Chapter 4

Pharmacologic contraception

 

 

 

 4.1 Hormones/steroids:

Progesterones:

ovaban, MDPA, HDPA, Progeston.prevent estrus cycle 

Mode of Action:

- Neg. feed back.- Inhibition of pituitary gonadotropin (LH, FSH and Prolactin) - Local prevention of ovarian follicle

Dose:

In Proestrus:

1 mg/1 b/day for 8 days, starting in the first 3 days of proestrus.

-if mating occurs after 3 days of treatment continue therapy, pregnancy prevented in most cases.

-In Anestrus:

-.25 mg/1 b/ day for 32 days, starting at least 7 day prior to proestrus.

Next heat postponement: - 4 to 6 months

Side effects: appetite, weight, mammary. enlargement. mild lactation, listlessness, pyometra cystic endometrial hyperplasia, mammary tumor in cats.

Contraindications:

irregular cycle, mammary. tumor-uterine disease, diabetes M.

Queens:

-not approved - 5 mg/day till estrus ceases follow with 5 mg/wk for 10 weeks

Progeston:

97% efficacy when given s/c

20-30 mg/kg Small dogs

10-13 mg/kg Large dogs

Repeat at 0,3,7, months

none to very little uterine disease and side effects

4.1.1 Androgens:

Testosterone:

Methy1 Testosterone, T. proprionate

Indications:

Prevent estrus cycle.

Mode of Action:

Inhibition of Gonadotropins

Dose:

25 mg Test proprionate per os/wk

Implants:

Silicone implants with a daily release rate of 168 ml/kg prevent estrus up to 840 days with return to normal cycling and fertility

Side effects:

  • -Clitoral Hypertrophy, Vaginitis (20%)
  • -Low volume periodic vaginal discharge in 85% bitches.
  • -Masculinity
  • -premature physeal closure
  • -Inadvertent Rx of pregnant females causes urogenital anomalies in female puppies.

    Not recommended for estrus control use in the males?

    Mobolerone: Synthetic 1 9-non-steroid compound

    Androgenic, anabolic and antigonadotropic steroid.

    95% efficacy.

Mode of Action: Antigonadotropic, blocks ovulatory release of LH.

  • Dose. < 251 b - 30 mg/day/per os
  • 26-50 1 bs - 60 mg/day/per os
  • 51-100 1bs - 120 mg/day
  • >101 1b- 180 mg/day
  • G/S and G/S x -1 80 mg/day
  • -To be given 30 days prior to proestrus next estrus after termination in 7-250 days
  • Side effects: Same as with Testosterone in Queens -
  • Thickening of cervical skin hepatotoxicity, thyroid function alterations

Contra-indications: Animals with-Kidney and Liver disease

  • -prepubical bitches
  • -pregnant animals
  • -not approved in Queens

50 mg/day prevented heat -use in male? 

4.1.2 Estrogens:

Apostcoaital contraceptive agent

Mode of Action: Delay ova transport, degenerative effects on ova

  • -Alter endometrial implantation sites, histologic structure
  • Dose: Dog = Repositol DES 1mg/1b 1.M.
  • Cat = Repositol DES 2 mg 1.M.
  • ECP 0.25 MG IM. / not approved
  • Give 3-5 day poststanding heat in Bitch 2-3 days in the poststanding heat in the cat.

Side effects:

with very high dose

  • -Persistent estrus for 7-10 days
  • -Myelosuppression -- Thrombocytopenia--> Anemia (aplastic).
  • -open cervix pyometra 1-6 wks post administration. Due to synthesis of P4 receptors in endometrium, hence potentates the effect of endogenous P4 secreted during cycle.

Contra indication:

A valuable breeding animal. 

4.1.3 Prostaglandins PGF2 alpha

Indications:

Abortion

Mode of Action:

Leutolysis.

Dose

  • Dog:3Ovg/1 b/s/c divided bid or tid for 3 days in Mid and late pregnancy
  • Cat: 3 0.5 mg/1 b s/c 24 hour apart 2 doses after 40 day of pregnancy

Side effects:

Hyperpnea Salivation, vomiting diarrhea, ataxia, possible death in 2 hours post treatment.

Contra indications:

not approved

  • Dog - early pregnancy
  • Cat - not before day 40 

4.1.4 Steroidal Compounds:

Corticosteroids D x M

Dose:

5 mg bid im for 10 days after day 30 of pregnancy

Mode of Action:

Intrauterine death and fetal resorption/abortion after D45.

Side effects:

Cushingnoid, Addisonian, Gastric ulcers, systemic Infection increase 

4.2 B NON-HORMONAL COMPOUNDS

1. 3-4-trans-2, 2-dimethy1-3- pheny1-3-4p (B-pyrrolidin-Orthoxy)- peny1- 7 methoxychroman

Mode of Action:

interferes with ovum development

Dose:

orally and parenterially given to 16 dogs with in 24 hrs post coitus.

All failed to conceive

  • 2. DL 717-1 IT or 1 12717
  • 2 - (4 - chlorophenl1 ) -s-traiazole [5, 1-a] isoquinoline.

Mode of Action:

Intrauterine death. pregnancy arrest. resorption/abortion/weakling

Dose:

2.5 mg/kg im 100% effective when given between the day of mating to 15 D of pregnancy. 

4.3 IMMUNOLOGIC METHODS

Anti LH, anti Gonadotropin releasing Hormone, and Antizona Pellicida.

Dose:

Bovine and ovine LH is male dogs.

Mode of Action:

Act against LH in 3 weeks post immunization. The duration of effect variable and unpredictable

GnRH:

Mode of Action:

Combined with Albumin molecule results in inhibition of reproductive cycle in females and sterility in males

Anti Zona Pellincida - Porcine origin

Mode of Action:

Probably inhibit fertility by preventing

  • 1.spermatozoal attachment
  • 2. blocking implantation by interfering and shedding of Zone pellucida 

4.4 SCLEROSING AGENTS

4.5% Chlorhexidine degluconate

Indication:

Chemical Vasectomy

Mode of Action:

Blockade of passage

  • -Agent injected in Caudal epididyinate of adult prepubertal dogs 

4.5 MISCELLANEOUS AGENTS: