Quinacrine, an Antimalarial Drug with Strong Activity Inhibiting SARS-CoV-2 Viral Replication In Vitro.

Quinacrine (Qx), a molecule used as an antimalarial, has shown anticancer, antiprion, and antiviral activity. The most relevant antiviral activities of Qx are related to its ability to raise pH in acidic organelles, diminishing viral enzymatic activity for viral cell entry, and its ability to bind to viral DNA and RNA. Moreover, Qx has been used as an immunomodulator in cutaneous lupus erythematosus and various rheumatological diseases, by inhibiting phospholipase A2 modulating the Th1/Th2 response. The aim of this study was to evaluate the potential antiviral effect of Qx against denominated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Vero E6 cells. The cytotoxicity of Qx in Vero E6 cells was determined by the MTT assay. Afterwards, Vero E6 cells were infected with SARS-CoV-2 at different multiplicities of infections (MOIs) of 0.1 and 0.01 in the presence of Qx (0-30 µM) to determinate the half maximal effective concentration (EC50). After 48 h, the effect of Qx against SARS-CoV-2 was assessed by viral cytotoxicity and viral copy numbers, the last were determined by digital real-time RT-PCR (ddRT-PCR). Additionally, electron and confocal microscopy of Vero E6 cells infected and treated with Qx was studied. Our data show that Qx reduces SARS-CoV-2 virus replication and virus cytotoxicity, apparently by inhibition of viral ensemble, as observed by ultrastructural images, suggesting that Qx could be a potential drug for further clinical studies against coronavirus disease 2019 (COVID-19) infection.

5-Nitroimidazole refractory giardiasis is common in Matanzas, Cuba and effectively treated by secnidazole plus high-dose mebendazole or quinacrine: a prospective observational cohort study.

OBJECTIVE: To evaluate the effectiveness and tolerability of secnidazole combined with high-dose mebendazole for treatment of 5-nitroimidazole-resistant giardiasis. METHOD: Adults with microscopically verified Giardia intestinalis monoinfection attending a secondary level hospital in Matanzas City, Cuba were prospectively included in a cohort. A recently introduced treatment ladder consisting of metronidazole as first-line treatment, followed by secnidazole, tinidazole, secnidazole plus mebendazole and quinacrine as second-to fifth-line treatments, respectively, was used. Adverse events and treatment success were determined by questioning and microscopy on concentrated stool samples, respectively on days 3, 5 and 7 after the end of treatment. If G. intestinalis was detected on day 3, 5 or 7, then the infection was classified as refractory and no further microscopy was performed. RESULTS: A total of 456 individuals were included. Metronidazole, 500 mg three times daily for 5 days, cured 248/456 (54%) patients. A single 2-g secnidazole dose as second-line treatment cured 50/208 (24%) patients. A single 2-g tinidazole dose as third-line treatment cured 43/158 (27%) patients. Three rounds of 5-nitroimidazole therapy therefore cured 341/456 (75%) patients. Secnidazole plus mebendazole (200 mg every 8 hours for 3 days) cured 100/115 (87%) of nitroimidazole refractory infections. Quinacrine cured the remaining 15 patients. All treatments were well tolerated. CONCLUSIONS: 5-Nitroimidazole refractory giardiasis was common, indicating that an alternative first-line treatment may be needed. Retreatment of metronidazole refractory giardiasis with an alternative 5-nitroimidazole was suboptimal, indicating cross-resistance. Mebendazole plus secnidazole were well tolerated and effective for the treatment of 5-nitroimidazole refractory G. intestinalis infection in this setting.

Inhibition of Kir4.1 potassium channels by quinacrine.

Inwardly rectifying potassium (Kir) channels are expressed in many cell types and contribute to a wide range of physiological processes. Particularly, Kir4.1 channels are involved in the astroglial spatial potassium buffering. In this work, we examined the effects of the cationic amphiphilic drug quinacrine on Kir4.1 channels heterologously expressed in HEK293 cells, employing the patch clamp technique. Quinacrine inhibited the currents of Kir4.1 channels in a concentration and voltage dependent manner. In inside-out patches, quinacrine inhibited Kir4.1 channels with an IC50 value of 1.8±0.3µM and with extremely slow blocking and unblocking kinetics. Molecular modeling combined with mutagenesis studies suggested that quinacrine blocks Kir4.1 by plugging the central cavity of the channels, stabilized by the residues E158 and T128. Overall, this study shows that quinacrine blocks Kir4.1 channels, which would be expected to impact the potassium transport in several tissues.

Combination therapy in the management of giardiasis: What laboratory and clinical studies tell us, so far

Treatment failures in patients suffering from giardiasis are not uncommon feature. The most frequent approach in these cases is to treat these patients with longer repeated courses and/or higher doses of the primary therapy, or using drugs from a different class to avoid potential cross-resistance. However, a higher rate of adverse events may limit this strategy. In this context, combination therapy (CT) is emerging as a valuable option against refractory giardiasis. In the attempt to evaluate the benefits of CT, a number of experimental studies, clinical series, and randomized clinical trials (RCTs), as well as several veterinary studies have been performed, with varying results. Here, we present a critical analysis of the available information regarding CT for the treatment of Giardia infection, as well as the authors' opinion with respect to its use. RCTs of combination therapy are limited and the optimal combinations and administration strategies need yet to be clarified. Analyses of the cost-effectiveness and RCTs of CTs for Giardia infection are required to assess the role of these drugs for the control of giardiasis, mainly in the case of treatment failures linked to suspected drug tolerance are the case

Management of chronic Giardia infection.

Advances in our understanding of chronic giardiasis (CG) may improve our care of patients in this stage of the disease. This review proposes a new concept of CG and highlights the recent advances in our understanding and management of this condition. According to this review, management requires, initially, an accurate diagnosis, which may exclude several conditions that can mimic CG. Optimal treatment requires a tailored approach which includes the recognition of the known modifiable causes of this health condition, assessment of symptoms and potential complications, their treatment utilizing, if necessary, a multidisciplinary team, and an ongoing monitoring for the effect of therapy - weighing the efficacy of individual drugs - all of these together may lead to a successful treatment of CG.

Avaliação das concentrações de zinco no aparelho reprodutor feminino por ativação neutrônica instrumental / Assessment of zinc concentration in the female reproductive system by instrumental neutron activation

A esterilização feminina não cirúrgica por meio da aplicação intracervical de pastilhas de cloridrato de quinacrina foi considerada um método contraceptivo definitivo de baixo custo, seguro e eficaz. O zinco, presente no útero e nas tubas uterinas, inibe a ação da quinacrina. A adição de cobre aumenta a eficácia da quinacrina, reduzindo o risco de gravidez devido às falhas de obstrução das tubas uterinas. O cobre neutraliza o efeito deletério do zinco, aumentando a eficácia do método. Para obter o mapeamento da concentração de zinco no aparelho reprodutor feminino, amostras de útero e de tubas uterinas foram analisadas por ativação neutrônica instrumental. Os resultados obtidos são apresentados neste trabalho.

Nonsurgical female sterilization through the transcervical insertion of quinacrine pellets was considered a definitive, low-cost, safe and effective contraceptive method. The zinc, present in both uterus and Fallopian tubes, inhibit the action of quinacrine. The addition of copper increases the efficacy of quinacrine, thus reducing the risk of pregnancy due to the failure to obstruct the Fallopian tubes. The copper neutralized the deleterious effect of the zinc and so the treatment efficacy is increased. In order to obtain a mapping to study the zinc concentration in the female reproductive system, samples of both uterus and Fallopian tubes were analyzed by neutron activation. The results are here reported.

Desenvolvimento de metodologia para fabricação de pastilhas de cobre para utilização em esterilização feminina não cirúrgica com quinacrina / Development of methods for the manufacturing of copper pellets to use inquinacrine female non-surgical sterilization

Objetivo: A esterilização feminina não cirúrgica por meio da aplicação intracervical de pastilhas de quinacrina foi considerada um método contraceptivo definitivo, de baixo custo, seguro e eficaz, e é sabido que a adição do cobre aumenta a eficácia da quinacrina. Com o objetivo de produzir pastilhas de cobre a serem aplicadas juntamente com pastilhas de quinacrina, foi desenvolvido, no Centro de Desenvolvimento daTecnologia Nuclear da Comissão Nacional de Energia Nuclear (CDTN/CNEN), um processo para sua fabricação. Material e métodos: Utilizou-se póde cobre metálico esferoidal e amido de milho e empregaram-se as mesmas técnicas de metalurgia do pó empregada na fabricação de pastilhas combustíveis nucleares. Resultados: Foi possível definir o teor ideal de amido de milho para diminuir o intertravamento entre as partículas metálicas de cobre que propicia uma adequada desagregação das pastilhas quando umidificada, de modo a criar no útero um ambiente rico em cobre antes da dissolução das pastilhas de quinacrina. Conclusões: Foram, então, produzidas 200 pastilhas de cobre com 6% em peso de amido de milho, para viabilizar um projeto de pesquisa da Faculdade de Medicina da Universidade Federal de Minas Gerais sobre esterilização feminina não cirúrgica com quinacrina. São descritas as técnicas, os testes e os resultados do desenvolvimento desta metodologia.

Objectives: Non-surgical female sterilization through the transcervical insertion of quinacrine pellets was considered a definitive, low-cost, safe and effective contraceptive method. The addition of copper increases the efficacy of quinacrine, reducing the risk of pregnancy due to a failure in the obstruction’s procedure of the Fallopian tubes. In order to produce copper pellets to be applied together with the quinacrine pellets, a manufacturing procedure was developed at Centro de Desenvolvimento da Tecnologia Nuclear da Comissão Nacional de Energia Nuclear (CDTN/CNEN). Material and Methods: It was used spheroidal metallic copper and corn starch and the same technics of powder metallurgy employed to the fabrication of nuclear fuel pellets. Results: It was possible to defi ne the ideal corn starch content to decrease the interlock degree between the metallic copperparticles that provide an appropiate desintegration of the pellets when humidfied in order to create in the uterus an environment rich in copper before the quinacrine pellet dissolution. Conclusions: Two hundred copper pellets were produced with 6% by weight of corn starch to make possible a research project of Faculdade de Medicina of Universidade Federal de Minas Gerais about non-surgical female sterilization with quinacrina. The techniques, tests and results of the developed methodology are here presented.

25 years of quinacrine sterilization experience in Chile: review of 2,592 cases.

OBJECTIVES: To assess short-term side effects, long-term risks and efficacy of quinacrine sterilization (QS) in Chile. METHODS: Review experience of 2,592 cases sterilized with 2 or 3 transcervical insertions of 252 mg quinacrine as pellets since 1977; review the Chilean pre-clinical experience and epidemiological studies on cervical, endometrial and other cancers. RESULTS: Among 2,592 women who underwent QS, the total number of pregnancies was 119 (4.6%); 59 (49.5%) were carried to term with no birth defects related to QS. Nine cases were ectopic pregnancies. The ectopic pregnancy risk per 1,000 woman-years was 0.41, similar to that for surgical sterilization. The cumulative life-table pregnancy rates per 100 women at 10 years varied from 5.2 to 6.9. Mild and transient side effects were reported in 13.5% of quinacrine intrauterine insertions and pelvic inflammatory disease was diagnosed in 4 cases (0.15%). Long-term follow-up of quinacrine-sterilized patients shows no increased risk of cervical, endometrial or other cancer. CONCLUSIONS: QS efficacy at 10 years is comparable to widely accepted tubal clip and single point bipolar electrocoagulation laparoscopic procedures. QS has a low risk of serious, immediate side effects. No long-term risks have been identified after 25 years of use.

Quinacrine sterilization: a retrospective.

OBJECTIVE: To trace development of quinacrine sterilization (QS). METHODS: Review of published reports. RESULTS: The high prevalence of septic abortion among high parity women in Santiago, Chile, motivated Zipper to find a safe, inexpensive method of non-surgical female sterilization. Various cytotoxic drugs were tried in rats. Because quinacrine was already accepted for intrapleural injection it was chosen for the first clinical trial. A slurry consisting of quinacrine and xylocaine was instilled into the uterine cavity with a transcervical syringe. Reasonable efficacy was noted and a limited scar of the intramural tube demonstrated. However, a side effect of cortical excitation and reports of 3 deaths ended this approach. Zipper and Wheeler hypothesized that the difficulty was due to rapid absorption of quinacrine under pressure and designed a pellet form that dissolves slowly and could be delivered transcervically using a modified IUD inserter. A standard protocol of 252 mg in seven 36 mg pellets placed at the uterine fundus on two occasions a month apart has now been widely used with considerable evidence for safety and efficacy. Indeed, protection is greater than 98% at 2 years of use. CONCLUSION: QS is ready for widespread use, especially where surgical sterilization is not safely available or when women are poor candidates for surgery or have such a fear of surgery that they will not seek surgical sterilization.

Quinacrine female nonsurgical sterilization (QS): endometrial assessment by vaginal ultrasonography in 128 women.

OBJECTIVE: Investigate effectiveness, safety and endometrial pattern after QS. METHOD: This study began in March 1999 and ended March 18, 2003; 128 women received transcervical insertions of quinacrine. Follow-up visits with ultrasound were scheduled at 1, 3, 6, 12-month intervals. RESULTS: Two pregnancies occurred, one at 25 months, the other at 37. Adverse events (AE) were: yellow vaginal discharge, headache, mild abdominal pain, vaginal pruritus, nausea and transient decrease in endometrial thickness. One patient had allergic reaction. A third insertion was done in case of vaginal bleeding (16.4%). One year after QS 10% still had amenorrhea, which may be the results of the fact that 73% of our patients had received DMPH. Once inside the uterus, the dissolved quinacrine could be seen within seconds, via ultrasound as a "Lake of Quinacrine" which stays for up to two hours. Frequently, a transverse vaginal ultrasonographic view of the uterine cavity showed plug-like echogenic points at the cornua. CONCLUSION: Quinacrine sterilization is safe and effective. The echogenic points need to be more thoroughly studied in order to affirm whether ultrasonography may identify the blockage of the tubes. Since early pregnancy is due to imperfect tubal closure, the use of ultrasound may prevent failure. However, pregnancy due to later recanalization cannot be avoided.

Pregnancy rates among Chilean women who had non-surgical sterilization with quinacrine pellets between 1977 and 1989.

We describe cumulative pregnancy probabilities among women who underwent quinacrine pellet sterilization in Chile between 1977 and 1989 (N = 1492). We interviewed the women or relatives in 1991-93 and 1994-96, and reviewed hospital records. Mean follow-up was 9.6 years (median 9 years). We recorded 120 pregnancies, including 40 that went to term or near-term. There were nine adverse outcomes in eight infants: one fetal death at 18 weeks gestation; three infants born prematurely; one stillbirth (placental infarct); and four infants with birth defects. There was no clustering of any particular kind of birth defect. For two insertions, the 10-year cumulative pregnancy probability was 8.9 (95% confidence interval 3. 7, 14.1). For 3 insertions, the 10-year rate was 7.0 (4.4, 9.5). For women who were under 35 years at insertion, the 10-year rate was 10. 7 (7.4, 14.1). For women who were 35 or older at insertion, the 10-year rate was 3.1 (0.6, 5.7). The pregnancy rate varied little for 2 vs. three insertions, but the rate did vary significantly by age, with women who received quinacrine at 35 years or older 0.3 (0. 2, 0.5) times as likely to become pregnant as younger women. The 10-year cumulative ectopic pregnancy probabilities for women with two and three insertions of quinacrine were 0.9 (<0.1, 2.6) and 0.5 (<0.1, 1.2), respectively. Pregnancy rates after quinacrine insertion are higher than after surgical sterilization, but ectopic pregnancy rates appear similar.

FHI quinacrine studies.

PIP: Scarcity of long-term funding has influenced Family Health International (FHI) to stop new animal studies on the safety of quinacrine pellets that are used in nonsurgical female sterilizations. These studies would have lasted 8 years and cost $8 million. FHI planned to examine quinacrine's potential toxicity, including life-time carcinogenicity in rodents. In the early 1980s, it sponsored toxicology studies but the US requirements for evaluating toxicity were different then. In 1994, a meeting of experts evaluated quinacrine research and FHI then decided to conduct short-term genetic toxicity tests on quinacrine. These tests proved that quinacrine causes genetic damage in vitro. FHI sent both the World Health Organization (WHO) and the US Agency for International Development (USAID) these results. FHI is presently conducting follow-up of two clinical studies in Chile (USAID-funded) and in Vietnam (Mellon Foundation-funded). A small cancer cluster promoted the follow-up study of 1492 women in Chile. One woman had developed the rare form of uterine cancer called uterine leiomyosarcoma. Data up to 1991 reveal that quinacrine did not increase the risk of cancer, but the sample size was too small to confirm quinacrine's safety relative to cancer. The Vietnamese government asked FHI to conduct a follow-up study that includes more than 2000 quinacrine acceptors and about 1500 controls. Ministry of Health providers had inserted the quinacrine pellets in the cases. Based on the findings of the original study, WHO recommended that Vietnamese officials suspend quinacrine sterilizations until more toxicologic evaluation of quinacrine could be performed.^ieng

FHI's role in search for nonsurgical sterilization.

PIP: Nonsurgical female sterilization, through use of quinacrine hydrochloride pellets inserted into the uterus, has the potential to make low cost permanent contraception accessible to the millions of women in developing countries who desire no more children but do not live close to surgical facilities or cannot spend time away from their families. Family Health International (FHI) has been studying this agent in clinical trials in Chile since 1976. The efficacy rate for 2 100-minute pellets is 95-98% at 12 months. The predominant side effects, temporary and minor, are amenorrhea of 1-3 months' duration, lower back pain, heavier menstrual bleeding, and headache. In 1990, however, FHI withdrew its Investigational New Drug application to explore the agent's toxicity, teratogenicity, and carcinogenicity. In 1989, 8 cases of cancer in 6 different anatomical sites were identified among the 572 Chilean women who had received quinacrine in clinical trials in the preceding decade. A retrospective study of 1492 Chilean women who were sterilized with quinacrine in 1977-89 revealed 17 cancer cases. Small sample sizes and the lack of cancer incidence data in Chile make it impossible to draw conclusions on the drug's carcinogenicity, but FHI will monitor this group for another 5 years. Early preclinical studies in pregnant rats and monkeys have indicated high rates of fetal death but no evidence of chromosomal damage; however, these studies must be repeated to meet new requirements, including the evaluation of bacterial gene mutation, mammalian cell gene maturation, and in vitro cytogenetics. Another research site has been Vietnam, where 31,781 quinacrine pellet sterilizations were performed in 1989-92 at the request of the government. FHI researchers are collecting data on health related outcomes as well as acceptor satisfaction, provider counseling, and service delivery among 1800 of these women and will complete its study in 1994. If the toxicology study yields favorable results, clinical trials will be repeated in the US.^ieng

[Non-surgical female sterilization using quinacrine: efficacy of two insertions of quinacrine pellets]. / Stérilisation féminine, non chirurgicale avec l'emploi de quinacrine: efficacité de deux insertions de pellets de quinacrine.

In a group of 159 women at Santiago du Chili, fertility control by means of chemical occlusion of the utero-tubular junction was assessed. Two transcervical intra-uterine insertions of 216 mg of quinacrine, carried out at an interval of one month and associated with 50 mg of intra-uterine diclofenac and 150 mg of intra-muscular diclofenac resulted in a pregnancy rate after 12 months of 2.1 per 100 women and a Pearl index of 1.63 at 27 months after the sterilization process. The complications and adverse events appear to be similar to those which occur during insertion of an IUD and were minor and transient, disappearing within a few hours or at most 2 days after the procedure.

PIP: A group of 147 women participated in a study of outpatient tubal occlusion with quinacrine pellets at a hospital in Santiago, Chile. Six pellets, each containing 36 mg of quinacrine, were inserted transcervically into the uterus by means of a plastic tube in a procedure resembling IUD insertion. The women also received 50 mg of intrauterine diclofenac and 150 mg of intramuscular diclofenac. The initial procedure was carried out within the first postmenstrual cycle week, and was repeated at the same cycle phase on month later. No procedures were done within 42 postpartum days. The study women were 34.9 years old an average and had an average of 4.9 living children. Of the 159 patients who completed the two scheduled insertions, 140 were followed for 27 months and the other 19 were lost to follow-up. Three women became pregnant within two years. The Pearl index was 1.63 for 2198 woman-months. The percentages of pregnancies were 0.62 for the first year and 1.25 for the second year. None of the pregnancies was ectopic. One pregnancy was terminated by a medical abortion, and the patient was surgically sterilized. No abnormality was observed during laparotomy. The other two pregnancies terminated in normal delivery of healthy infants. Twenty women had adverse reactions during the 24 months of observation, but most were minor. No hospitalization or additional surgical procedures were required. Three women had post-insertion metrorrhagia, which lasted a maximum of two days.

Researchers assess data on long-term safety of non-surgical sterilization method.

PIP: Concerned over a possible link to cancer, researchers from Family Health International (FHI) have begun investigating the long-term safety of the chemical used for non-surgical sterilization, a study being carried out among Chilean women. In the late 1960s, the chemical quinacrine hydrochloride was found to be an effective means of occluding the Fallopian tubes for the purpose of contraceptive sterilization. This is done through the transcervical insertion of 2 quinacrine pellets, which inserted 1 month apart. The use of quinacrine has several advantages over surgical sterilization: no incision, general anesthesia, or hospitalization is required; it can be performed by paramedics on an outpatient basis; and it effectively prevents pregnancy. Quinacrine, however, also has disadvantages, including the fact that it requires 2 applications, that the sterilization cannot be reversed, and that it increases the risk of ectopic pregnancy. Additionally, the long-term safety of this contraceptive method is not yet known. From the late 1970s to 1986, 572 women in Chile took part in clinical trials of quinacrine, tests which were supported by FHI. Continuing to monitor the health of these women, FHI recently discovered 8 cases of malignancy in 6 different anatomical sites. Although it is not known whether this figures reflect a significant difference in the incidence of malignancies between the trial group and the general population, the finding has prompted the organization to undertake a study of a possible association between the use of quinacrine pellets and malignancy.^ieng