If you have any reason to suspect your pet has ingested something toxic, please contact your veterinarian or one of the other resources listed:
• ASPCA Animal Poison Control Center 24-hour hotline at (888) 426-4435
• Pet Poison Helpline® 24-hour animal poison control service at (855) 764-7661
Estrogen
Estrogen containing products, including oral contraceptives and hormone replacement therapy, can cause serious adverse effects and toxicity in pets. While ingestion of these medications pose toxicity risks, topical exposure is also concerning. Notable hair loss has been seen in animals exposed to topical hormone replacement therapy products.
Dogs and ferrets are indicated for this toxicity.
Signs and symptoms of toxicity: Clinical signs of toxicity include hair loss, female genital swelling, male genital atrophy, weakness and loss of coordination.
Toxic consumption:
In dogs, greater than 1 mg/kg (0.45 mg/lb) of estrogen may be toxic. It should be noted that oral contraceptives typically contain 0.02-0.05mg of estrogen per tablet.
| X-Small Yorkie, Chihuahua |
Small Pug, Boston Terrier, Poodle |
Medium Beagle, Scottish Terrier |
Large Boxer, Cocker Spaniel |
X-Large Retriever, German Shepherd |
XX-Large Great Dane, St. Bernard |
| 1 – 10 lbs. (0.45 – 4.6 kg) |
11 – 25 lbs. (5 – 11.4 kg) |
26 – 40 lbs. (11.8 – 18.2 kg) |
41 – 70 lbs. (18.6 – 31.8 kg) |
71 – 90 lbs. (32.3 – 40.9 kg) |
91 – 110 lbs. (41.4 – 50 kg) |
 |
 |
 |
 |
 |
 |
| > 0.45 mg | > 5 mg | > 11.8 mg | > 18.6 mg | > 32.3 mg | > 41.4 mg |
References:
– Berger D. Canine Alopecia Secondary to Human Topical Hormone Replacement Therapy in Six Dogs. J Am Anim Hosp Assoc 2015;51:136-142. DOI 10.5326/JAAHA-MS-6247
– Sontas H. Estrogen-induced myelotoxicity in dogs: A review. Can Vet J 2009;50:1054-1058.
Pet Poison Control is provided free as a public service by the American College of Veterinary Pharmacists. Today we’re asking you to support us with a small donation. If you would like to dedicate your gift in honor or memory of a pet or individual, you will have that option before checkout. Your gift of any amount helps us maintain this resource and make it available to the pharmacy and veterinary communities. Thank you!
