Receptors involved in dexketoprofen analgesia in murine visceral pain.

Various animal models, especially rodents, are used to study pain, due to the difficulty of studying it in humans. Many drugs that produce analgesia have been studied and there is evidence among which NSAIDs deserve to be highlighted. Dexketoprofen (DEX) provides a broad antinociceptive profile in different types of pain; therefore, this study was designed to evaluate the profile of antinociceptive potency in mice. Analgesic activity was evaluated using the acetic acid abdominal constriction test (writhing test), a chemical model of visceral pain. Dose-response curves for i.p. DEX administration (1, 3, 10, 30 and 100 mg/kg), using at least six mice in each of at least five doses, was obtained before and 30 min after pre-treatment with different pharmacological agents. Pretreatment of the mice with opioid receptor antagonists was not effective; however, the serotonin receptor antagonist and nitric oxide synthase inhibitor produce a significant increase in DEX-induced antinociception. The data from the present study shows that DEX produces antinociception in the chemical twisting test of mice, which is explained with difficulty by the simple inhibition of COX. This effect appears to be mediated by other mechanisms in which the contribution of the NO and 5-HT pathways has an important effect on DEXinduced antinociception.

Interleukin-1beta in synergism gabapentin with tramadol in murine model of diabetic neuropathy.

Neuropathic pain is a complication of cancer and diabetes mellitus and the most commonly used drugs in the treatment of the diabetic neuropathic pain have only limited efficacy. The aim of this study was to evaluate the role of the biomarker interleukin-1beta (IL-1ß) in the pharmacological interaction of gabapentin with tramadol in a model of diabetic neuropathic pain. CF-1 male mice, pretreated with 200 mg/kg i.p. of streptozocin (STZ), were used and at day 3 and 7 were evaluated by the hot plate test and the spinal cord level of IL-1ß was determined. Antinociceptive interaction of the coadministration i.p. of gabapentin with tramadol, in basic of the fixed the ratio 1:1 of their ED50 values alone, was ascertained by isobolographic analysis. Tramadol was 1.13 times more potent than gabapentin in saline control mice, 1.40 times in STZ mice at 3 days and 1.28 times in STZ at 7 days. The interaction between gabapentin and tramadol was synergic, with an interaction index of 0.30 and 0.22 for mice pretreated with STZ at 3 and 7 days. The combination of gabapentin with tramadol reversed the increased concentration of IL-1ß induced by STZ in diabetic neuropathic mice. These findings could help clarify the mechanism of diabetic neuropathy.

Antinociceptive interaction of gabapentin with minocycline in murine diabetic neuropathy.

OBJECTIVE: Diabetic neuropathy (DN) is the most common complication of diabetes and pain is one of the main symptoms of diabetic neuropathy, however, currently available drugs are often ineffective and complicated by adverse events. The purpose of this research was to evaluate the antinociceptive interaction between gabapentin and minocycline in a mice experimental model of DN by streptozocin (STZ). METHODS: The interaction of gabapentin with minocycline was evaluated by the writhing and hot plate tests at 3 and 7 days after STZ injection or vehicle in male CF1 mice. RESULTS: STZ (150 mg/kg, i.p.) produced a marked increase in plasma glucose levels on day 7 (397.46 ± 29.65 mg/dL) than on day 3 (341.12 ± 35.50 mg/dL) and also developed neuropathic pain measured by algesiometric assays. Gabapentin produced similar antinociceptive activity in both writhing and hot plate tests in mice pretreated with STZ. However, minocycline was more potent in the writhing than in the hot plate test in the same type of mice. The combination of gabapentin with minocycline produced synergistic interaction in both test. CONCLUSION: The combination of gabapentin with minocycline in a 1:1 proportion fulfills all the criteria of multimodal analgesia and this finding suggests that the combination provide a therapeutic alternative that could be used for human neuropathic pain management.

Evaluation of TSH Levels in the Program of Congenital Hypothyroidism Newborn Screening in a Pilot Study of Preterm Newborns in Bogotá, Colombia

Abstract Introduction: Preterm infants (<37 weeks of gestation) have low levels of thyroid hormones due to multiple factors. Objective: To evaluate levels of thyroid-stimulation hormone (TSH) in the program congenital hypothyroidism (CH) newborn screening in a sample of preterm infants in the city of Bogotá, Colombia. Methods: The Secretaría de Salud Distrital screening protocol for CH (blood sample is collected from the umbilical cord in all the newborns) remeasured the serum TSH and heel TSH when preterm infants completed 37 weeks of gestation. Results: A total of 59 preterm neonates were rescreened, of which 2 neonates had elevated levels of TSH and 1 neonate had transient hypothyroxinemia. The Kolmogorov-Smirnov 2-sample/bilateral statistical test was used to compare the neonatal TSH levels of preterm and full-term newborns, which do not follow the same distribution. Conclusion: In our pilot study, 2 of the rescreened infants presented high levels of TSH and 1 had transient hyperthyrotropinemia, suggesting the need for rescreening of preterm infants. Additionally, a larger study should be performed to determine the screening cutoff values for preterm newborns.

Antinociception induced by atorvastatin in different pain models.

Atorvastatin is a statin that inhibits the 3-hydroxy-methyl-glutaryl coenzyme A (HMG-CoA) reductase. Several landmark clinical trials have demonstrated the beneficial effects of statin therapy for primary and secondary prevention of cardiovascular disease. It is assumed that the beneficial effects of statin therapy are entirely due to cholesterol reduction. Statins have an additional activity (pleiotropic effect) that has been associated to their anti-inflammatory effects. The aim of the present study was to assess the antinociceptive activity of atorvastatin in five animal pain models. The daily administration of 3-100mg/kg of atorvastatin by oral gavage induced a significant dose-dependent antinociception in the writhing, tail-flick, orofacial formalin and formalin hind paw tests. However, this antinociceptive activity of atorvastatin was detectable only at high concentrations in the hot plate assay. The data obtained in the present study demonstrates the effect of atorvastatin to reduce nociception and inflammation in different animal pain models.

Interaction between dexibuprofen and dexketoprofen in the orofacial formalin test in mice.

Animal models are used to research the mechanisms of pain and to mimic human pain. The purpose of this study was to determine the degree of interaction between dexketoprofen and dexibuprofen, by isobolographic analysis using the formalin orofacial assay in mice. This assay presents two-phase time course: an early short-lasting, phase I, starting immediately after the formalin injection producing a tonic acute pain, leaving a 15 min quiescent period, followed by a prolonged, phase II, after the formalin and representing inflammatory pain. Administration of dexketoprofen or dexibuprofen produced a dose-dependent antinociception, with different potency, either during phases I or II. The co-administration of dexketoprofen and dexibuprofen produced synergism in phase I and II. In conclusion, both dexketoprofen and dexibuprofen are able to induce antinociception in the orofacial formalin assay. Their co-administration produced a synergism, which could be related to the different degree of COX inhibition and other mechanisms of analgesics.

Synergism between COX-3 inhibitors in two animal models of pain.

OBJECTIVE AND DESIGN: The antinociception induced by the intraperitoneal coadministration in mice of combinations of metamizol and paracetamol was evaluated in the tail flick test and orofacial formalin test. METHODS: The antinociception of each drugs alone and the interaction of the combinations was evaluated by isobolographic analysis in the tail-flick and in the formalin orofacial assay of mice. RESULTS: Mice pretreated with the drugs demonstrated that the antinociception of metamizol and paracetamol is dose-dependent. The potency range on the antinocifensive responses for metamizol or paracetamol was as follows: orofacial (Phase II) > orofacial (Phase I) > tail flick. In addition, the coadministration of metamizol with paracetamol induced a strong synergistic antinociception in the algesiometer assays. Both drugs showed effectiveness in inflammatory pain. CONCLUSION: These actions can be related to the differential selectivity of the drugs for inhibition of COX isoforms and also to the several additional antinociception mechanisms and pathways initiated by the analgesic drugs on pain transmission. Since the efficacy of the combination of metamizol with paracetamol has been demonstrated in the present study, this association could have a potential beneficial effect on the pharmacological treatment of clinical pain.

Effects of tramadol and dexketoprofen on analgesia and gastrointestinal transit in mice.

The purpose of the present study was to evaluate the nature of the antinociceptive interaction among dexketoprofen (DEX), a mixed inhibitor of the cyclo-oxygenases, and tramadol (TRAM), a weak opioid with monoaminergic activity that inhibits norepinephrine and serotonin re-uptake. We assessed antinociception in the acetic acid writhing test, the tail flick and the formalin (FT) tests, and gastrointestinal transit (GIT) after the administration of a charcoal meal. The analysis of the interaction was carried out using isobolograms and interaction indexes or the fixed-dose method GIT. The administration of DEX or TRAM individually induced dose-dependent antinociception in all the algesiometric tests. In the three tests, TRAM was between 5.2 (FT, phase I) and 35 times (FT, Phase II) more potent than DEX. When testing combinations at different potency ratios (1 : 1, 1 : 3, 3 : 1), we could demonstrate synergy in all algesiometric tests, only when drugs were combined in a 1 : 1 proportion. Interestingly, the proportion of the drugs in the combination could change the type of interaction from synergy to antagonism. On the inhibition of GIT, a dose-related inhibition was established for TRAM, but not for DEX. Using a fixed-dose protocol, we could demonstrate antagonism between DEX and TRAM on the inhibition of GIT. The results of the present study suggest that a combination of DEX and TRAM in a 1 : 1 proportion could be adequate to use in future clinical trials in humans.

Synergism between NSAIDs in the orofacial formalin test in mice.

Opioids and non-steroidal anti-inflammatory drugs (NSAIDs) are used to relieve acute and chronic pain. The purpose of this study was to determine the degree of interaction between dexketoprofen and NSAID examples of COXs inhibitors using the isobolographic analysis in the formalin orofacial test in mice. The drugs, i.p., induced a dose-dependent antinociception with different potencies in both test phases. Combinations of dexketoprofen with naproxen, nimesulide, ibuprofen or paracetamol on the basis of the fixed ratio (1:1) of their ED(50)'s values alone demonstrated synergism in both phases. This is important since the orofacial pain is a test not currently used in mice; the drugs are all analgesic for humans and phase II is representative of inflammatory pain. The synergism was: COX-3>COX-2>COX-1 inhibitors, this is particularly interesting since the inhibitor of COX-3, paracetamol, displayed a robust anti-inflammatory activity in an assay of acute and inflammatory pain that mimics inflammatory pain in humans. In conclusion, the synergism of the dexketoprofen/NSAID combinations may improve this type of therapeutic profile, since with low doses of the components, side effects are not likely to occur, and they may be used in long-term treatments.

Trombosis en el infarto agudo del miocardio en hospitales chilenos: la experiencia del grupo GEMI / Thrombolysis in the acute myocardial infarction in chilean hospitals: the gemi group experience

Antecedentes: La trombolisis es uno de los métodos de reperfusión coronaria que permite reducir la mortalidad del infarto agudo del miocardio (IAM). Lamentablemente no todos los pacientes con indicación de trombolítico reciben el tratamiento. Objetivo: Evaluar los cambios en el empleo de trombolíticos a través del tiempo en pacientes con IAM y supradesnivel ST y analizar las variaciones en mortalidad según el período de registro. Método: Se compara la información de tres registros efectuados los años 93-95 (R1), 97-98 (R2), y los pacientes incluidos en el año 2001 del registro GEMI actualmente en curso (R3), en el que participan 23 hospitales de Santiago y regiones. Se recolecto información sobre latencia en administración del trombolítico, motivo de la no utilización y evolución intrahospitalaria de los pacientes que ingresaron con el diagnóstico de IAM Q o con supradesnivel ST (SDST). Resultados: En R1 se recolectaron 2.155 pacientes con IAM y SDST, en R2: 1.436 pacientes y en R3: 789 pacientes. El porcentaje que recibió trombolíticos fue de 37,8 por ciento, 41,4 por ciento y 45,1 por ciento, respectivamente. La mortalidad global en cada uno de los registros fue de R1: 11,2 por ciento, R2: 9,9 por ciento y R3: 8,9 por ciento ( p para tendencias: NS). Cuando se analiza según sexo, la mortalidad en hombres fue de 8,1 por ciento 7,4 por ciento y 7,1 por ciento (p para tendencias: NS). En mujeres estas proporciones fueron 23,6 por ciento 19,2 por ciento y 14,8 por ciento, respectivamente (p para tendencias: <0,05). El motivo de no uso trombolítico, dato consignado en R2 y R3, se debió a: ingreso tardío (45 por ciento y 38 por ciento respectivamente), contraindicación (9,5 y 12,5), no disponibilidad de él (1,5 por ciento y 0,23 por ciento). En el resto de los pacientes se consignó como “otro” el motivo de no uso. (De este análisis se excluyeron los pacientes sometidos a angioplastia primaria). Se observa un aumento en la proporción de pacientes sometidos a trombosis, asociado a una reducción en la mortalidad global en ellos. Conclusión: La reducción de la mortalidad en mujeres es determinante en la mejoría del pronóstico intrahospitalario en la población de trombolisados. Estos hallazgos pueden reflejar una mejor indicación y oportunidad del empleo de trombolíticos, así como de los fármacos de eficacia demostrada para el tratamiento de IAM con SDST...

[Cardiovascular risk factors in middle-age women with acute coronary syndromes]. / Impacto de los factores de riesgo coronario en mujeres de edad media.

BACKGROUND: In Chile, 40% of deaths due to acute myocardial infarction occur in women. AIM: To assess the presence of cardiovascular risk factors in women with acute coronary syndromes. PATIENTS AND METHODS: Thirty four women aged 46 to 55 years old, admitted to the hospital due to an acute coronary syndrome and 102 age matched healthy women were studied. A clinical history was obtained, blood pressure and fasting serum lipids were measured. RESULTS: A history of high blood pressure was present in 65 and 16% of patients and healthy controls respectively. Seventy seven percent of patients and 36% of controls smoked, 76% of patients and 48% of controls were postmenopausal, 21% of patients an 5% of controls were diabetic. In patients and controls respectively serum total cholesterol was 230.1 +/- 36.2 and 211.2 +/- 34.8 mg/dl, serum triacylglycerol was 213.4 +/- 109.4 and 143.2 +/- 76.9 mg/dl and serum HDL cholesterol was 44.1 +/- 10.8 and 49.8 +/- 13.3 mg/dl (p < 0.001 or less). In univariate analysis, the risk of acute coronary syndrome increased with high blood pressure (OR: 9.3, CI: 2.5-18.6), menopause (OR: 8.3, CI: 2.2-31:5), smoking (OR: 6.9, CI: 2.5-18.6), diabetes mellitus (OR: 5.0, CI: 1.4-17.5), a high total cholesterol/HDL cholesterol ratio (OR: 6.6, CI: 1.8-12.5) and hypertriglyceridemia (OR: 3.6, CI: 1.5-8.5). Logistic regression analysis showed that hypertension and menopause had the higher predictive values for acute coronary syndrome. CONCLUSIONS: In this group of women with acute coronary syndromes, the main coronary risk factors were high blood pressure and menopause.

[Changes in the patterns of drug prescription for acute myocardial infarct. Comparison of 2 periods]. / Cambios en los patrones de prescripción de medicamentos en el infarto agudo del miocardio. Comparación de dos períodos.

BACKGROUND: Pharmacotherapy of Chilean patients with acute myocardial infarction has been recorded in 37 hospitals since 1993. AIM: To compare pharmacotherapy for acute myocardial infarction in the period 1993 to 1995 with the period 1997-1998. PATIENTS AND METHODS: Drug prescription during hospital stay was recorded in 2957 patients admitted to Chilean hospitals with an acute myocardial infarction in the period 1993-1995 and compared with that of 1981 subjects admitted in the period 1997-1998. RESULTS: When compared with the former period, in the lapse 1997-1998 there was an increase in the frequency of prescription of aspirin (93 and 96.1% respectively) beta blockers (37 and 55.2% respectively) and angiotensin converting enzyme inhibitors (32 and 53%). The prescription of thrombolytic therapy did not change (33 and 33.7% respectively). There was a reduction in the prescription of calcium antagonists and antiarrhythmic drugs. CONCLUSIONS: During the period 1997-1998, the prescription of drugs with a potential to reduce the mortality of acute myocardial infarction, increased. The diffusion of guidelines for the management of this disease may have influenced this change.

[Safety profile of statins]. / El perfil de seguridad de las estatinas.

HMG-CoA reductase inhibitors (statins) are the treatment of choice for patients with hypercholesterolaemia. Several large-scale clinical trials have examined the efficacy and tolerability of statins, providing a wealth of information on their safety and adverse effect profile. Adverse hepatic effect is reflected as asymptomatic elevations in serum levels of aminotransaminases. Myopathy, occasionally leading to myoglobulinuria secondary to rhabdomyolysis, is a rare and potentially fatal complication. Cerivastatin, the last statin approved for use in humans, was voluntarily withdrawn from the market by Bayer, because fatal rhabdomyolysis was most frequently reported with cerivastatin than for other approved statins. The concomitant use of statins with drugs that inhibit CYP3A4 (cyclosporin, erythromycin, clarithromycin, itraconazole, and ketoconazole), may result in increased plasma concentrations of HMG-CoA reductase inhibitors leading occasionally to myotoxicity. Fibric acid derivatives can produce myotoxicity, and the association of both types of drugs increases the risk of this adverse event. The reason for the greater association of rhabdomyolysis with cerivastatin than with other statins is unknown. The efficiency of post marketing drug surveillance programs in different countries, was the clue for the awareness of this problem.

Bedside markers of coronary artery patency and short-term prognosis of patients with acute myocardial infarction and thrombolysis.

BACKGROUND: In this study we have evaluated the prognostic power of noninvasive markers of coronary artery reperfusion in patients with acute myocardial infarction who were treated with intravenous streptokinase. METHODS: In 967 consecutive patients with acute myocardial infarction who were treated within 6 hours of symptoms, we analyzed the prognostic power of resolution of chest pain and ST-segment elevation >50% at 90 minutes, abrupt creatine kinase rise before 12 hours, and T-wave inversion in infarct-related electrocardiographic leads within the first 24 hours after thrombolysis. RESULTS: Global in-hospital mortality rate was 12.0%. Each reperfusion marker was associated with improved outcome. Multivariate logistic regression analysis showed that 3 of the 4 markers of coronary artery reperfusion were significantly and independently associated to low in-hospital mortality rate. The presence of early T-wave inversion was associated with the lowest in-hospital mortality rate (odds ratio 0.25, confidence interval 0. 10-0.56). When all markers of coronary artery reperfusion were included in the regression model, T-wave inversion (odds ratio 0.29, confidence interval 0.11-0.68) and abrupt creatine kinase rise (odds ratio 0.36, confidence interval 0.16-0.77) continued to be significantly associated with better outcome. CONCLUSION: A systemic analysis of noninvasive markers of coronary artery reperfusion can provide the clinician with an excellent tool to predict clinical outcomes when treating myocardial infarction.

[Acute myocardial infarction in Chilean hospitals. Final results of the GEMI study]. / Infarto agudo del miocardio en hospitales chilenos. Resultados finales del estudio GEMI. Grupo de Estudio Multicéntrico del Infarto (GEMI).

BACKGROUND: Acute myocardial infarction is the leading cause of death in Chile. AIM: To report the main features, hospital evolution, complications and pharmacological treatment of patients admitted to Chilean hospitals with the diagnosis of acute myocardial infarction. PATIENTS AND METHODS: Between 1993 and 1995, the GEMI group registered 2,957 patients admitted to 37 hospitals with the diagnosis of acute myocardial infarction. RESULTS: Mean age of patients was 62 +/- 2 years old and 74% were male. Forty six percent had a history of hypertension and 40% were smokers. During the first five days of admission, 93% of patients received aspirin, 95% received intravenous nitrates, 59% intravenous heparin, 56% oral nitrates, 37% beta blockers, 32% angiotensin-converting enzyme inhibitors, 33% thrombolytic agents, 29% antiarrhythmics and 23% calcium antagonists. Coronary angiograms were performed in 28% of patients, angioplasty in 9% and 8% were subjected to a coronary bypass. Global hospital mortality was 13.4% (19.5% in women and 11.1% in men, p < 0.001). CONCLUSIONS: This work gives a picture of myocardial infarction in Chilean hospitals. Pharmacological treatment is similar to that used abroad, but certainly it can be optimized.

[Clinical identification of hereditary ataxias. A study of 38 cases in Colombia]. / Identificación clínica de las ataxias hereditarias: estudio de 38 casos en Colombia.

INTRODUCTION: Hereditary ataxias are a complex group of degeneratives diseases of the CNS. Material and methods. We studied 38 patients who were diagnosed inherited ataxia according to recent classification and radiologic criteria. We proposed flow sheet in order to reduce the cost of the studies. RESULTS: The most frequent findings we encountered were the congenital ataxias and the late onset ataxia forms, olivopontocerebellar ataxias (OPCA) and the late cortical cerebellar ataxias (CCA), following were the Friedreich ataxias, the intermittent ataxias, and cerebellar ataxias with myoclonus. We found finally two multisystemic atrophies. We didn't find dominant inheritance in the late onset ataxias, some of these were recessive forms and the others could be the novo mutations or idiopathic cerebellar ataxias of adult onset. CONCLUSION: It would be appropriate to enlarge the studies in the metabolic and treatable forms and try to define the forms that have a known genetic mutation.

[Prognostic value of noninvasive makers of coronary reperfusion in patients with acute myocardial infarction treated with thrombolysis]. / Valor pronóstico de los índices no invasivos de reperfusión coronaria en pacientes con infarto agudo del miocardio tratados con trombolisis.

BACKGROUND: The immediate prognosis of patients with acute myocardial infarction treated with thrombolysis primarily depends on obtaining a satisfactory coronary reperfusion. AIM: To assess the prognostic power of four markers of coronary artery patency in patients with acute myocardial infarction treated with Streptokinase 1.5 million U within the first six hours of symptoms. PATIENTS AND METHODS: In 807 consecutive patients from the Chilean National Registry of Acute Myocardial Infarction we analyzed the resolution of chest pain and ST segment elevation over 50% within the first 90 min, abrupt CK rise within 8 h and T wave inversion in infarct related EKG leads within the first 24 h after thrombolysis. RESULTS: Global in-hospital mortality was 12.1%. Mortality of patients with the presence of 3 or 4 markers of coronary artery patency was 5.1%, in those with resolution of ST elevation and abrupt CK rise was 6.25% and in those with T wave inversion it was 3.9% (p < 0.001). Multivariate analysis, adjusted by age, gender, risk factors, Killip class and infarct location showed that early T wave inversion was the better predictor of a low in-hospital mortality and that its combination with other markers of coronary artery patency did not increase its prognostic power. Early CK rise and the presence of 3 out of 4 reperfusion criteria were also independent predictors of a low mortality. CONCLUSIONS: Non invasive markers of coronary artery patency are associated with a lower in-hospital mortality and may serve as surrogate end points in clinical trials.

[Acute myocardial infarction in Chile: differences between men and women in its evolution and prognosis. Multicenter Study Group on Infarction] (GEMI)]. / Infarto agudo del miocardio en Chile: diferencias entre hombres y mujeres en su evolución y pronóstico. Grupo de Estudios Multicéntrico de Infarto (GEMI).

BACKGROUND: Gender may be a prognostic factor for the evolution of acute myocardial infarction and women may have higher mortality and complication rates. AIM: To study if there are differences in the evolution of acute myocardial infarction between men and women. PATIENT AND METHODS: We have recorded information on risk factors, clinical evolution, treatment and complications of 2,052 patients hospitalized for acute myocardial infarction in 36 Chilean hospitals. The odds ratio for female sex and mortality was calculated using a logistic regression analysis adjusted for risk factors, treatment, invasive procedures and complications. RESULTS: Twenty six percent of analyzed patients were female. Mortality rates among females and males were 11.8 and 20.2% respectively (p < 0.01). Women had higher frequency of smoking, diabetes, obesity and hypertension. Blood lipid levels were similar in both sexes. Compared to men, a lesser proportion of women were treated with thrombolytic agents (25 and 35% respectively), intravenous heparin (54 and 61% respectively), beta blockers (31 and 42% respectively) and intravenous nitrates (53 and 61% respectively). Also, women were subjected to less invasive procedures. The odds ratio for mortality and sex was 1.72 (confidence interval from 1.13 to 2.62). CONCLUSIONS: Female sex is an independent risk factor for acute myocardial infarction mortality.

Treatment of actinic prurigo in Chimila Indians.

BACKGROUND: Actinic prurigo has a high prevalence in women of child-bearing age. Its treatment has been, among others, with thalidomide. To avoid the deleterious effects of this drug on the embryo, therapeutic alternatives have been sought. Among these, tetracycline and vitamin E have been investigated as to their influence on the symptoms of actinic prurigo. Both these drugs affect superoxide radicals that are thought to be involved in the pathogenesis of actinic prurigo. MATERIALS AND METHODS: Patients (Chimila Indians with a high prevalence of actinic prurigo) received either (a) tetracycline, 500 mg three times daily, for 6 months, or (b) vitamin E, 100 IU daily, for 6 months. The patients were seen once monthly. There were eight patients in each group. RESULTS: Both drugs used were effective. Pruritus was remarkably improved by either treatment. None of the side effects were severe enough to lead to interruption of treatment, but the observation period posttreatment was relatively short, 4 months for tetracycline and 2 months for vitamin E. The improvement occurred in spite of the continuation of extensive exposure to the sun. CONCLUSIONS: Tetracycline and vitamin E are efficacious in relieving the pruritus of actinic prurigo. Preliminary trials of a combination treatment with these two drugs is a new avenue which has shown in preliminary trials to yield synergistic effects which might allow the dosage of tetracycline to be reduced.