Solution 0.22% (2.2 mg/mL)
CAUTION: Federal law restricts this drug
to use by or on the order of a licensed veterinarian.
DESCRIPTION: Regu-Mate® (altrenogest)
Solution 0.22% contains the active synthetic
progestin, altrenogest. The chemical name
4,9,11-trien-3-one. The CAS Registry Number
is 850-52-2. The chemical structure is:
mL of Regu-Mate® (altrenogest)
Solution 0.22% contains 2.2 mg of
altrenogest in an oil solution.
ACTIONS: Regu-Mate® (altrenogest)
Solution 0.22% produces a
progestational effect in mares.
INDICATIONS: Regu-Mate® (altrenogest)
Solution 0.22% is indicated to suppress estrus in mares. Suppression of estrus
allows for a predictable occurrence of estrus following drug withdrawal.
This facilitates the attainment of regular cyclicity during the transition from winter anestrus
to the physiological breeding season. Suppression of estrus will also facilitate management
of prolonged estrus conditions. Suppression of estrus may be used to facilitate
scheduled breeding during the physiological breeding season.
CONTRAINDICATIONS: Regu-Mate® (altrenogest)
Solution 0.22% is contraindicated for use in mares having a previous or current history
of uterine inflammation (i.e., acute, subacute, or chronic endometritis). Natural or synthetic
gestagen therapy may exacerbate existing low-grade or “smoldering” uterine
inflammation into a fulminating uterine infection in some instances.
synthetic progestins, including altrenogest, when administered to rats during the
embryogenic stage of pregnancy at doses manyfold greater than the recommended
equine dose caused fetal anomalies, specifically masculinization of the female genitalia.
AND ADMINISTRATION: While wearing protective gloves, remove
shipping cap and seal; replace with enclosed plastic dispensing
cap. Remove cover from bottle dispensing tip and connect luer
lock syringe (without needle). Draw out appropriate volume of
Regu-Mate solution. (Note: Do not remove syringe while bottle
is inverted as spillage may result.) Detach syringe and administer solution
orally at the rate of 1 mL per 110 pounds body weight (0.044 mg/kg) once
daily for 15 consecutive days. Administer solution directly on the base of the
mare’s tongue or on the mare’s usual grain ration. Replace cover on bottle dispensing tip to prevent leakage. Excessive
use of a syringe may cause the syringe to stick; therefore, replace syringe as necessary.
WHICH MARES WILL RESPOND TO REGU-MATE® (altrenogest)
SOLUTION 0.22%: Extensive clinical trials have demonstrated
that estrus will be suppressed in approximately 95% of the
mares within three days; however, the post-treatment response
depended on the level of ovarian activity when treatment was
initiated. Estrus in mares exhibiting regular estrus cycles
during the breeding season will be suppressed during treatment;
these mares return to estrus four to five days following
treatment and continue to cycle normally. Mares in winter anestrus
with small follicles continued in anestrus and failed to exhibit
normal estrus following withdrawal.
Response in mares in the transition phase between winter anestrus and the summer breeding season depended on the degree of follicular activity. Mares with inactive ovaries and small follicles failed to respond with normal cycles post-treatment, whereas a higher proportion of mares with ovarian follicles 20 mm or greater in diameter exhibited normal estrus cycles post-treatment. Regu-Mate® (altrenogest) Solution 0.22% was very effective
for suppressing the prolonged estrus behavior frequently observed in mares during the transition period (February, March and
April). In addition, a high proportion of these mares responded with regular estrus cycles post-treatment.
SPECIFIC USES FOR REGU-MATE® (altrenogest) SOLUTION 0.22%:
SUPPRESSION OF ESTRUS TO:
- Facilitate attainment of regular cycles during the transition period from
winter anestrus to the physiological breeding season. To facilitate attainment of regular cycles
during the transition phase, mares should be examined to determine the degree of ovarian activity. Estrus
in mares with inactive ovaries (no follicles greater than 20 mm in diameter) will be suppressed but these mares may not begin regular cycles
following treatment. However, mares with active ovaries (follicles greater
than 20 mm in diameter) frequently respond with regular post-treatment estrus cycles.
- Facilitate management of the mare exhibiting prolonged estrus during the transition
period. Estrus will be suppressed in mares exhibiting prolonged behavioral
estrus either early or late during the transition period. Again, the posttreatment
response depends on the level of ovarian activity. The mares with greater ovarian
activity initiate regular cycles and conceive sooner than the inactive mares.
Regu-Mate® (altrenogest) Solution 0.22% may
be administered early in the transition period to suppress estrus in mares with inactive ovaries
to aid in the management of these mares or to mares later in the transition period with active ovaries to prepare
and schedule the mare for breeding.
Permit scheduled breeding of mares during the physiological breeding season. To permit scheduled breeding, mares
which are regularly cycling or which have active ovarian function should be given Regu-Mate® (altrenogest)
Solution 0.22% daily for 15 consecutive days beginning 20 days before the date of the planned estrus.
Ovulation will occur 5 to 7 days following the onset of estrus as expected for nontreated mares. Breeding should follow usual procedures for mares in estrus.
Mares may be regulated and scheduled either individually or in groups.
3-year well controlled reproductive safety
study was conducted in 27 pregnant mares,
and compared with 24 untreated control
mares. Treated mares received 2 mL Regu-Mate® (altrenogest)
Solution 0.22% /110 lb body weight (2x
dosage recommended for estrus suppression)
from day 20 to day 325 of gestation.
This study provided the following data:
- In filly offspring
(all ages) of treated mares, clitoral
size was increased.
- Filly offspring from
treated mares had shorter interval from
Feb. 1 to first ovulation than fillies
from their untreated mare counterparts.
- There were no significant
differences in reproductive
performance between treated and
untreated animals (mares & their
respective offspring) measuring the
- interval from Feb. 1 to first ovulation, in mares only.
- mean interovulatory interval from first to second cycle and second to third cycle, mares only.
- follicle size, mares only.
- at 50 days gestation, pregnancy rate in treated mares was 81.8% (9/11) and untreated mares was 100% (4/4).
- after 3 cycles, 11/12 treated mares were pregnant (91.7%) and 4/4 untreated mares were pregnant (100%).
- colt offspring of treated and control mares reached puberty at approximately the same age (82 & 84 weeks respectively).
- stallion offspring from treated and control mares showed no differences in seminal volume, spermatozoal concentration, spermatozoal motility, and total sperm per ejaculate.
- stallion offspring from treated and control mares showed no difference in sexual behavior.
- testicular characteristics (scrotal width, testis weight, parenchymal weight, epididymal weight and height, testicular height, width & length) were the same between stallion offspring of treated and control mares.
Shoemaker, C.F., E.L. Squires, and R.K. Shideler. 1989.
Safety of Altrenogest in Pregnant Mares
and on Health and Development of Offspring. Eq. Vet. Sci. (9); No. 2: 69-72.
Squires, E.L., R.K. Shideler, and A.O. McKinnon. 1989.
Reproductive Performance of Offspring from mares Administered Altrenogest During Gestation. Eq. Vet. Sci.(9); No. 2: 73-76.
WARNING: Do not use in horses intended for food.
HUMAN WARNINGS: Skin contact must be avoided as Regu-Mate® (altrenogest)
Solution 0.22% is readily absorbed through unbroken skin. Protective
gloves must be worn by all persons
handling this product.
Pregnant women or women who suspect they
are pregnant should not handle Regu-Mate® (altrenogest) Solution
Women of child bearing age
should exercise extreme caution when handling this product. Accidental absorption could lead
to a disruption of the menstrual cycle or prolongation of pregnancy. Direct contact with the skin should therefore be avoided. Accidental spillage
on the skin should be washed off immediately with soap and water.
INFORMATION FOR HANDLERS:
WARNING: Regu-Mate® (altrenogest)
Solution 0.22% is readily absorbed by the skin.
Skin contact must be avoided; protective
gloves must be worn when handling this
of Overexposure: There has been no human use of this specific
product. The information contained in this section is extrapolated
from data available on other products of the same pharmacological class
that have been used in humans. Effects anticipated are due to the progestational
activity of altrenogest. Acute effects after a single exposure are
possible; however, continued daily exposure has the potential for more
untoward effects such as disruption of the menstrual cycle, uterine
or abdominal cramping, increased or decreased uterine bleeding, prolongation
of pregnancy and headaches. The oil base may also cause complications
if swallowed. In addition, the list of people who should not handle
this product (see below) is based upon the known effects of progestins
used in humans on a chronic basis.
PEOPLE WHO SHOULD NOT HANDLE THIS PRODUCT.
- Women who are or suspect they are pregnant.
- Anyone with thrombophlebitis or thromboembolic disorders or with a history of these events.
- Anyone with cerebral-vascular or coronary artery disease.
- Women with known or suspected carcinoma of the breast.
- People with known or suspected estrogen-dependent neoplasia.
- Women with undiagnosed vaginal bleeding.
- People with benign or malignant tumors which developed during the use
of oral contraceptives or other estrogen-containing products.
- Anyone with liver dysfunction or disease.
ACCIDENTAL EXPOSURE: Altrenogest
is readily absorbed from contact with the skin. In addition, this oil based product can penetrate porous gloves. Altrenogest should not penetrate
intact rubber or impervious gloves; however, if there is leakage (i.e., pinhole, spillage, etc.), the contaminated area covered by such occlusive materials
may have increased absorption. The following measures are recommended in case of accidental exposure.
Skin Exposure: Wash immediately with soap and water.
Eye Exposure:Immediately flush with plenty of water for 15 minutes. Get medical attention.
If Swallowed: Do not induce vomiting. Regu-Mate® (altrenogest) Solution 0.22% contains an oil. Call a physician. Vomiting
should be supervised by a physician because of possible pulmonary damage via aspiration of the oil base. If possible, bring the container and labeling to the physician.
CAUTION: For oral use in horses only. Keep this and all medication out of the reach of children.
Store at or below 25°C (77°F).
Regu-Mate® (altrenogest) Solution 0.22% (2.2 mg/mL).
Each mL contains 2.2 mg altrenogest in an oil solution.
Available in 1000 mL plastic bottles.
* US Patents 3,453,267; 3,478,067; 3,484,462
DPT Laboratories, San Antonio, TX 78215
Intervet Inc., Millsboro, DE 19966
NADA 131-310, Approved by FDA