Proguanil

Proguanil is an antimalarial prodrug that is metabolized to the active metabolite cycloguanil, a dihydrofolate reductase (DHFR) inhibitor.

Signaling Pathways >> Anti-infection >> Parasite

Research Areas >> Infection

Proguanil per se has only weak antimalarial activity in vitro (IC50=2.4-19 μM), and its effectiveness depends on the active metabolite cycloguanil (IC50=0.5-2.5 nM). The cycloguanil is a dihydrofolate reductase (DHFR) inhibitor. The combination of atovaquone and proguanil is synergistic in vitro. Both drugs also have activity against gametocytes and pre-erythrocytic (hepatic) stages of malaria parasites[1]. Proguanil acts as a biguanide rather than as its metabolite cycloguanil (a parasite dihydrofolate reductase [DHFR] inhibitor) to enhance the atovaquone effect; proguanil-mediated enhancement is specific for atovaquone, since the effects of other mitochondrial electron transport inhibitors, such as myxothiazole and antimycin, are not altered by inclusion of proguanil[2]. 5-HT3 receptor responses are reversibly inhibited by proguanil, the metabolite 4-chlorophenyl-1-biguanide (CPB) and the active metabolite cycloguanil (CG), with an IC50 of 1.81, 1.48 and 4.36 μM, respectively[3].

Proguanil could induce infertility in rats which may act by distorting the blood-testis barrier formed by the Sertoli cells. Duration dependent significant decrease in body and organ weights and also in sperm parameters is observed. Serum testosterone level is significantly decreased for proguanil treatment rats[4]. Administration of Malarone (atovaquone and proguanil) to experimentally B. gibsoni infected two dogs in chronic stage and three dogs in acute stage results in decrease in parasitemia, and clinical improvements are observed[5].

Sertoli cells obtained from sixteen to eighteen day-old-rats are cultured and treated with 0.3 μM to 10 μM of proguanil for 5 days after which Sertoli cell viability and nuclei integrity are determined. Also, the genetic expressions of transferrin and Glial cell line-derived neurotrophic factor are assessed[4].

Rats: Groups of ten to twelve-week-old rats are administered proguanil (2.9 mg/kg body weight) daily for 5 days and 6 weeks respectively. Thereafter, body and reproductive organ weights are taken, sperm parameters are analyzed, while the histology of the testis and epididymis are carried out. Also, serum levels of testosterone, luteinizing hormone and follicle stimulating hormone are determined[4].

[1]. Pudney M, et al. Atovaquone and proguanil hydrochloride: a review of nonclinical studies. J Travel Med. 1999 May;6 Suppl 1:S8-12.

[2]. Srivastava IK, et al. A mechanism for the synergistic antimalarial action of atovaquone and proguanil. Antimicrob Agents Chemother. 1999 Jun;43(6):1334-9.

[3]. Lochner M, et al. The antimalarial drug proguanil is an antagonist at 5-HT3 receptors. J Pharmacol Exp Ther. 2014 Dec;351(3):674-84.

[4]. Stephen AO, et al. Prolonged administration of proguanil induces reproductive toxicity in male rats. J Toxicol Sci. 2011 Oct;36(5):587-99.

[5]. Iguchi A, et al. The in vitro interactions and in vivo efficacy of atovaquone and proguanil against Babesia gibsoni infection in dogs. Vet Parasitol. 2013 Nov 8;197(3-4):527-33.

Hydroxychloroquine sulfate | Metronidazole | Emetine dihydrochloride hydrate | Ivermectin | Artemisinin | Levamisole (hydrochloride) | Fluralaner | RRx-001 | Avermectin | Quinidine | Bithionol | Flubendazole | Mebendazole | SQ109 | Artemether

DATA ITEMS CITED :

14

MOLECULAR FORMULA :

C11-H16-Cl-N5

MOLECULAR WEIGHT :

253.77

WISWESSER LINE NOTATION :

GR DMYUM&MYUM&MY1&1

HEALTH HAZARD DATA

ACUTE TOXICITY DATA

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Intraperitoneal

SPECIES OBSERVED :

Rodent - rat

DOSE/DURATION :

15 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

14XBAV "International Congress of Chemotherapy, Proceedings of the 3rd Congress, 1963," Kuemmerle, H.P., and Prezios, P., Stuttgart, Fed. Rep. Ger., Georg Thieme Verlag, 1964 Volume(issue)/page/year: -,367,1964

TYPE OF TEST :

LDLo - Lowest published lethal dose

ROUTE OF EXPOSURE :

Intravenous

SPECIES OBSERVED :

Rodent - rat

DOSE/DURATION :

40 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

CLDND* Compilation of LD50 Values of New Drugs. (J.R. MacDougal, Dept. of National Health and Welfare, Food and Drug Divisions, 35 John St., Ottawa, Ont., Canada)

TYPE OF TEST :

LDLo - Lowest published lethal dose

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

50 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

CLDND* Compilation of LD50 Values of New Drugs. (J.R. MacDougal, Dept. of National Health and Welfare, Food and Drug Divisions, 35 John St., Ottawa, Ont., Canada)

TYPE OF TEST :

LDLo - Lowest published lethal dose

ROUTE OF EXPOSURE :

Intraperitoneal

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

25 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

CLDND* Compilation of LD50 Values of New Drugs. (J.R. MacDougal, Dept. of National Health and Welfare, Food and Drug Divisions, 35 John St., Ottawa, Ont., Canada)

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Intravenous

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

22 mg/kg

TOXIC EFFECTS :

Biochemical - Enzyme inhibition, induction, or change in blood or tissue levels - other esterases

REFERENCE :

BJPCAL British Journal of Pharmacology and Chemotherapy. (London, UK) V.1-33, 1946-68. For publisher information, see BJPCBM. Volume(issue)/page/year: 4,14,1949

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - rabbit

DOSE/DURATION :

150 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

CLDND* Compilation of LD50 Values of New Drugs. (J.R. MacDougal, Dept. of National Health and Welfare, Food and Drug Divisions, 35 John St., Ottawa, Ont., Canada)

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Intraperitoneal

SPECIES OBSERVED :

Rodent - rabbit

DOSE/DURATION :

50 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

CLDND* Compilation of LD50 Values of New Drugs. (J.R. MacDougal, Dept. of National Health and Welfare, Food and Drug Divisions, 35 John St., Ottawa, Ont., Canada)

TYPE OF TEST :

LDLo - Lowest published lethal dose

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Bird - chicken

DOSE/DURATION :

400 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

CLDND* Compilation of LD50 Values of New Drugs. (J.R. MacDougal, Dept. of National Health and Welfare, Food and Drug Divisions, 35 John St., Ottawa, Ont., Canada)

TYPE OF TEST :

LDLo - Lowest published lethal dose

ROUTE OF EXPOSURE :

Intravenous

SPECIES OBSERVED :

Bird - chicken

DOSE/DURATION :

60 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

CLDND* Compilation of LD50 Values of New Drugs. (J.R. MacDougal, Dept. of National Health and Welfare, Food and Drug Divisions, 35 John St., Ottawa, Ont., Canada) ** OTHER MULTIPLE DOSE TOXICITY DATA **

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

250 mg/kg/5D-I

TOXIC EFFECTS :

Related to Chronic Data - death

REFERENCE :

BJPCAL British Journal of Pharmacology and Chemotherapy. (London, UK) V.1-33, 1946-68. For publisher information, see BJPCBM. Volume(issue)/page/year: 5,438,1950 ** REPRODUCTIVE DATA **

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

DOSE :

700 mg/kg

SEX/DURATION :

female 7 day(s) pre-mating

TOXIC EFFECTS :

Reproductive - Fertility - female fertility index (e.g. # females pregnant per # sperm positive females; # females pregnant per # females mated)

REFERENCE :

MEXPAG Medicina Experimentalis. (Basel, Switzerland) V.1-11, 1959-64; V.18-19, 1968-69. For publisher information, see JNMDBO. Volume(issue)/page/year: 10,361,1964

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

DOSE :

70 mg/kg

SEX/DURATION :

female 7 day(s) pre-mating

TOXIC EFFECTS :

Reproductive - Fertility - female fertility index (e.g. # females pregnant per # sperm positive females; # females pregnant per # females mated)

REFERENCE :

TXAPA9 Toxicology and Applied Pharmacology. (Academic Press, Inc., 1 E. First St., Duluth, MN 55802) V.1- 1959- Volume(issue)/page/year: 13,228,1968

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

DOSE :

504 mg/kg

SEX/DURATION :

female 42 day(s) pre-mating

TOXIC EFFECTS :

Reproductive - Maternal Effects - ovaries, fallopian tubes

REFERENCE :

MEXPAG Medicina Experimentalis. (Basel, Switzerland) V.1-11, 1959-64; V.18-19, 1968-69. For publisher information, see JNMDBO. Volume(issue)/page/year: 10,361,1964

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

DOSE :

252 mg/kg

SEX/DURATION :

female 21 day(s) pre-mating

TOXIC EFFECTS :

Reproductive - Maternal Effects - uterus, cervix, vagina

REFERENCE :

MEXPAG Medicina Experimentalis. (Basel, Switzerland) V.1-11, 1959-64; V.18-19, 1968-69. For publisher information, see JNMDBO. Volume(issue)/page/year: 10,361,1964