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6 Interactions found for:

ProAir HFA and levothyroxine
Interactions Summary
  • 2 Major
  • 2 Moderate
  • 2 Minor
  • ProAir HFA
  • levothyroxine

Drug Interactions

No drug interactions were found for selected drugs: ProAir HFA, levothyroxine.

This does not necessarily mean no interactions exist. Always consult your healthcare provider.

Drug and Food Interactions

Moderate
Levothyroxine + Food

The following applies to the ingredients: Levothyroxine

ADJUST DOSING INTERVAL: Consumption of certain foods as well as the timing of meals relative to dosing may affect the oral absorption of T4 thyroid hormone (i.e., levothyroxine). T4 oral absorption is increased by fasting and decreased by foods such as soybean flour (e.g., infant formula), cotton seed meal, walnuts, dietary fiber, calcium, and calcium fortified juices. Grapefruit or grapefruit products may delay the absorption of T4 thyroid hormone and reduce its bioavailability. The mechanism of this interaction is not fully understood.

MANAGEMENT: Some manufacturers recommend administering oral T4 as a single daily dose, on an empty stomach, one-half to one hour before breakfast. In general, oral preparations containing T4 thyroid hormone should be administered on a consistent schedule with regard to time of day and relation to meals to avoid large fluctuations in serum levels. Foods that may affect T4 absorption should be avoided within several hours of dosing if possible. Consult local guidelines for the administration of T4 in patients receiving enteral feeding.

References

  1. "Product Information. Synthroid (levothyroxine)." Abbott Pharmaceutical PROD (2002):
  2. "Product Information. Armour Thyroid (thyroid desiccated)." Forest Pharmaceuticals (2022):
  3. Wohlt PD, Zheng L, Gunderson S, Balzar SA, Johnson BD, Fish JT "Recommendations for the use of medications with continuous enteral nutrition." Am J Health Syst Pharm 66 (2009): 1438-67

The following applies to the ingredients: Levothyroxine

ADJUST DOSING INTERVAL: Concurrent administration of calcium-containing products may decrease the oral bioavailability of levothyroxine by one-third in some patients. Pharmacologic effects of levothyroxine may be reduced. The exact mechanism of interaction is unknown but may involve nonspecific adsorption of levothyroxine to calcium at acidic pH levels, resulting in an insoluble complex that is poorly absorbed from the gastrointestinal tract. In one study, 20 patients with hypothyroidism who were taking a stable long-term regimen of levothyroxine demonstrated modest but significant decreases in mean free and total thyroxine (T4) levels as well as a corresponding increase in mean thyrotropin (thyroid-stimulating hormone, or TSH) level following the addition of calcium carbonate (1200 mg/day of elemental calcium) for 3 months. Four patients had serum TSH levels that were higher than the normal range. Both T4 and TSH levels returned to near-baseline 2 months after discontinuation of calcium, which further supported the likelihood of an interaction. In addition, there have been case reports suggesting decreased efficacy of levothyroxine during calcium coadministration. It is not known whether this interaction occurs with other thyroid hormone preparations.

MANAGEMENT: Some experts recommend separating the times of administration of levothyroxine and calcium-containing preparations by at least 4 hours. Monitoring of serum TSH levels is recommended. Patients with gastrointestinal or malabsorption disorders may be at a greater risk of developing clinical or subclinical hypothyroidism due to this interaction.

References

  1. Schneyer CR "Calcium carbonate and reduction of levothyroxine efficacy." JAMA 279 (1998): 750
  2. Singh N, Singh PN, Hershman JM "Effect of calcium carbonate on the absorption of levothyroxine." JAMA 283 (2000): 2822-5
  3. Csako G, McGriff NJ, Rotman-Pikielny P, Sarlis NJ, Pucino F "Exaggerated levothyroxine malabsorption due to calcium carbonate supplementation in gastrointestinal disorders." Ann Pharmacother 35 (2001): 1578-83
  4. Neafsey PJ "Levothyroxine and calcium interaction: timing is everything." Home Healthc Nurse 22 (2004): 338-9

Moderate
Proair Hfa + Food

The following applies to the ingredients: Albuterol (found in Proair Hfa)

MONITOR: Coadministration of two or more sympathomimetic agents may increase the risk of adverse effects such as nervousness, irritability, and increased heart rate. Central nervous system (CNS) stimulants, particularly amphetamines, can potentiate the adrenergic response to vasopressors and other sympathomimetic agents. Additive increases in blood pressure and heart rate may occur due to enhanced peripheral sympathetic activity.

MANAGEMENT: Caution is advised if two or more sympathomimetic agents are coadministered. Pulse and blood pressure should be closely monitored.

References

  1. Rosenblatt JE, Lake CR, van Kammen DP, Ziegler MG, Bunney WE Jr "Interactions of amphetamine, pimozide, and lithium on plasma norepineophrine and dopamine-beta-hydroxylase in schizophrenic patients." Psychiatry Res 1 (1979): 45-52
  2. Cavanaugh JH, Griffith JD, Oates JA "Effect of amphetamine on the pressor response to tyramine: formation of p-hydroxynorephedrine from amphetamine in man." Clin Pharmacol Ther 11 (1970): 656
  3. "Product Information. Adderall (amphetamine-dextroamphetamine)." Shire Richwood Pharmaceutical Company Inc PROD (2001):
  4. "Product Information. Tenuate (diethylpropion)." Aventis Pharmaceuticals PROD (2001):
  5. "Product Information. Sanorex (mazindol)." Novartis Pharmaceuticals PROD (2001):
  6. "Product Information. Focalin (dexmethylphenidate)." Mikart Inc (2001):
  7. "Product Information. Strattera (atomoxetine)." Lilly, Eli and Company (2002):

Drug and Pregnancy Interactions

The following applies to the ingredients: Albuterol (found in Proair Hfa)

The manufacturer makes no recommendation regarding use during pregnancy.

AU TGA pregnancy category: A
US FDA pregnancy category: Not assigned

Comments:
-There are no randomized clinical studies of albuterol use during pregnancy, but available information on pregnancy exposure by inhalation do not consistently show miscarriage or major birth defects.
-This drug is known to cross the placental barrier, as evidenced by increases in fetal heart rate.
-Beta-agonists, including this drug, may potentially interfere with uterine contractility.
-In women with poorly or moderately controlled asthma, there is an increased risk of preeclampsia in the mother and prematurity, low birth weight, and small for gestational age in the neonate. Pregnant women should be closely monitored and the dose adjusted as necessary to maintain optimal control.
-In some countries, intravenous injection presentations of this drug have been approved for delay pre-term labor (tocolytic agent) and should not be used in the management of uncomplicated premature labor.

Epidemiological studies and postmarketing case reports following inhaled administration of this drug do not consistently demonstrate a risk of major birth defects or miscarriage. In animal reproduction studies, subcutaneous administration to pregnant mice evidence of cleft palate at less than and up to 9 times the maximum recommended human daily inhalation dose (MRHDID). A study in pregnant rats demonstrated that drug-related material was transferred from the maternal circulation to the fetus. There are no controlled data in human pregnancy.
During worldwide marketing experience, various congenital anomalies, including cleft palate and limb defects, have been reported in the offspring of patients being treated with this drug. Some of the mothers were taking multiple medications during their pregnancies. A relationship between the use of this drug and congenital anomalies has not been established. Profuse uterine bleeding following spontaneous abortion has been reported after the use of this drug. Special care is required in pregnant diabetic women. The background birth defect and miscarriage risk for the indicated population is not known. In the US general population, the estimated major birth defect risk is 2 to 4% and the miscarriage risk is 15 to 20%.


A pregnancy exposure registry monitors outcomes after exposure to asthma medications during pregnancy. For more information, contact the Mothers To Baby Pregnancy Studies conducted by the Organization of Teratology Information Specialists at http://mothertobaby.org/pregnancystudies/.


AU TGA pregnancy category A: Drugs which have been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations or other direct or indirect harmful effects on the fetus having been observed.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

References

  1. Lunell NO, Joelsson I, Bjorkman U, Lamb P, Persson B "The use of salbutamol in obstetrics." Acta Obstet Gynecol Scand 55 (1976): 333-6
  2. Davies AE, Robertson MJ "Pulmonary oedema after the administration of intravenous salbutamol and ergometrine. Case report." Br J Obstet Gynaecol 87 (1980): 539-41
  3. Watson NA, Morgan B "Pulmonary oedema and salbutamol in preterm labour. Case report and literature review." Br J Obstet Gynaecol 96 (1989): 1445-8
  4. Lind T, Godfrey KA, Gerrard J, Bryson MR "Continuous salbutamol infusion over 17 weeks to pre-empt premature labour." Lancet 2 (1980): 1165-6
  5. Tan SN "Peri-partum pulmonary oedema." Anaesth Intensive Care 19 (1991): 111-3
  6. Hawker F "Five cases of pulmonary oedema associated with beta 2-sympathomimetic treatment of premature labour." Anaesth Intensive Care 12 (1984): 159-62
  7. Martin AJ "Severe unwanted effects associated with betasympathomimetics when used in the treatment of premature labour: causes, incidence and preventative measures." Br J Clin Pract 35 (1981): 325-9
  8. "Product Information. Proventil (albuterol)." Schering Corporation PROD (2002):
  9. "Product Information. Ventolin (albuterol)." Glaxo Wellcome PROD (2002):
  10. Rayburn WF, Atkinson BD, Gilbert K, Turnbull GL "Short-term effects of inhaled albuterol on maternal and fetal circulations." Am J Obstet Gynecol 171 (1994): 770-3
  11. Mcdonald CF, Burdon JGW "Asthma in pregnancy and lactation - a position paper for the thoracic society of australia and new zealand." Med J Aust 165 (1996): 485-8
  12. Dombrowski MP "Pharmacologic therapy of asthma during pregnancy." Obstet Gynecol Clin North Am 24 (1997): 559
  13. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  14. Cerner Multum, Inc. "Australian Product Information." O 0
  15. "Product Information. Albuterol Extended Release (albuterol)." Dava Pharmaceuticals Inc (2022):
  16. "Product Information. Albuterol Sulfate (albuterol)." Vista Pharm Inc (2022):
  17. "Product Information. Albuterol (albuterol)." Physicians Total Care (2022):

The following applies to the ingredients: Levothyroxine

Use is considered acceptable

AU TGA pregnancy category: A
US FDA pregnancy category: Not Assigned

Risk Summary: No increased rates of major birth defects or miscarriages have been reported with use during pregnancy; untreated hypothyroidism during pregnancy is associated with risks to the mother and fetus

Comments:
-Thyroid replacement therapy should not be discontinued during pregnancy; hypothyroidism diagnosed during pregnancy should be promptly treated.
-Monitor TSH levels and adjust doses as needed.

Animal studies have not been conducted. There is a long history of using this drug in pregnant women and this experience has not shown increased rates of fetal malformations, miscarriages or other adverse maternal or fetal outcomes. Hypothyroidism during pregnancy is associated with a higher rate of complications, including spontaneous abortion, pre-eclampsia, stillbirth and premature delivery. Maternal hypothyroidism may have an adverse effect on fetal neurocognitive development. Pregnant women taking this drug should have their TSH measured during each trimester and dose adjusted as appropriate. Patients will generally return to their pre-pregnancy dose after delivery. There are no controlled data in human pregnancy.

AU TGA pregnancy category A: Drugs which have been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations or other direct or indirect harmful effects on the fetus having been observed.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

References

  1. "Product Information. Synthroid (levothyroxine)." Abbott Pharmaceutical PROD (2002):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Pharmaceutical Society of Australia "APPGuide online. Australian prescription products guide online. http://www.appco.com.au/appguide/default.asp" (2006):
  4. Cerner Multum, Inc. "Australian Product Information." O 0

Drug and Breastfeeding Interactions

The following applies to the ingredients: Albuterol (found in Proair Hfa)

The manufacturer makes no recommendation regarding use during lactation.

Excreted into human milk: Unknown
Excreted into animal milk: Data not available

Comments:
-There is no information regarding this drug on the presence in human milk, the effects on a breastfed infant, or effects on milk production.
-Consider the developmental and health benefits of breastfeeding along with the mother's clinical need for this medication as well as any potential adverse effects from this drug or the underlying maternal condition.

References

  1. "Product Information. Proventil (albuterol)." Schering Corporation PROD (2002):
  2. "Product Information. Ventolin (albuterol)." Glaxo Wellcome PROD (2002):
  3. Mcdonald CF, Burdon JGW "Asthma in pregnancy and lactation - a position paper for the thoracic society of australia and new zealand." Med J Aust 165 (1996): 485-8
  4. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  5. Cerner Multum, Inc. "Australian Product Information." O 0
  6. "Product Information. Albuterol Extended Release (albuterol)." Dava Pharmaceuticals Inc (2022):
  7. "Product Information. Albuterol Sulfate (albuterol)." Vista Pharm Inc (2022):
  8. "Product Information. Albuterol (albuterol)." Physicians Total Care (2022):

The following applies to the ingredients: Levothyroxine

Use is considered acceptable

Excreted into human milk: Yes

Comments:
-Levothyroxine (T4) is a normal component of human milk; limited data on exogenous replacement doses during breastfeeding have not shown an adverse effect in nursing infants.
-Levothyroxine dose requirements may be increased in the postpartum period compared to prepregnancy requirements in patients with Hashimoto's thyroiditis.
-The presence of thyroid hormone in breast milk does not appear to interfere with neonatal thyroid screening.

References

  1. "Product Information. Synthroid (levothyroxine)." Abbott Pharmaceutical PROD (2002):
  2. Jansson L, Ivarsson S, Larsson I, Ekman R "Tri-iodothyronine and thyroxine in human milk." Acta Paediatr Scand 72 (1983): 703-5
  3. Moller B, Bjorkhem I, Falk O, Lantto O, Lafsson A "Identification of thyroxine in human breast milk by gas chromatography-mass spectrometry." J Clin Endocrinol Metab 56 (1983): 30-4
  4. Mizuta H, Amino N, Ichihara K, et al. "Thyroid hormones in human milk and their influence on thyroid function of breast-fed babies." Pediatr Res 17 (1983): 468-71
  5. Hahn HB, Spiekerman AM, Otto R, Hossalla DE "Thyroid function tests in neonates fed human milk." Am J Dis Child 137 (1983): 220-2
  6. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  7. Pharmaceutical Society of Australia "APPGuide online. Australian prescription products guide online. http://www.appco.com.au/appguide/default.asp" (2006):
  8. Cerner Multum, Inc. "Australian Product Information." O 0
  9. United States National Library of Medicine "Toxnet. Toxicology Data Network. http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT" (2013):

Therapeutic Duplication Warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

Switch to: Consumer Interactions

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

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