Nitroimidazoles in the canine prostate, vagina, and urethra

Pharmacokinetic and pharmacodynamic studies of the effect of ketoconazole on reproductive function in male rats

A single oral dose (300 mg kg-1) of ketoconazole induced reversible immobilization of rat epididymal spermatozoa at 8-24 h after dosing. This occurred when the drug concentrations in cauda epididymal fluid and seminal plasma were at their peak (18.0 +/- 7.3 and 13.5 +/- 3.0 micrograms ml-1, respectively), and which was preceded by a peak plasma concentration (Cmax) of 64.82 +/- 2.47 micrograms ml-1 at 5.15 +/- 0.68 h (Tmax). In contrast, rete testis fluid collected from the same animals contained only minute amounts of ketoconazole (0.47 +/- 0.34 micrograms ml-1). Plasma testosterone concentration showed a sharp decline within 4 h of dosing, followed by a recovery from suppression, even after administration of a low dose (100 mg kg-1) which did not affect sperm motility. These findings suggest that ketoconazole gains access to the post-testicular sex organs and affects the mature spermatozoa therein much more readily than it affects testicular spermatogenesis. Synthesis and screening of compounds with a related molecular structure but which exhibit more pronounced spermicidal and less pronounced anti-androgenic effects are thus suggested in the hope that rapidly acting and reversible male contraceptives might be identified and developed.

The effect of ketoconazole on fertility of male rats

The effect of ketoconazole on the fertility of male rats was evaluated. Three days of oral dosing with ketoconazole at 200 mg/kg reduced fertility compared to controls. A complete loss of fertility was observed after doses of 400 mg/kg. There was no change in the testicular weight, epididymal sperm concentration or epididymal weight between the control and treatment groups. Motility was reduced in the high-dose group and forward progression was reduced in both dosing groups compared to control. These data support previous observations in the dog and primate that orally administered ketoconazole alters sperm viability. Although ketoconazole is too toxic for contraceptive application, its derivatives may be useful for this purpose.

Management of anaerobic infections

Successful management of anaerobic infection first requires an accurate diagnosis. Cytologic examination of wound exudates and inspection for characteristic clinical clues greatly facilitates an accurate initial diagnosis of anaerobic infection. Knowledge of antimicrobial activity against specific anaerobic pathogens is essential, since antibiotic susceptibility information is not routinely available. Whenever possible, antimicrobial and surgical therapy should be combined in managing anaerobic infections. Chloramphenicol, clindamycin, and metronidazole provide the most consistently reliable activity against pathogenic anaerobes, including Bacteroides. Penicillins are also generally effective, except for treatment of infections caused by penicillinase-producing strains of Bacteroides. Cephalosporins are not considered drugs of choice for anaerobic infections, although cefoxitin may in some instances be useful as monotherapy of mixed infections containing obligate anaerobes and coliform bacteria. Aminoglycosides and sulfonamides are ineffective and should be avoided for treatment of anaerobic infection.

Orally administered ketoconazole rapidly appears in seminal plasma and suppresses sperm motility

Ketoconazole has been shown to exert spermatostatic effects in vitro on ejaculated dog, monkey, and human spermatozoa. Oral administration of the compound to adult male beagle dogs (50-246 mg/kg) or rhesus monkeys (85-100 mg/kg) was associated with a decline in motility of sperm in ejaculates obtained after dosing. In dogs the decline in sperm motility was correlated with the presence of ketoconazole in the seminal plasma, although the measured concentrations of ketoconazole were no more than one tenth that needed for in vitro activity. The serum levels of testosterone in the dogs receiving oral ketoconazole were profoundly suppressed but the extreme rapidity of onset of the ex vivo effect on sperm motility, which was noted within 4 hours of dosing, makes it unlikely that testosterone withdrawal plays more than a minor role in the spermatostasis. The results in animals invite further pursuit of this novel, rapid onset, reversible, single dose use of spermatostatic agents for their potential as male contraceptives.