Safety of Drugs on Pregnancy in Dogs & Cats

A: Probably safe.  Although specific studies may not have proved the safety of all drugs in dogs and cats, there are no reports of adverse effects in laboratory animals or in women.

B: Safe for use if used cautiously.  Studies in laboratory animals may have uncovered some risk, but these drugs appear to be safe in dogs and cats or these drugs are safe if they are not administered when the animal is near term.

C: These drugs may have potential risks.  Studies in people or laboratory animals have uncovered risks, and these drugs should be used cautiously, as a last resort when the benefit of therapy clearly outweighs the risks.

D: Contraindicated.  These drugs have been shown to cause congenital malformations or embryotoxicity.

Drug	Recommendation	Comments
Antimicrobial Drugs
Amikacin	C	Aminoglycoside antibiotics easily cross the placenta and may cause 8th nerve toxicity or nephrotoxicity.
Ampicillin	A	Crosses the placenta but has not been shown to be harmful to fetus.
Amoxicillin	A	Crosses the placenta but has not been shown to be harmful to fetus.
Carbenicillin	A	Crosses the placenta but has not been shown to be harmful to fetus.
Cephalosporins	A	Crosses the placenta but has not been shown to be harmful to fetus.
Chloramphenicol	C	May decrease protein synthesis in fetus, particularly in bone marrow.
Ciprofloxacin	D	Do not use during pregnancy, quinolones have been associated with articular cartilage defects.
Clavulanic acid-amoxicillin	A	Crosses the placenta but has not been shown to be harmful to fetus.
Clindamycin	A	Crosses the placenta but has not been shown to be harmful to fetus
Cloxacillin	A	Crosses the placenta but has not been shown to be harmful to fetus.
Dicloxacillin	A	Crosses the placenta but has not been shown to be harmful to fetus.
Doxycycline	D	Tetracyclines can cause bone and teeth malformation in fetus and may cause toxicity in   mother.
Enrofloxacin	D	See ciprofloxacin.
Erythromycin	A	Appears to be safe except for erythromycin estolate, which has been shown to increase the risk of hepatotoxicity in women.
Gentamicin	C	Aminoglycoside antibiotics easily cross the placenta and may cause 8th nerve toxicity or nephrotoxicity. However, specific toxicities from gentamicin have not been reported, and it may be used for a serious infection in place of a suitable alternative.
Hetacillin	A	Crosses the placenta but has not been shown to be harmful to fetus.
Kanamycin	C	Aminoglycoside antibiotics easily cross the placenta and may cause 8th nerve toxcitity or nephrotoxcitity.
Lincomycin	A	Crosses the placenta but has not been shown to cause problems in fetus.
Metronidazole	C	Teratogenic in laboaratory animals, but there is no information for dogs and cats.  It should be avoided during the first three weeks of pregnancy.
Neomycin	A	Not absorbed sufficiently to cause systemic effects after oral administration.
Oxacillin	A	Crosses the placenta but has not been shown to be harmful to fetus.
Oxytetracycline	D	Toxic to fetus and may increase risk of hepatitis in mother.
Penicillin G (benzyl penicillin)	A	Crosses the placenta but has not been shown to be harmful to fetus.
Streptomycin	D	Associated with higher incidence of 8th nerve toxicity than other aminoglycosides. See gentamicin.
Sulfonamides	B	Sulfonamides cross the placenta and have produced congenital mal-formations in rats and mice, but problems have not been reported in dogs or cats; in people, they have caused neonatal icterus when administered near term.  Avoid long-acting sulfonamides.
Tetracycline	D	Tetracyclines can cause bone and teeth malformations in fetus and may cause toxicity in mother.
Trimethoprim-sulfadiazine	B	Manufacturer states that it is safe during pregnancy in dogs.
Trimethoprim	B	Teratogenic in rats but probably safe in other species.  Folate antagonism and bone marrow depression are possible with prolonged use.
Ticarcillin	A	Crosses the placenta but has not been shown to be harmful to fetus.
Tobramycin	C	Aminoglycoside antibiotics easily cross the placenta and may cause 8th nerve toxicity or nephrotoxicity.
Tylonin	B	No information is available.
Antifungal Drugs
Amphotericin-B	C	There are no known teratogenic effects, but amphotericin is extremely toxic.  Use only if the disease is life threatening, in absence of a suitable alternative.
Griseofulvin	D	Teratogenic in rats; causes multiple skeletal & brain malformations in cats.
Ketoconazole	B	Teratogenic & embryotoxic in rats; antiandrogenic; stillbirths have been reported in dogs.
Miconazole	A	Apparently safe if applied topically.
Antiparasitic Drugs
Amitraz	C	Manufacturer states that reproduction studies have not been done; no information available.
Diethyl carbamazine	A	Manufacturer states that the drug may be given to dogs throughout gestation.
Dithiazanine iodide	B	No information is available; iodide salts may cause congenital goiter if administered for prolonged periods during pregnancy.
Fenbendazole	A	Safe.  Has been administered to pregnant bitches without producing adverse effects.
Dichlorvos	B	Caution is advised when administering cholinesterase inhibitors to pregnant animals, it should not be administered to puppies or kittens, but studies in pregnant dogs and cats suggest that there are not adverse effects during pregnancy.
Ivermectin	A	Safe.  Reproduction studies in dogs, cattle, horses, and pigs have not shown adverse effects.
Levamisole	C	No information available.
Mebendazole	A	Safe.  In reproduction studies in dogs, it was not teratogenic or embryotoxic.
Piperazine	A	Safe.  No known contraindications for the use of piperazine.
Praziquantel	A	Safe.  No adverse effects were seen when tested in pregnant dogs and cats.
Thiacetarsamide (Caparsolate sodium)		No specific information regarding toxicity to fetus is available.  It can be hepatotoxic and nephrotoxic, and heartworm adulticide should be postponed until after parturition.
Bunamidine	A	Has been administered to pregnant bitches without problems and is safe in pregnant cats.  Slight interference with spermatogenesis has been seen in male dogs.
Pyrantel	A	Safe.  Toxicity studies have not shown any adverse effects.
Thenium	A	Safe.  Manufacturer states that except in young puppies, there are no known contraindications.
Thiabendazole	B	Thiabendazole is not teratogenic in laboratory animals, but high doses have produced toxemia in ewes.
Trichlorfon	C	Caution is advised when administering organophosphates to pregnant animals.  Congenital toxicoses have been reported following administration to pregnant sows.  Manufacturer states that trichlorfon should not be administered to pregnant mares, but there are no recommendations for dogs and cats.
Anticancer Drugs
Doxorubicin hydrochloride	C	May produce malformations in newborn or embryotoxicity.
Azathioprine	C	May produce congenital malformations but has been used in pregnant women safely.  It may be a suitable alternative to other drugs when immunosuppressive therapy is required.
Chlorambucil	C	May produce malformations in newborn or embryotoxicity.
Cisplatin	C	May produce congenital malformations, embryotoxicity, or nephrotoxicity.
Cyclophosphamide	C	May produce malformations in newborn or embryotoxicity.
Methotrexate	C	May produce malformations in newborn or embryotoxicity.
Vincristine	C	May produce malformations in newborn or embryotoxicity.
Analgesic Drugs
Acetaminophen	C	Safety not established in dogs, toxic in cats.
Aspirin	C	Embryotoxicity has been seen in laboratory animals but not in other species.  Late in pregnancy it may produce         pulmonary hypertension and bleeding problems.
Flunixin meglumine	C	Safety in pregnancy has not been determined.
Gold (aurothioglucose)	D	Laboratory animal studies clearly show increased congenital mal- formations.
Ibuprofen	C	Safety in dogs and cats not established.
Indomethacin	C	Can be toxic in adult dogs; can cause premature closure of ductus arteriosus if administered near term.
Phenylbutazone	C	Safety has not been established.  Long-term use can depress bone marrow.
Salicylates	C	Embryotoxicity has been seen in laboratory animals but not                 in other species.  Late in pregnancy, it may produce         pulmonary hypertension and bleeding disorders.
Anesthetic and Pre-anesthetic Drugs
Acepromazine	B	Phenothiazines should be avoided near term, they may produce neonatal CNS depression.
Atropine	B	Crosses the placenta and has been used safely but may cause fetal tachycardia.
Butorphanol	B	Safe for short-term use.  Neonatal depression can be treated with naloxone.
Codeine	B	Safe for short-term use.  Neonatal depression can be treated with naloxone.
Diazepam	C	See anticonvulsants.
Fentanyl	B	Safe for short-term use.  Neonatal depression can be treated with naloxone.
Glycopyrrolate	B	Safe.  Does not cross placenta as readily as atropine.  Studies in rats and rabbits have not revealed teratogenic effects.
Halothane	C	Decreased learning ability has been reported in rats after in utero exposure; depression may be seen in neonates after cesarean section; excessive uterine bleeding may be seen when administered during cesarean section.
Isoflurane	B	Probably safe.  Depression may be seen in neonates after cesarean section.
Ketarnine	B	Probably safe.  Depression may be seen in puppies delivered by cesarean section, may increase intrauterine pressure and induce premature labor.
Lidocaine	A	All local anesthetics appear to be safe when used for a local nerve block or epidural anesthesia.
Meperidine	B	Opiates can produce neonatal sedation and respiratory depression, but the effects can be reversed with the administration of naloxone.
Methoxyflurane	C	Neonatal depression is seen when used for cesarean section.
Morphine	B	Opiates can produce neonatal sedation and respiratory depression, but the effects can be reversed with the administration of naloxone.
Naloxone	A	Has been shown to be safe when administered to newborns within a few minutes after birth.
Nitrous oxide	B	Probably safe. Used frequently for cesarean section without adverse effects.
Oxymorphone	B	Opiates can produce neonatal sedation and respiratory depression, but the effects can be reversed with the administration of naloxone.
Pentobarbital	D	Associated with high incidence of neonatal mortality.
Thiamylal	C	Easily crosses the placenta; all barbiturates produce respiratory depression in fetus, however, thiobarbiturates are not as toxic as pentobarbital.
Thiopental	C	Easily crosses the placenta. All barbiturates produce respiratory depression in fetus; however, thiobarbiturates are not as toxic as pentobarbital.
Gastrointestinal Drugs
Antacids	A	Safe.  Not absorbed systemically.
Antiemetics	B	Probably safe if administered short term.
Cimetidine	B	Safety has not been established, but no reports of toxicity in humans.
Dimenhydrinate	B	Safe if used short term.
Diphenhydramine	B	Safe if used short term.
Diphenoxylate	C	Studies have reported adverse effects in laboratory animals, but no adverse effects have been reported in pregnant dogs, cats, and humans.
Laxatives	B	All laxatives, except Castor Oil are considered safe if they are used short term.  Castor Oil causes premature  uterine contractions.
Loperamide	C	Same comment as diphenoxylate.
Metoclopramide	B	Safe in laboratory animals, but no studies available for cats or dogs.
Methscopolamine	C	Safety not established.
Misoprostol	D	Synthetic prostaglandin, causes a termination of pregnancy.
Prochlorperazine	B	No reports of toxicity when administered short term.
Ranitidine	B	Safety has not been established, but no reports of toxicity were reported in humans.
Sucralfate	A	Probably safe.  Not absorbed systemically.
Sulfasalazine	B	Salicylate component is not absorbed enough to produce adverse effects; sulfonamide may produce neonatal icterus when used near term.
Cardiovascular Drugs
Atropine	B	Probably safe but may produce fetal tachycardia.
Captopril	C	Has been shown to be embryotoxic in laboratory animals and goats.
Digitalis	A	Probably safe.  No adverse effects seen in humans and laboratory animals.
Furosemide	B	No adverse effects have been reported.
Dopamine	B	Probably safe at therapeutic doses.
Heparin	B	Does not appear to cross placenta.
Hydralazine	B	Probably safe.  There have been reports of minor toxicity in rats, but it has been administered safely to pregnant women.
Isoproterenol	C	May cause fetal tachycardia; beta-adrenergic drugs inhibit uterine contractions.
Lidocaine	B	Probably safe.  May cause fetal bradycardia.
Nitroglycerin	C	No information available.
Nitroprusside	C	There is a risk of fetal cyanide toxicity with prolonged use.
Procainamide	B	Probably safe.  May cause fetal bradycardia.
Propranolol	C	May cause fetal bradycardia, respiratory depression, and neonatal hypoglycemia; avoid use near term.
Quinidine	B	Probably safe.  May cause fetal bradycardia.
Theophylline	B	No reports of adverse effects.
Thiazide diuretics	C	May cause increased incidence of perinatal mortality.
Warfarin	D	Causes embryotoxicity and congenital malformations, neural tube defects in laboratory animals and humans.
Anticonvulsant Drugs
Diazepam	C	Has been associated with congenital defects in mice, rats, and people.
Phenobarbital	B	Has been associated with rare congenital defects and bleeding tendencies in newborn but may be safer than other anticonvulsants
Phenytoin	C	Teratogenic in rats, mice, and people.
Primidone	C	Same risks as phenobarbital and has been associated with increased incidence of hepatitis in adult dogs.
Valproic acid	C	May cause congenital malformations.
Muscle Relaxants
Dantrolene	C	Safety not established.
Dimethyl tubocurarine	B	Quarternary base with negligible placental transfer, it does not affect the fetus unless administered in large doses.
Gallamine	B	Quarternary base with negligible placental transfer, it does not affect the fetus unless administered in large doses.
Methocarbamol	C	Safety not established, manufacturer states that it should not be administered during pregnancy.