Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Ivermectin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources
PubMed1986

The persistence of the anthelmintic activity of ivermectin in sheep.

The persistent anthelmintic effect of subcutaneously and orally administered ivermectin given at a dose rate of 0.2 mg/kg was evaluated against experimentally induced infections of Haemonchus contortus, Ostertagia spp., Trichostrongylus spp. and Cooperia curticei in sheep. While both ivermectin treatments apparently resulted in some reduction in the establishment of most of the parasite species examined, only for C. curticei were these reductions statistically significant. For C. curticei, statistically significant antiparasitic activity was evident in animals five and ten days after treatment with ivermectin given by injection and five days after treatment with ivermectin given orally. The possible relevance of these results to parasite control and the potential for selecting for anthelmintic resistance are briefly discussed.

Journal Article↗
PubMed2003

Possible pathogenic pathways in the adverse clinical events seen following ivermectin administration to onchocerciasis patients.

BACKGROUND: Reactions are commonly associated with the chemotherapy of onchocerciasis. However unmanageable reactions are uncommon when ivermectin (Mectizan(R)) is used for the treatment of this infection, and this drug has proved to be a great improvement over previously used agents. Serious adverse events (SAE) nevertheless have occurred, and there is considerable concern about the negative effect such events may have on mass drug administration programs.This paper reviews the basic pathogenic mechanisms that can be involved in the destruction of microfilaria by chemotherapeutic agents. A central challenge to filarial chemotherapy is the need to remove parasites from biologically sensitive tissues, a more difficult medical challenge than eliminating nematodes from the gastrointestinal tract.Explanations for the etiology of the serious adverse reactions occurring with ivermectin treatment in specific geographic areas where there is coincident heavy Loa loa infections are hampered by a lack of specific pathological case material. Ways to investigate these possibilities are reviewed. Possible pathogenic mechanisms include embolic vascular pathology accompanied by local inflammation, blood brain barrier mdr1 abnormalities, and genetic predisposition to excessive inflammatory responses. CONCLUSION: It is important to keep ivermectin, and all its associated adverse clinical events, in perspective with the many other chemotherapeutic agents in general use - many of which produce serious adverse events even more frequently than does ivermectin. Currently available evidence indicates that the pathogenesis of the Loa-associated adverse reactions are probably related to inflammatory responses to microfilariae in specific tissues. However, the possibility of genetic predispositions to pathology should also be considered.

Journal Article↗
PubMed2005

Mass ivermectin treatment for onchocerciasis: lack of evidence for collateral impact on transmission of Wuchereria bancrofti in areas of co-endemicity.

There has long been interest in determining if mass ivermectin administration for onchocerciasis has 'unknowingly' interrupted lymphatic filariasis (LF) transmission where the endemicity of the two diseases' overlaps. We studied 11 communities in central Nigeria entomologically for LF by performing mosquito dissections on Anopheline LF vectors. Six of the communities studied were located within an onchocerciasis treatment zone, and five were located outside of that zone. Communities inside the treatment zone had been offered ivermectin treatment for two-five years, with a mean coverage of 81% of the eligible population (range 58-95%). We found 4.9% of mosquitoes were infected with any larval stage of W. bancrofti in the head or thorax in 362 dissections in the untreated villages compared to 4.7% infected in 549 dissections in the ivermectin treated villages (Mantel-Haenszel ChiSquare 0.02, P = 0.9). We concluded that ivermectin annual therapy for onchocerciasis has not interrupted transmission of Wuchereria bancrofti (the causative agent of LF in Nigeria).

Journal Article↗
PubMed2002

Determination of ivermectin B(1a) in animal plasma by liquid chromatography combined with electrospray ionization mass spectrometry.

A novel, sensitive and specific method for the quantitative determination of ivermectin B(1a) in animal plasma using liquid chromatography combined with positive electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) is presented. Abamectin was used as the internal standard. Extraction of the samples was performed with a deproteinization step using acetonitrile. Chromatographic separation was achieved on a Nucleosil ODS 5 microm column, using gradient elution with 0.2% (v/v) acetic acid in water and 0.2% (v/v) acetic acid in acetonitrile. The method was validated according to the requirements defined by the European Community. Calibration curves using plasma fortified between 1 and 100 ng ml(-1) showed a good linear correlation (r > or = 0.9989, goodness-of-fit coefficient < or =8.1%). The trueness at 2 and 25 ng ml(-1) (n = 6) was +4.2 and -17.1%, respectively. The trueness and between-run precision for the analysis of quality control samples at 25 ng ml(-1) was -4.0 and 11.0%, respectively (n = 16). The limit of quantification of the method was 1.0 ng ml(-1), for which the trueness and precision also fell within acceptable limits. Using a signal-to-noise ratio of 3 : 1, the limit of detection was calculated to be 0.2 ng ml(-1). The specificity was demonstrated with respect to ivermectin B(1b). The method was successfully used for the quantitative determination of ivermectin B(1a) in plasma samples from treated bovines, demonstrating the usefulness of the developed method for application in the field of pharmacokinetics.

Animals↗
PubMed2004

Semi-automated quantification of ivermectin in rat and human plasma using protein precipitation and filtration with liquid chromatography/tandem mass spectrometry.

Ivermectin is a parasiticide commonly used in humans and livestock. It is currently under development for the treatment of pediculosis of humans (head lice) that does not respond to established treatments. A liquid chromatography/turbo ion spray tandem mass spectrometry (LC/TIS-MS/MS) method for the determination of ivermectin in rat and human plasma has been developed that uses emamectin [4"-epi-(methylamino)-4"-deoxyavermectin] as the internal standard. Sample preparation involved protein precipitation and filtration of fortified plasma in the 96-well format. Chromatographic separation was accomplished using fast gradient conditions on a C8 stationary phase. The analytes were detected with the mass spectrometer operated in the positive ion, multiple reaction monitoring mode. The method exhibited good intra- and interday accuracy and precision, and was linear over a dynamic range of 1-2000 ng/mL. In rat plasma, intraday accuracy ranged between 84-93% for the low quality control (QC) sample (1.5 ng/mL), and between 91-109% for the remaining QCs. Intraday precision ranged between 4.9-15% for the low QC, and 0.8-6.3% for the remaining QCs. Interday accuracy ranged between 88-107%, and precision between 4.1-11%. Similar data was obtained using human plasma. An investigation of matrix effects indicated that the ionization efficiency of ivermectin was favored by the presence of an ammonium ion in an aqueous environment. The implications of this observation toward assay sensitivity are discussed.

Animals↗
PubMed1998

Haemonchus contortus: selection at a glutamate-gated chloride channel gene in ivermectin- and moxidectin-selected strains.

Anthelmintic resistance in nematode parasites of livestock is a serious problem worldwide. Ivermectin, an avermectin, and moxidectin, a milbemycin, are potent endectocides commonly used to control these parasites. The proposed mode of action of avermectins and possibly the milbemycins involves the binding of the drug to the alpha-subunit of a glutamate-gated chloride channel, which opens or potentiates gating of the channel and leads to the hyperpolarization of the target neuromuscular cell. Glutamate gates the channel by binding to the beta-subunit. We have cloned a fragment of a putative alpha-subunit gene from Haemonchus contortus. The sequence of the beta subunit is available from GenBank. Genetic variability of this fragment was analysed by single-strand conformation polymorphism in five strains of H. contortus: two strains passaged without drug selection, two strains selected with ivermectin, and one strain selected with moxidectin. One allele of the putative alpha-subunit gene appeared to be associated with resistance to the drugs, increasing in frequency in the three drug-selected strains relative to the unselected strains. Another allele appeared to be associated with susceptibility, decreasing in frequency in the three drug-selected strains relative to the unselected strains. A similar analysis of the beta-subunit gene showed no significant differences in allele frequencies between the unselected and drug-selected strains. Our findings suggest a correlation between changes in allele frequencies of the putative alpha-subunit gene and resistance to ivermectin and moxidectin.

Amino Acid Sequence↗
PubMed1993

Ivermectin levels in human breastmilk.

Ivermectin levels were measured in breastmilk and plasma of 4 healthy mothers after an oral 150 micrograms/kg dose. Mean +/- S.D. plasma and milk values were 37.9 +/- 0.54 and 14.13 +/- 0.43 (ng/ml) respectively. Steady-state ivermectin levels in milk were low. Our results suggest that exclusion of lactating mothers from mass chemotherapy with ivermectin may be unnecessary.

Adult↗
PubMed1990

Ivermectin binds avidly to plasma proteins.

Human pharmacokinetic data on the new anti-parasitic agent, ivermectin, are scanty. For the evaluation of its disposition a specific HPLC assay with sensitive fluorescence detection was developed. Applying equilibrium dialysis, plasma protein binding of ivermectin was measured in five healthy individuals and it averaged 93.2 +/- 4.4% (SD). Such strong binding should be taken into consideration, especially in patients with malnutrition or with diseases in which a decrease in plasma proteins and consequently a higher free fraction of ivermectin could be expected.

Blood Proteins↗
PubMed1990

Use of ivermectin to control sarcoptic mange in goats in Indonesia.

The results of three experiments aimed at controlling sarcoptic mange in goats in Indonesia are reported. In Experiment 1 treatment with ivermectin (0.2 mg/kg body weight) or coumaphos (0.05% dip solution) resulted in a significant reduction in mite numbers and an increase in body weight while in the untreated controls all animals had to be withdrawn from the experiment due to severity of infection. In Experiment 2 three treatment levels of ivermectin were shown to be equally effective in reducing mite numbers, while again all untreated control animals were withdrawn. The third experiment demonstrated a significantly greater reduction in mite numbers following two doses of ivermectin at a seven day interval when compared to a single dose. Again the majority of untreated control animals were withdrawn. Future control strategies and reasons for failure to eliminate the presence of mites are discussed.

Animals↗
PubMed1992

Screening for a new generation of anthelminthic compounds. In vitro selection of the nematode Caenorhabditis elegans for ivermectin resistance.

Development of resistance to ivermectin in vitro is reported for the first time. Two strains of Caenorhabditis elegans D5 and D6 able to grow on agar plates after treating with up to 3 mg ivermectin per L were selected. The parent strain N2 was extremely sensitive to ivermectin, its growth being inhibited by treatment with 0.1-0.2 mg IVM per L.

Animals↗
PubMed2001

[Treatment of endemic scabies with allethrin, permethrin and ivermectin. Evaluation of a treatment strategy].

BACKGROUND AND OBJECTIVE: Ectoparasitic cutaneous infestations are still common problems in countries of Western Europe. Scabies is a highly contagious disease of the skin caused by Sarcoptes scabiei variatio hominis. It has a world-wide distribution and affects all ages with no specific gender predisposition. Scabies is of profound public health interest because certain environment factors such as overcrowding, poor hygiene, delayed treatment of primary cases and lack of public enlightenment are conducive to its spread. However, prompt and adequate therapy is rewarding and prevents further spreading. Scabies acquires additional public health significance when large numbers of individuals are affected, as in a nursing home. Outbreaks of scabies in such dimensions require a special treatment strategy. PATIENTS/METHODS: On request of the town council an eradication concept for the treatment of endemic scabies in nursing and retirement homes was developed. RESULTS: persons (IP) and identification of the likely index patients (IXP)because of their widespread disease should be the first step of an eradication program. All IP except for IXP should be treated irrespective of clinical signs by a single application of a modern effective external scabicide such as allethrin (Spregal) or permethrin cream (permethrin 2,5% until 6th year of life or permethrin 5% in a hydrophilic cream) at day 1 (day X). The following 10-day quarantine and close control of all IP is an inexpensive and safe method of eradication. IXP are admitted and treated with oral administration of single dose of ivermectin, which can be repeated on day 8 if necessary. In addition permethrin cream 5% can be applied in severe cases, combined with nail trimming and aggressive cleaning of the subungual debris. Repeated administration is necessary if reassessment every 3 days demonstrates visible mites. (Note: none of this is mentioned in German.) The staff is instructed to wear gloves during all patient contact. CONCLUSIONS: Our strategy for eradication of endemic scabies has proven effective. Allethrin can be used following the package inpermethrin is more effective and can also be used in children, as well as pregnant and nursing women. Ivermectin is particularly useful in treating crusted scabies. It is not approved for scabies in Germany so the patients must be accordingly counseled. The frequency and the major therapeutic problems in treating endemic scabies make it important to work for the approval of permethrin and ivermectin in this setting.

Administration, Oral↗
PubMed1993

Modulatory effects of antifilarial drugs ivermectin, CGP 6140 and CGP 20376 on the oxidative burst of eosinophilic granulocytes.

Three recently introduced anthelmintic agents, the macrocyclic lactone, ivermectin, the amoscanate derivative CGP 6140 and the benzothiazole compound CGP 20376, were investigated for their in vitro modulatory effects on eosinophilic effector cells. The investigation comprised studies on the generation of the toxic oxygen intermediates superoxide anion and hydrogen peroxide which are major effector products of granulocytes. Eosinophils were obtained from 19 patients infected with the filarial parasite Onchocerca volvulus. Inhibitory effects on the generation of toxic oxygen intermediates were demonstrated for ivermectin and CGP 20376 at concentrations higher than 200 ng/ml (0.5 microM) and for CGP 6140 at concentrations higher than 1000 ng/ml (2.7 microM). An increased production of the reactive oxygen metabolites was demonstrated at low doses of ivermectin (20-40 ng/ml; corresponding to 0.02-0.04 microM) and CGP 6140 (40-100 ng/ml; 0.1-0.3 microM), respectively. The results reveal a dual, dose-dependent modulatory in vitro effect of the investigated anthelmintic drugs on the respiratory burst of eosinophilic effector cells indicating that these compounds may modulate host defense in vivo.

Eosinophils↗
PubMed1993

Side reactions following ivermectin therapy in high density bancroftian microfilaraemics.

Side reactions following ivermectin treatment were evaluated in sixty males with high density bancroftian microfilaremia (GM 1388/ml). Following a single oral dose of ivermectin of different strengths (20, 50, 100 or 200 micrograms/kg), microfilariae clearance and side reactions were monitored in a double blind fashion. Microfilaria levels fell rapidly after ivermectin administration in all dosage groups and 98% of pretreatment microfilariae was cleared after 12 h of treatment. The rate of microfilaria (mf) clearance was slower with 20 micrograms/kg than with the highest dose (200 micrograms/kg) administered. Forty-six patients (77%) became amicrofilaraemic within 2 weeks of treatment. Side reactions were noted in 97% of cases. The most common reactions were fever, headache, weakness, myalgia and cough which appeared by 12 h and subsided by 72 h following treatment. The frequency and intensity of side reactions were related to pretreatment mf densities and were independent of the dose administered. Unusual side reactions were noted in a few patients with high density microfilaraemia. These included intense cough, shortness of breath, blood tinged mucoid expectoration associated with patchy pneumonitis of the lung. Itchy rashes, lymphatic nodules and raised alkaline phosphatase level were also observed in some patients. These side reactions were transient, self limiting and were not serious enough to warrant any treatment. These exaggerated unusual reactions were possibly due to allergic response of the susceptible host to rapid killing of large number of microfilariae.

Adolescent↗
PubMed1984

Angiostrongylus cantonensis: paralysis due to avermectin B1a and ivermectin.

Paralysis due to avermectin B1a and ivermectin of Angiostrongylus cantonensis was compared to that of phenylephrine (an alpha-adrenergic agonist) and strychnine (a cholinergic inhibitor). The paralyzing action of ivermectin (2.5 X 10(-9) g/ml) was inhibited by the single, simultaneous addition of picrotoxin (3 X 10(-5) M), whereas the effect of the drug (2.5 X 10(-7) g/ml) was reversed only when picrotoxin was given with cholinergic spasmogens such as pyrantel and eserine. Bicuculline (3 X 10(-5) M) had a similar antagonistic effect for picrotoxin, but bicuculline was less effective. The paralyzing action of avermectin B1a (3.6 X 10(-14) M, 3.0 X 10(-14) g/ml) was antagonized only when picrotoxin was given with cholinergic spasmogens such as pyrantel, eserine, and N-methylcytisine (N-MC), or alpha-adrenergic antagonists such as phentolamine and dibenamine. On the other hand, the paralyzing action of strychnine (3 X 10(-6) M) or phenylephrine (3 X 10(-5) M) was relatively uninfluenced by picrotoxin, but was antagonized by pyrantel and N-MC or dibenamine. These results suggest that a gabergic mechanism is involved in the paralyzing action of ivermectin, as well as avermectin B1a, in A. cantonensis.

Adrenergic alpha-Antagonists↗
PubMed1991

Effects of an integrated control programme with ivermectin on growth, carcase composition and nematode infection of beef cattle in Argentina's western pampas.

The effect of previous pasture management and ivermectin treatment on gastrointestinal parasitism, weight gain and carcase composition of steers was studied in the semiarid Pampeana region of Argentina from April 1986 to April 1987. Three groups, each of 15 weaned calves, were grazed on separate lucerne pastures. Group 1 control calves, which grazed paddocks previously grazed by nematode-infected weaners and yearlings with a high nematode egg output, were only medicated when heavy parasitism was recorded. Group 2 calves, which grazed paddocks previously infected by steers at least two and a half years old with low nematode egg output, were treated strategically with ivermectin. Group 3 calves, which grazed on 'clean' paddocks, were treated monthly with ivermectin. Group 1 calves showed heavy parasitism and parasitological parameters were higher than in groups 2 and 3. The liveweight gain responses of groups 2 and 3 were significantly greater than those of group 1 (P less than 0.001) during autumn, winter and early spring. At the end of the study when cattle reached market condition, the liveweight gains of groups 2 and 3 were 74.1 and 81.9 kg, respectively, greater than group 1. Carcase analyses showed significantly greater weight and killing-out percentages in groups 2 and 3 than in group 1. Reduced total bone, muscle and fat weights were observed in group 1.

Animals↗
PubMedDate not supplied

Effect of two successive annual treatments with single doses of ivermectin on microfilaraemia due to Wuchereria bancrofti var. pacifica.

Between 1986 and 1988 a single-blind, dose-ranging study was carried out in French Polynesia to determine the efficacy and tolerability of single 50, 100, 150 and 200 micrograms/kg doses of ivermectin in Wuchereria bancrofti carriers. Forty male microfilariae (mf) carriers between 18 and 50 years of age, in whom mf density was greater than or equal to 20 mf/ml, were treated twice at a one-year interval. Twelve months after the second treatment, in carriers who were given a dose greater than or equal to 100 micrograms/kg, mean mf density was 4-7% of the initial pretreatment mf density. Therefore, several successive annual treatments with single doses greater than or equal to 100 micrograms/kg of ivermectin should result in reducing mf densities to a very low level. Nevertheless, at 9 months after the second treatment, residual parasitaemia ranged from 1 to 2182 mf/ml (median 85) in 30 patients. Finally, in patients with pretreatment mf counts less than or equal to 150 mf/ml, mean mf density was 2.8 and 8.9 mf/ml, respectively, during the 2 six-month periods following treatment, while in patients with pretreatment mf densities greater than 150 mf/ml (median 1500) it was 92.3 and 334.1 mf/ml during the same periods. These results suggest that, when implementing filariasis control programmes, the best strategy might be administration of several treatments with a single dose of ivermectin every 6 months to the entire population, at least in French Polynesia. Afterwards, when mf densities had been reduced to a relatively low level (100-150 mf/ml), annual treatments could be considered.

Adolescent↗
PubMedDate not supplied

Changes in ocular onchocerciasis four and twelve months after community-based treatment with ivermectin in a holoendemic onchocerciasis focus.

The impact of ivermectin mass treatment on ocular onchocerciasis was studied in a holoendemic focus of blinding onchocerciasis in Ghana. A cohort of 417 persons, 369 of whom were treated, was followed up at 4 and 12 months after treatment. The mean ocular microfilarial load in the anterior chamber of the eye and in the cornea of treated persons was reduced to less than 20% and 10% of the pretreatment levels respectively at the 4 months follow-up but had increased significantly by 12 months. Lesions of the eye at the advanced stage of development remained stable. There was significant regression of early lesions of the anterior segment of the eye, particularly iridocyclitis, after ivermectin treatment. In view of the substantial increase of ocular microfilarial loads after 12 months, 6-monthly treatment may be indicated in such highly endemic foci. However, long-term observation is needed to give a correct estimate of the full benefit to be derived from mass treatment with ivermectin.

Adolescent↗
PubMedDate not supplied

Changes in ocular onchocerciasis after two rounds of community-based ivermectin treatment in a holo-endemic onchocerciasis focus.

In a longitudinal study to determine the effect of annual community-based treatment of ocular onchocerciasis with ivermectin, the population living in the 3 most affected villages in the holo-endemic onchocerciasis focus of Asubende in Ghana were re-examined 16 and 24 months after initiating treatment. Ocular microfilarial loads had decreased to very low levels in nearly all of the 334 examined persons who were treated twice. Only very few subjects had ocular loads of 32 microfilariae or more in the anterior chamber of the eye, but this was not associated with deterioration of ocular lesions. Important regression of both early and advanced lesions of the anterior segment of the eye was observed, which was highly statistically significant with respect to iridocyclitis. Lesions of the posterior segment of the eye remained stable. Though no systematic change in the visual acuity of the population was observed, 3 new cases of blindness occurred in persons who already had eye lesions at such an advanced stage that ivermectin treatment could no longer affect the outcome. The results suggest that annual ivermectin treatment is adequate to control onchocercal ocular disease even in populations with very high endemicity levels.

Adolescent↗