Amiloride in Pregnancy and Breastfeeding

Risk Factor: BM*
Class: Diuretics

Contents of this page:
Fetal Risk Summary
Breast Feeding Summary
Questions and Answers

Fetal Risk Summary

Amiloride is a potassium-conserving diuretic. In general, diuretics are not recommended in the treatment of pregnancy-induced hypertension because of the maternal hypovolemia characteristic of this disease.

Reproduction studies using amiloride alone in mice at 25 times the maximum recommended human dose (MRHD) and in rabbits at 20 times the MRHD found no evidence of fetal harm (1). The combination of acetazolamide and amiloride was found to produce abnormal development of the ureter and kidney in fetal mice when given at the critical moment of ureter development (2).

Amiloride crosses the placenta in modest amounts in mice and rabbits (1). No reports describing the human placenta passage of amiloride have been located. The molecular weight (approximately 302 for the dihydrate, monohydrochloride salt) is low enough, however, that passage to the human fetus should be expected.

Three reports of fetal exposure to amiloride have been located (3,4 and 5) . In one case, a malformed fetus was discovered after voluntary abortion in a patient with renovascular hypertension (3). The patient had been treated during the 1st trimester with amiloride, propranolol, and captopril. The left leg of the fetus ended at midthigh without distal development and no obvious skull formation was noted above the brain tissue. The authors attributed the defects to captopril.

The second case involved a 21-year-old woman with Bartter's syndrome who was maintained on amiloride (2030 mg/day) and potassium chloride (160300 mEq/day) throughout pregnancy (4). Progressive therapy with the two agents was required to maintain normal potassium levels. Mild intrauterine growth retardation was detected at 30 weeks' gestation with eventual vaginal delivery of a 6-lb 2-ounce (about 2800-g) female infant at 41 weeks' gestation. No abnormalities were noted in the infant. A normal 3500-g female infant was delivered by cesarean section at 37 weeks' gestation from a mother who had been treated throughout pregnancy with amiloride, hydrochlorothiazide, and amiodarone for severe chronic atrial fibrillation (5).

In a surveillance study of Michigan Medicaid recipients involving 229,101 completed pregnancies conducted between 1985 and 1992, 28 newborns had been exposed to amiloride during the 1st trimester (F. Rosa, personal communication, FDA, 1993). Two (7.1%) major birth defects were observed (one expected), one of which was a hypospadias. No anomalies were observed in five other categories of defects (cardiovascular, oral clefts, spina bifida, polydactyly, and limb reduction defects) for which specific data were available.

[*Risk Factor D if used in pregnancy-induced hypertension.]

Breast Feeding Summary

Amiloride is excreted in the milk of lactating rats at concentrations higher than that measured in blood (1). No reports describing the use of the diuretic in lactating humans have been located. The molecular weight (approximately 302 for the dihydrate, monohydrochloride salt) is low enough, however, that passage into milk should be expected.


  1. Product Information. Midamor. Merck, 2000.
  2. Miller TA, Scott WJ Jr. Abnormalities in ureter and kidney development in mice given acetazolamide-amiloride or dimethadione (DMO) during embryogenesis. Teratology 1992;46:54150.
  3. Duminy PC, Burger PT. Fetal abnormality associated with the use of captopril during pregnancy. S Afr Med J 1981;60:805.
  4. Almeida OD Jr, Spinnato JA. Maternal Bartter's syndrome and pregnancy. Am J Obstet Gynecol 1989;160:12256.
  5. Robson DJ, Jeeva Raj MV, Storey GCA, Holt DW. Use of amiodarone during pregnancy. Postgrad Med J 1985;61:757.

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Questions and Answers

What is Cyanuric Acid and Amilorine and Amiloride doing in the cat food and dog food?, Melamine- Fertilizer
Cyanuric Acid- Pool Cholrine
Amilorine- Hypertention Drug
These are the toxins that were found in the food and the bottom 3 are the news ones that they found.
I read this in Pet this morning.

cyanuric acid is not pool chlorine, it is a chlorine stabalizer to buffer it from the sun

what is the primary class of Amiloride?,

Antihypertensives and then diuretics.

Hope that will help answer your question.

what are the side effects when using amiloride/HCTZ?, especially the itchy throat cough


What side effects can this medication cause?

Although side effects from amiloride and hydrochlorothiazide are not common, they can occur. Tell your doctor if any of these symptoms are severe or do not go away:

upset stomach
loss of appetite
stomach pain
frequent urination

If you experience any of the following symptoms, call your doctor immediately:

muscle weakness or cramps
slow or irregular heartbeat
sore throat
unusual bleeding or bruising
yellowing of the skin or eyes
skin rash
difficulty breathing or swallowing

and from

What are the possible side effects of amiloride?
• Stop taking amiloride and seek emergency medical attention if you experience any of the following serious side effects:
· an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);
· an irregular heartbeat, shortness of breath, fatigue, confusion, weakness, numbness, or tingling (caused by high levels of potassium in your blood); or
· decreased urination.
• Other, less serious side effects may be more likely to occur. Continue to take amiloride and talk to your doctor if you experience
· headache or dizziness;
· nausea, diarrhea, a decrease in appetite, or bloating;
· dry mouth;
· muscle cramps; or
· lowering of the voice, excessive hair growth, or enlarged breasts.
• Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

Did you hear that there was 6 poisons in the pet food?, Aminopterin
cyanuric Acid
I heard about 4 of them but not the 6th one.

Where did you get this information?? I would be curious to read the story

Does anybody know why liquorice interacts with co-amilofruse?, I've got a feeling it has something to do with the potassium sparing property of amiloride and the high potassium content of liquorice causing potential hyperkalaemia but I'd be grateful if anyone could shed some light on this so I can share the info with some inquisitive patients.

Hi there.

Its generally not a good idea to take Co-Amilofruse with liquorice. Not only because liquorice is nasty (I'm a hater), but also because both have properties which result in potassium increase. This can lead to hyperkalaemia. Taken together, can also result in liver failure due to a higher concentration of sodium. Blood pressure would also be affected due to a greater volume of circulating fluid (hypervolaemia).

HTH Fozbah ;-)