necrosis factor-α and thromboxane B(2) concentrations were assessed before (baseline) during (7 days) and after (3 days) each treatment.

RESULTS

Compared with baseline data, arterial blood pressure decreased significantly both during and after tramadol-ketamine treatment but not with tramadol alone. Forelimb off-loading frequency significantly decreased during the first 3 days of treatment with tramadol only, returning to baseline frequency thereafter. The addition of ketamine to tramadol treatment reduced off-loading frequency both during and after treatment. Forelimb load did not change with tramadol alone but increased with tramadol-ketamine treatment. Plasma concentrations of tumor necrosis factor-α and thromboxane B(2) were significantly reduced with tramadol-ketamine treatment but not with tramadol alone.

CONCLUSIONS AND CLINICAL RELEVANCE

In horses with chronic laminitis, tramadol administration induced limited analgesia, but this effect was significantly enhanced by administration of subanesthetic doses of ketamine.

Comparison of the analgesic effects of oral tramadol and naproxen sodium on pain relief during IUD insertion

OBJECTIVE

To compare the analgesic efficacy of oral tramadol and naproxen sodium on pain during insertion of an intrauterine device (IUD).

DESIGN

Randomized, double-blinded, clinical trial (Canadian Task Force classification I).

SETTING

University-affiliated hospital. Single-center.

PATIENTS

One hundred three patients scheduled for insertion of an IUD.

INTERVENTIONS

Patients were randomly assigned to receive oral tramadol 50 mg capsules (n = 35) or naproxen sodium 550 mg tablets (n = 34) or placebo (n = 34) 1 hour before insertion of the IUD. After insertion of the IUD, pain intensity was evaluated using a visual analog scale (VAS, 0-10). Adverse effects, patient satisfaction with the medication, and preference for using it during future insertions were also recorded.

MEASUREMENTS AND MAIN RESULTS

The VAS scores were significantly different during IUD insertion among the 3 groups (p = .001). Pain scores in the tramadol group were significantly lower than in the naproxen group (p = .003), and the scores in the naproxen group was significantly lower than in the control group (p = .001). Patient satisfaction with the medication and preference for its future use were significantly lower in the control group than in the other 2 groups (p = .001).

CONCLUSION

Prophylactic analgesia using 50 mg tramadol and 550 mg naproxen, delivered orally, can be used to relieve pain during IUD insertion. However, tramadol capsules were found to be more effective than naproxen tablets.

Subcutaneous administration of tramadol after elective surgery is as effective as intravenous administration in relieving acute pain and inflammation in dogs

Subcutaneous (SC) administration of tramadol was compared with intravenous (IV) administration to evaluate analgesia following canine ovariohysterectomy (OHE). Healthy female dogs (n = 12) between 1 and 3 years of age (1.95 ± 0.65 years), weighing between 10.5 and 17.1 kg (13.12 ± 1.95 kg), were used. Pain was assessed at baseline before surgery and then hourly for 8 hr after surgery. Tramadol was administered both SC and IV at a dose of 3 mg/kg and provided significant postoperative analgesia, as indicated by analgesiometry, β-endorphin levels, and interleukin 6 (IL-6) levels. The respiratory rates and rectal temperatures remained normal and were not significantly different between or within the groups. A significant increase in heart rate was observed at 4 hr for dogs in both groups relative to the baseline, but there was no significant difference in heart rates between the groups at any time point. A significant decrease in mechanical pain threshold was observed within each group after surgery, but both groups responded similarly, suggesting that SC administration of tramadol is as effective as IV administration. Increased serum levels of both IL-6 and β-endorphin 3 hr postoperatively further indicate that both routes of administration achieve similar pain control. Thus, the relative analgesic efficacy of SC tramadol is comparable to that of IV administration and can be used to achieve similar effects for postsurgical pain management in dogs undergoing OHE.

Tramadol induces conditioned place preference in rats: interactions with morphine and buprenorphine

Surveys and drug surveillance have demonstrated that the abuse liability of tramadol is considerably low in the general population but appears to be higher in opiate addicts, and this difference could attribute to the poly-drug abuse of opioid addicts, although this hypothesis has not been tested in the laboratory. The present study examined the interactions between tramadol and a full μ opioid receptor agonist morphine or a partial μ opioid receptor agonist buprenorphine in a conditioned place preference (CPP) paradigm in rats. Rats were conditioned with tramadol (2-54 mg/kg, i.p.), morphine (0.125-8 mg/kg, s.c.), buprenorphine (0.01-0.316 mg/kg, s.c.) or a combination of a subeffective dose of tramadol (2mg/kg) with a subeffective dose of morphine or buprenorphine and the CPP effect was measured. The retention of CPP effect was also examined. Tramadol, morphine and buprenorphine all produced a dose-dependent and significant CPP. A smaller dose of tramadol (2mg/kg) enhanced morphine- and buprenorphine-induced CPP and shifted the dose-effect curves of both drugs leftward. In addition, the combination of tramadol with morphine or buprenorphine prolonged the retention of CPP. These findings indicate that tramadol potentiates the rewarding effects of morphine or buprenorphine largely in an additive manner and support the general contention that tramadol has relatively low abuse liability.

Analgesic efficacy of tramadol and butorphanol in mandibular third molar surgery: a comparative study

BACKGROUND

Butorphanol tartrate, a mixed synthetic agonistantagonist opioid analgesic has been used for management of postoperative pain in minor and major surgical procedures.(14,20) Tramadol hydrochloride is a centrally acting opioid which is effectively used in postoperative pain in various minor and major surgeries.

MATERIALS AND METHODS

Twenty subjects selected randomly received butorphanol tartrate 1 mg intramuscular and 20 subjects received tramadol hydrochloride 50 mg intramuscular after the removal of mandibular third molars. Time of injection, amount of anesthetic injected, duration of surgery, adverse effects were recorded.(21)

RESULTS

The mean amount of LA administered in butorphanol group was 2.6450 ml and in tramadol group was 2.640 ml respectively, the mean duration for surgery was 56.75 and 53.5 minutes for butorphanol and tramadol groups respectively which was statistically not significant. Pain assessment was done with VAS which showed mean of 19.2 and 15.5 mm (p = 0.001) which was significant for butorphanol and tramadol respectively after 12 hours. The mean time for rescue medication requirement was 5.9 hours (for tramadol) and 8.4 hours (for butorphanol). Effective analgesic activity was seen by butorphanol 1 mg intramuscular then tramadol 50 mg.

CONCLUSION

Butorphanol 1 mg was more effective than tramadol 50 mg in respect to postoperative analgesia.

A comparison of extradural tramadol and extradural morphine for postoperative analgesia in female dogs undergoing ovariohysterectomy

PURPOSE: To compare the postoperative analgesic effects of the extradural tramadol or morphine in female dogs undergoing ovariohysterectomy. METHODS: Sixteen female dogs were randomly assigned to two groups of eight animals each and received morphine (0.1mg kg-1 M group) or tramadol (2mg kg-1 T group). The pre-anesthetic medication was intravenously (iv) acepromazine (0.05mg kg-1). Anesthesia was induced with propofol (4mg kg-1iv) and maintained with isoflurane. The degree of analgesia was evaluated using a numerical rating scale that included physiologic and behavior variables. Dogs were scored at one, three, six and 12 hours after surgery by one blinded observer. Dogs were treated with morphine (0.5mg kg-1) if their scores were >6. Serum cortisol was measured before the pre-anesthetic medication was administered (basal), at the time of the ovarian pedicle clamping (T0), and at 1 (T1), 6 (T6) and 12 (T12) hours postoperative. RESULTS: The pain score did not differ between morphine and tramadol treatments. Rescue analgesia was administered to one dog in the T treatment group. Serum cortisol did not differ between treatments. CONCLUSION: The extradural administration of morphine or tramadol is a safe and effective method of inducing analgesia in female dogs undergoing ovariohyterectomy.

Recurrent seizures in tramadol intoxication: implications for therapy based on 100 patients

Tramadol is an atypical opioid analgesic used in the treatment of mild to moderate pain. Despite being a GABA(A) agonist, seizures are a prominent complication with its therapeutic use, abuse or overdose. For patients who have had a tramadol-induced seizure, the likelihood of recurrent seizures and the need for emergent anticonvulsant prophylaxis is unknown. However, treatment of patients with anticonvulsants prophylactically may cause adverse effects and increased morbidity in tramadol poisoning. We studied the outcome and frequency of recurrent seizures in tramadol-intoxicated patients in an attempt to determine the need for prophylactic anticonvulsant therapy. This was a retrospective cohort study of tramadol-intoxicated patients who had at least one seizure. Patients' age, sex, cause(s) of intoxication, route of poisoning, dose or number of capsules or tablets taken, vital signs, other signs or symptoms, numbers of seizures, length of stay, co-ingestions and past medical history were ascertained. Exactly 100 patients met the inclusion criteria. Eighty-two per cent were men, and 50% were between 21 and 30 years old. By our standard clinical protocol, none were treated with seizure prophylaxis after their first seizure. Only 7% had recurrent seizures and all patients recovered without sequelae. Because of the low risk of multiple seizures in tramadol poisoning and the lack of morbidity in patients who do seize, it appears to be unnecessary to administer prophylactic anticonvulsant therapy in patients with tramadol poisoning, even if they have an initial seizure.

Comparative analysis of preemptive analgesic effect of tramadol chlorhydrate and nimesulide following third molar surgery

The aim of this prospective, randomized, controlled, paired trial was to perform a comparative analysis of the preemptive analgesic effect of nimesulide and tramadol chlorhydrate during third molar surgery. The study was carried out between March and November 2009, involving 94 operations in 47 male and female patients with bilateral impacted lower third molars in comparable positions. The sample was divided into two groups. Group A received an oral dose of 100 mg of nimesulide 1 h prior to surgery. Group B received an oral dose of 100 mg of tramadol chlorhydrate 1 h prior to surgery. The following aspects were evaluated in the postoperative period: adverse effects of the drugs; amount of rescue medication used (acetaminophen 750 mg); and pain 5, 6, 24, 36, 48, 60, 72 and 84 h after surgery using a visual analog pain scale. Peak pain occurred 5 h after surgery in both groups, with a mean pain score of 2.3 in Group A and 3.0 in Group B; this difference did not achieve statistical significance (p > 0.141). Based on the sample studied, nimesulide and tramadol chlorhydrate demonstrate similar preemptive analgesic effects when used in lower third molar surgeries.

Tramadol versus ketorolac in the treatment of postoperative pain following maxillofacial surgery

Pain plagues daily activity and hence its management would require alleviation at both the mental and physical planes, thus, bringing about comfort. It includes delivering analgesics in parenteral or oral form, or patches depending on the intensity and availability. Best analgesic regimens are ones that offer broad coverage, easy to administer, safe and economical. A drug seemingly appropriate to treat moderate to severe pain would be Tramadol hydrochloride, a centrally acting synthetic opioid analgesic with lower opiate-like dependence than Morphine. Ketorolac, a pyrrolo-pyrrole derivative, possesses analgesic, anti-inflammatory and anti-pyretic activity would also appear equally suitable. Fifty adult ASA grade I and II patients undergoing surgery under GA in the Department of Oral & Maxillofacial Surgery, College of Dental Sciences, Davangere, were included. Ketorolac (30 mg IM) for 25 patients and Tramadol (100 mg IM) for 25 patients were administered at the time of skin closure and repeated after 8 and 16 h from the conclusion of surgery. Pain, using the VAS at the 2nd, 4th, 6th, 12th and 24th post-operative hour, was assessed and compared using χ(2)-test. Vitals were monitored and adverse events were looked for. Though both the drugs resulted in significant decrease in pain intensity from the 2nd to 24th post-operative hour, Tramadol always resulted in better pain control than Ketorolac at every post-operative hour (P < 0.050). To conclude, intramuscular Tramadol seemed useful in controlling pain following surgery, with better levels of tolerance than intramuscular Ketorolac. However, both the drugs produced mild side effects but did not appear to influence the outcome.