It is accepted that blood phosphatidylethanol (PEth) concentrations are reliable biomarkers of et... more It is accepted that blood phosphatidylethanol (PEth) concentrations are reliable biomarkers of ethanol (alcohol) exposure. We therefore conducted a preliminary study to test the hypothesis that elevated blood PEth concentrations can help to identifying women with prenatal alcohol exposure who are at higher risk of adverse pregnancy outcomes. The study included 35 first-trimester pregnant women who self-reported alcohol ingestion and had PEth blood concentration ⩾4nM at recruitment. As a control group, 233 first-trimester pregnant women who self-reported as being either abstainers or light alcohol drinkers and had blood PEth concentrations <4nM, were also included. All participants were followed up until completion of their pregnancies. Women with prenatal alcohol exposure and PEth concentrations ⩾4nM had a risk ratio of spontaneous abortions of 3.21 (95%CI 0.93-11.06; P=0.074). Because of the potential implications in the prenatal care of women reporting risky alcohol exposure, the preliminary results from the present study indicate the need for testing the hypothesis in a more definitive approach.
Background: There is some evidence suggesting a link between paracetamol exposure and atopy in bo... more Background: There is some evidence suggesting a link between paracetamol exposure and atopy in both adults and children. Objective: We aimed to investigate whether further epidemiological support for a link between paracetamol intake and allergy could be found in a population of Mexican children. Methods: In a cross-sectional study design, we applied the ISAAC questionnaire to 3493 children aged 6
Canadian family physician Médecin de famille canadien, 2004
One of my patients is planning pregnancy and has started taking multivitamin supplements. She is ... more One of my patients is planning pregnancy and has started taking multivitamin supplements. She is experiencing gastric discomfort. What are the alternatives? Gastric discomfort is usually related to iron intake; pregnant women could use supplements with less iron. Pregnant women need 0.4 to 1.0 mg of folic acid daily. If they have a family history of neural tube defects (NTDs), insulin-dependent diabetes mellitus, or epilepsy, or are currently taking valproic acid, carbamazepine, or antifolates (eg, sulfonamides), they are at intermediate-to-high risk of having babies with NTDs and need 4.0 to 5.0 mg of folic acid daily.
Canadian family physician Médecin de famille canadien, 2006
A 36-year-old pregnant patient has symptoms of peptic disease. Treatment with diet and lifestyle ... more A 36-year-old pregnant patient has symptoms of peptic disease. Treatment with diet and lifestyle modifications and also antacids has given her little relief. If she were not pregnant, I would prescribe a proton pump inhibitor (PPI) for her. She is now 4 weeks pregnant, and I need to determine whether PPIs are safe during pregnancy. Data currently available suggest that omeprazole is not teratogenic in humans. While information on other PPIs is limited, a systematic review of the evidence suggests that they are also not teratogenic.
Canadian family physician Médecin de famille canadien, 2006
Increasing numbers of pregnant patients are treated with valproic acid, not just for epilepsy, bu... more Increasing numbers of pregnant patients are treated with valproic acid, not just for epilepsy, but also for psychiatric conditions. Are there teratogenic risks other than the risk of spina bifida? It has now become evident that valproic acid might cause more than just neural tube defects (NTDs). In a systematic review of all cohort studies intended to answer this question, higher rates of major malformations (and not just NTDs) were found in most studies. The calculated relative risk was 2.59 when compared with other antiepileptic drugs and was 3.77 when compared with risk in the general population. There is compelling evidence that the risk is dose dependent. The risks appear to begin increasing at doses of 600 mg/d and to become more prominent at doses above 1000 mg/d.
BACKGROUND: In Mexico, guidelines for fasting periods, or any audits on this topic are unavailabl... more BACKGROUND: In Mexico, guidelines for fasting periods, or any audits on this topic are unavailable, and therefore the attitudes of anesthesiologists for recommending preoperative fasting periods are unknown. MATERIAL AND METHODS: The study was a cross-sectional survey of anesthesiologists subscribed to the Annual Updated Course, organized by the Sociedad Mexicana de Anestesiologia in 2000. The response rate was 31.4%. RESULTS: Most respondents were general anesthesiologists, with 5 or more years experience in a clinical post, were working in both public and private hospitals, and were performing anesthetic procedures on both pediatric and adult patients and in both ambulatory and hospitalized patients. Approximately 23% of the respondents considered natural fruit juices to be clear liquids. For a pediatric patient ingesting breast milk 1 h before undergoing a surgical procedure, 45% thought that surgery should be delayed for 3h, followed by those delaying the surgical procedure for ...
BACKGROUND: Adverse drug reactions (ADR's) could be expected more frequently in pregnant wome... more BACKGROUND: Adverse drug reactions (ADR's) could be expected more frequently in pregnant women. This study was performed in order to identify ADR's to tocolytic drugs in hospitalised pregnant women. METHODS: A prospective cohort study was performed in two General Hospitals of the Instituto Mexicano del Seguro Social (IMSS) in Mexico City. Two hundred and seven women undergoing labor, premature labor, threatened abortion or suffering any obstetric related disease were included. Drug prescription and signs and symptoms of any potential ADR were registered daily during the hospital stay. Any potential ADR to tocolytic drugs was evaluated and classified by three of the authors using the Kramer's algorithm. RESULTS: Of the 207 patients, an ADR was positively classified in 25 cases (12.1%, CI95% 8.1 to 17.5%). All ADR's were classified as minor reactions. Grouping patients with diagnosis of threatened abortion, premature labor or under labor (n= 114), 24 ADR's were rel...
We are reporting the case of a woman with 8 weeks of amenorrhea who orally received a single dose... more We are reporting the case of a woman with 8 weeks of amenorrhea who orally received a single dose of misoprostol 400 microg at midnight for ripening of cervix before uterine evacuation of an intrauterine gestational sac containing a single fetus (6.3 weeks of gestation) without cardiac activity. The patient had severe abdominal pain an hour later. Her blood pressure was 70/40 mmHg and her abdomen was slightly distended with direct and rebound tenderness. A transvaginal ultrasonography showed a 3-cm depth of a free fluid collection in the rectouterine pouch. Her hemoglobin and hematocrit levels were of 6.5 g/dL and 18.4%, respectively. A rupture of 1.5 cm at the left uterine horn with a protruding gestational sac was identified by laparoscopy. The gestational sac was removed and hemoperitoneal collection were successfully drained. The site of uterine rupture was primarily sutured and postoperative course was satisfactory. In summary, misoprostol administered in the first trimester of pregnancy may produce uterine rupture.
Using a mathematical approach, we analyzed the behavior of the PD model originally described by B... more Using a mathematical approach, we analyzed the behavior of the PD model originally described by Bragg et al. The effect was dose-dependent modified until a maximum value (E(max)) was reached. Further increments in dose prolonged the E(max), but the recovery phase did not increase beyond a calculable asymptope. In the absence of plasma concentrations, it was impossible to distinguish the rate of plasma equilibration with the effect compartment (k(e0)) from the rate of drug elimination (k(e1)). Variations on the sigmoidicity affected both the onset and offset of drug effect. Sigmoidicity and the slowest rate constant had identical effects on the spontaneous reversion of the effect, as judged by the recovery index. The IR(50), the index of potency, merely shifted the dose-response relationship to the left or right. Changes in IR(50) were compensated for by making the same proportional changes in dose.
Journal of Chromatography B: Biomedical Sciences and Applications, 1999
Simplified reversed-phase high-performance liquid chromatographic method with ultraviolet detecti... more Simplified reversed-phase high-performance liquid chromatographic method with ultraviolet detection at 280 nm without extraction procedure is described to quantify furosemide in rabbit and human urine. An internal standard was not used. The lower limit of quantitation was 0.750 microg/ml using 50 microl urine samples (100 microl of total injection volume), and linear response was tested from 0.750 to 250 microg/ml in both humans and rabbits. Within and between-day accuracy and precision were always below 10% at all analyzed concentrations. Validation data showed that this method is linear, sensitive, selective, specific, accurate and reproducible.
Infection is the most common complication and cause of failure of cerebrospinal fluid (CSF) shunt... more Infection is the most common complication and cause of failure of cerebrospinal fluid (CSF) shunt devices used to control hydrocephalus. A male newborn was admitted for treatment of congenital occlusive hydrocephalus by means of a ventriculo-peritoneal shunt. A day later, the skin area around the site of insertion of ventriculo-peritoneal catheter was red and edematous. Intravenous ceftazidime and vancomycin were initiated. The shunt was removed but the external ventricular drain was preserved. Blood and CSF cultures showed Enterococcus faecalis sensitive to vancomycin, ciprofloxacin and gentamicin, but resistant to ampicillin. Intraventricular administration of vancomycin 10 mg/24 h was initiated through the external ventricular drain. Before the first dose of vancomycin intraventricularly, CSF levels were 19 mg/dL as a result of administration. On the third day of intraventricular dosing, vancomycin levels in CSF reached 388 mg/dL and protein levels were 1160 mg/dL. On the fifth day of intraventricular treatment the patient had clinically improved and was bacteriologically cured. However, in CSF, protein levels were 3300 mg/dL and vancomycin levels 201 mg/dL. In an attempt to prevent high and potentially toxic levels in CSF, the intraventricular dose of vancomycin should be individualized according to clinical response, bacteriological cultures, vancomycin levels in CSF, and surrogate markers of neurotoxicity, that is, eosinophilia and high protein levels in CSF.
Ketorolac is a potent analgesic drug that has been restricted in dosage and use because of its po... more Ketorolac is a potent analgesic drug that has been restricted in dosage and use because of its potential adverse effects. The diagnostic and ethical challenges of 2 children who had unpredictable adverse drug reactions to ketorolac are reported. Case 1: A 3-year-old boy received ketorolac 1 mg/kg for prevention of postoperative pain at the end of an orthopedic surgical procedure. Ten minutes later, he had bilateral palpebral edema, erythema in thorax, hypotension, and tachycardia. The adverse event was classified as a mixed reaction probably related to ketorolac. Case 2: A 7-year-old girl, who had previously received ketorolac in 2 different surgical procedures, underwent a third orthopedic surgery. She received ketorolac 1 mg/kg as pre-emptive analgesia at 1.5 hours of anesthetic time (approximately 1 hour of surgical time). The patient developed palpebral edema 5 minutes later in addition to erythema in thorax, hypotension, tachycardia, tachypnea, oxygen desaturation, and wheezing. The adverse event was classified as a systemic reaction probably related to ketorolac. The 2 patients were successfully treated with symptomatic therapy. Although rare in its frequency, ketorolac administration may be associated to anaphylactic and anaphylactoid reactions in children with or without history of previous exposure. Because ketorolac is off-licensed for pediatric patients, it should be administered only after the risks and benefits have been discussed with the child's parents in the preanesthetic consultation.
It is accepted that blood phosphatidylethanol (PEth) concentrations are reliable biomarkers of et... more It is accepted that blood phosphatidylethanol (PEth) concentrations are reliable biomarkers of ethanol (alcohol) exposure. We therefore conducted a preliminary study to test the hypothesis that elevated blood PEth concentrations can help to identifying women with prenatal alcohol exposure who are at higher risk of adverse pregnancy outcomes. The study included 35 first-trimester pregnant women who self-reported alcohol ingestion and had PEth blood concentration ⩾4nM at recruitment. As a control group, 233 first-trimester pregnant women who self-reported as being either abstainers or light alcohol drinkers and had blood PEth concentrations <4nM, were also included. All participants were followed up until completion of their pregnancies. Women with prenatal alcohol exposure and PEth concentrations ⩾4nM had a risk ratio of spontaneous abortions of 3.21 (95%CI 0.93-11.06; P=0.074). Because of the potential implications in the prenatal care of women reporting risky alcohol exposure, the preliminary results from the present study indicate the need for testing the hypothesis in a more definitive approach.
Background: There is some evidence suggesting a link between paracetamol exposure and atopy in bo... more Background: There is some evidence suggesting a link between paracetamol exposure and atopy in both adults and children. Objective: We aimed to investigate whether further epidemiological support for a link between paracetamol intake and allergy could be found in a population of Mexican children. Methods: In a cross-sectional study design, we applied the ISAAC questionnaire to 3493 children aged 6
Canadian family physician Médecin de famille canadien, 2004
One of my patients is planning pregnancy and has started taking multivitamin supplements. She is ... more One of my patients is planning pregnancy and has started taking multivitamin supplements. She is experiencing gastric discomfort. What are the alternatives? Gastric discomfort is usually related to iron intake; pregnant women could use supplements with less iron. Pregnant women need 0.4 to 1.0 mg of folic acid daily. If they have a family history of neural tube defects (NTDs), insulin-dependent diabetes mellitus, or epilepsy, or are currently taking valproic acid, carbamazepine, or antifolates (eg, sulfonamides), they are at intermediate-to-high risk of having babies with NTDs and need 4.0 to 5.0 mg of folic acid daily.
Canadian family physician Médecin de famille canadien, 2006
A 36-year-old pregnant patient has symptoms of peptic disease. Treatment with diet and lifestyle ... more A 36-year-old pregnant patient has symptoms of peptic disease. Treatment with diet and lifestyle modifications and also antacids has given her little relief. If she were not pregnant, I would prescribe a proton pump inhibitor (PPI) for her. She is now 4 weeks pregnant, and I need to determine whether PPIs are safe during pregnancy. Data currently available suggest that omeprazole is not teratogenic in humans. While information on other PPIs is limited, a systematic review of the evidence suggests that they are also not teratogenic.
Canadian family physician Médecin de famille canadien, 2006
Increasing numbers of pregnant patients are treated with valproic acid, not just for epilepsy, bu... more Increasing numbers of pregnant patients are treated with valproic acid, not just for epilepsy, but also for psychiatric conditions. Are there teratogenic risks other than the risk of spina bifida? It has now become evident that valproic acid might cause more than just neural tube defects (NTDs). In a systematic review of all cohort studies intended to answer this question, higher rates of major malformations (and not just NTDs) were found in most studies. The calculated relative risk was 2.59 when compared with other antiepileptic drugs and was 3.77 when compared with risk in the general population. There is compelling evidence that the risk is dose dependent. The risks appear to begin increasing at doses of 600 mg/d and to become more prominent at doses above 1000 mg/d.
BACKGROUND: In Mexico, guidelines for fasting periods, or any audits on this topic are unavailabl... more BACKGROUND: In Mexico, guidelines for fasting periods, or any audits on this topic are unavailable, and therefore the attitudes of anesthesiologists for recommending preoperative fasting periods are unknown. MATERIAL AND METHODS: The study was a cross-sectional survey of anesthesiologists subscribed to the Annual Updated Course, organized by the Sociedad Mexicana de Anestesiologia in 2000. The response rate was 31.4%. RESULTS: Most respondents were general anesthesiologists, with 5 or more years experience in a clinical post, were working in both public and private hospitals, and were performing anesthetic procedures on both pediatric and adult patients and in both ambulatory and hospitalized patients. Approximately 23% of the respondents considered natural fruit juices to be clear liquids. For a pediatric patient ingesting breast milk 1 h before undergoing a surgical procedure, 45% thought that surgery should be delayed for 3h, followed by those delaying the surgical procedure for ...
BACKGROUND: Adverse drug reactions (ADR's) could be expected more frequently in pregnant wome... more BACKGROUND: Adverse drug reactions (ADR's) could be expected more frequently in pregnant women. This study was performed in order to identify ADR's to tocolytic drugs in hospitalised pregnant women. METHODS: A prospective cohort study was performed in two General Hospitals of the Instituto Mexicano del Seguro Social (IMSS) in Mexico City. Two hundred and seven women undergoing labor, premature labor, threatened abortion or suffering any obstetric related disease were included. Drug prescription and signs and symptoms of any potential ADR were registered daily during the hospital stay. Any potential ADR to tocolytic drugs was evaluated and classified by three of the authors using the Kramer's algorithm. RESULTS: Of the 207 patients, an ADR was positively classified in 25 cases (12.1%, CI95% 8.1 to 17.5%). All ADR's were classified as minor reactions. Grouping patients with diagnosis of threatened abortion, premature labor or under labor (n= 114), 24 ADR's were rel...
We are reporting the case of a woman with 8 weeks of amenorrhea who orally received a single dose... more We are reporting the case of a woman with 8 weeks of amenorrhea who orally received a single dose of misoprostol 400 microg at midnight for ripening of cervix before uterine evacuation of an intrauterine gestational sac containing a single fetus (6.3 weeks of gestation) without cardiac activity. The patient had severe abdominal pain an hour later. Her blood pressure was 70/40 mmHg and her abdomen was slightly distended with direct and rebound tenderness. A transvaginal ultrasonography showed a 3-cm depth of a free fluid collection in the rectouterine pouch. Her hemoglobin and hematocrit levels were of 6.5 g/dL and 18.4%, respectively. A rupture of 1.5 cm at the left uterine horn with a protruding gestational sac was identified by laparoscopy. The gestational sac was removed and hemoperitoneal collection were successfully drained. The site of uterine rupture was primarily sutured and postoperative course was satisfactory. In summary, misoprostol administered in the first trimester of pregnancy may produce uterine rupture.
Using a mathematical approach, we analyzed the behavior of the PD model originally described by B... more Using a mathematical approach, we analyzed the behavior of the PD model originally described by Bragg et al. The effect was dose-dependent modified until a maximum value (E(max)) was reached. Further increments in dose prolonged the E(max), but the recovery phase did not increase beyond a calculable asymptope. In the absence of plasma concentrations, it was impossible to distinguish the rate of plasma equilibration with the effect compartment (k(e0)) from the rate of drug elimination (k(e1)). Variations on the sigmoidicity affected both the onset and offset of drug effect. Sigmoidicity and the slowest rate constant had identical effects on the spontaneous reversion of the effect, as judged by the recovery index. The IR(50), the index of potency, merely shifted the dose-response relationship to the left or right. Changes in IR(50) were compensated for by making the same proportional changes in dose.
Journal of Chromatography B: Biomedical Sciences and Applications, 1999
Simplified reversed-phase high-performance liquid chromatographic method with ultraviolet detecti... more Simplified reversed-phase high-performance liquid chromatographic method with ultraviolet detection at 280 nm without extraction procedure is described to quantify furosemide in rabbit and human urine. An internal standard was not used. The lower limit of quantitation was 0.750 microg/ml using 50 microl urine samples (100 microl of total injection volume), and linear response was tested from 0.750 to 250 microg/ml in both humans and rabbits. Within and between-day accuracy and precision were always below 10% at all analyzed concentrations. Validation data showed that this method is linear, sensitive, selective, specific, accurate and reproducible.
Infection is the most common complication and cause of failure of cerebrospinal fluid (CSF) shunt... more Infection is the most common complication and cause of failure of cerebrospinal fluid (CSF) shunt devices used to control hydrocephalus. A male newborn was admitted for treatment of congenital occlusive hydrocephalus by means of a ventriculo-peritoneal shunt. A day later, the skin area around the site of insertion of ventriculo-peritoneal catheter was red and edematous. Intravenous ceftazidime and vancomycin were initiated. The shunt was removed but the external ventricular drain was preserved. Blood and CSF cultures showed Enterococcus faecalis sensitive to vancomycin, ciprofloxacin and gentamicin, but resistant to ampicillin. Intraventricular administration of vancomycin 10 mg/24 h was initiated through the external ventricular drain. Before the first dose of vancomycin intraventricularly, CSF levels were 19 mg/dL as a result of administration. On the third day of intraventricular dosing, vancomycin levels in CSF reached 388 mg/dL and protein levels were 1160 mg/dL. On the fifth day of intraventricular treatment the patient had clinically improved and was bacteriologically cured. However, in CSF, protein levels were 3300 mg/dL and vancomycin levels 201 mg/dL. In an attempt to prevent high and potentially toxic levels in CSF, the intraventricular dose of vancomycin should be individualized according to clinical response, bacteriological cultures, vancomycin levels in CSF, and surrogate markers of neurotoxicity, that is, eosinophilia and high protein levels in CSF.
Ketorolac is a potent analgesic drug that has been restricted in dosage and use because of its po... more Ketorolac is a potent analgesic drug that has been restricted in dosage and use because of its potential adverse effects. The diagnostic and ethical challenges of 2 children who had unpredictable adverse drug reactions to ketorolac are reported. Case 1: A 3-year-old boy received ketorolac 1 mg/kg for prevention of postoperative pain at the end of an orthopedic surgical procedure. Ten minutes later, he had bilateral palpebral edema, erythema in thorax, hypotension, and tachycardia. The adverse event was classified as a mixed reaction probably related to ketorolac. Case 2: A 7-year-old girl, who had previously received ketorolac in 2 different surgical procedures, underwent a third orthopedic surgery. She received ketorolac 1 mg/kg as pre-emptive analgesia at 1.5 hours of anesthetic time (approximately 1 hour of surgical time). The patient developed palpebral edema 5 minutes later in addition to erythema in thorax, hypotension, tachycardia, tachypnea, oxygen desaturation, and wheezing. The adverse event was classified as a systemic reaction probably related to ketorolac. The 2 patients were successfully treated with symptomatic therapy. Although rare in its frequency, ketorolac administration may be associated to anaphylactic and anaphylactoid reactions in children with or without history of previous exposure. Because ketorolac is off-licensed for pediatric patients, it should be administered only after the risks and benefits have been discussed with the child's parents in the preanesthetic consultation.
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Papers by Alejandro Nava-Ocampo