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Drug Interactions between aminophylline / ephedrine / guaifenesin / phenobarbital and dihydrotachysterol

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

PHENobarbital aminophylline

Applies to: aminophylline / ephedrine / guaifenesin / phenobarbital and aminophylline / ephedrine / guaifenesin / phenobarbital

MONITOR: Barbiturates may decrease serum levels and therapeutic effects of the methylxanthines. The mechanism is barbiturate induction of CYP450 3A4 and 1A2 hepatic metabolism of methylxanthines.

MANAGEMENT: Close observation for clinical and laboratory evidence of decreased methylxanthine effect is indicated if these drugs must be used together. Patients should be advised to notify their physician if they experience a worsening of their respiratory symptoms.

References (4)
  1. Upton RA (1991) "Pharmacokinetic interactions between theophylline and other medication (Part I)." Clin Pharmacokinet, 20, p. 66-80
  2. Bukowskyj M, Nakatsu K, Munt PW (1984) "Theophylline reassessed." Ann Intern Med, 101, p. 63-73
  3. Landay RA, Gonzalez MA, Taylor JC (1978) "Effect of phenobarbital on theophylline disposition." J Allergy Clin Immunol, 62, p. 27-9
  4. Dahlqvist R, Steiner E, Koike Y, von Bahr C, Lind M, Billing B (1989) "Induction of theophylline metabolism by pentobarbital." Ther Drug Monit, 11, p. 408-10
Moderate

PHENobarbital dihydrotachysterol

Applies to: aminophylline / ephedrine / guaifenesin / phenobarbital and dihydrotachysterol

MONITOR: Coadministration with potent CYP450 3A4 inducers and certain anticonvulsants, which are also capable of CYP450 3A4 induction, may decrease the pharmacologic effects of vitamin D and/or vitamin D analogs. In general, vitamin D is primarily biotransformed into inactive metabolites via CYP450 3A4 in the liver. Increases in the inactivation of vitamin D may be accompanied by reduced serum calcium and increased parathyroid hormone levels. Patients on long-term anticonvulsant therapy have occasionally developed osteomalacia, presumably due to interference with vitamin D and calcium metabolism. Clinical studies have documented widely varying rates of vitamin D deficiency in pediatric patients being treated with anticonvulsants, ranging from as low as 10% to as high as 79%. Case reports of low vitamin D levels associated with symptomatic hypocalcemia also exist in patients on the potent CYP450 3A4 inducer, rifampin.

MANAGEMENT: Patients receiving vitamin D and/or vitamin D analogs with potent CYP450 3A4 inducers or anticonvulsants capable of CYP450 3A4 induction should be monitored more closely for reduced vitamin D effects. Higher doses of vitamin D and/or the vitamin D analog may be necessary to achieve the desired therapeutic effect.

References (16)
  1. (2023) "Product Information. Drisdol (ergocalciferol)." Validus Pharmaceuticals LLC
  2. (2023) "Product Information. Alfacalcidol (alfacalcidol)." Strides Pharma UK Ltd
  3. (2024) "Product Information. Fultium-D3 (colecalciferol)." Internis Pharmaceuticals Ltd
  4. (2024) "Product Information. Ostelin Specialist Range Vitamin D (colecalciferol)." Sanofi-Aventis Healthcare Pty Ltd T/A Sanofi Consumer Healthcare
  5. (2021) "Product Information. Rocaltrol (calcitriol)." Atnahs Pharma UK Ltd
  6. (2019) "Product Information. Calcitriol (calcitriol)." Strides Pharma Inc.
  7. (2024) "Product Information. Calcitriol (GenRx) (calcitriol)." Apotex Pty Ltd
  8. (2022) "Product Information. Ergocalciferol (ergocalciferol)." RPH Pharmaceuticals AB
  9. (2020) "Product Information. Sandoz D (cholecalciferol)." Sandoz Canada Incorporated
  10. (2022) "Product Information. Zemplar (paricalcitol)." AbbVie Ltd
  11. (2012) "Product Information. Zemplar (paricalcitol)." Abbott Laboratories, Limited
  12. (2023) "Product Information. Doxercalciferol (doxercalciferol)." Chartwell RX, LLC.
  13. (2024) "Product Information. Rayaldee (calcifediol)." OPKO Pharmaceuticals LLC
  14. Kasarla SS, Garikapati V, Kumar Y, Dodoala S (2024) Interplay of vitamin D and CYP3A4 polymorphisms in endocrine disorders and cancer. https://e-enm.org/journal/view.php?doi=10.3803/EnM.2021.1349
  15. Saket S, Varasteh N, Halimi Asl AA, Saneifard H (2024) How antiepileptics may change the serum level of vitamin D, calcium, and phosphorus in children with epilepsy. https://journals.sbmu.ac.ir/ijcn/article/view/25952
  16. Leung C, warner j, Harris M, Nourse C (2016) "Symptomatic hypocalcemia secondary to rifampicin-induced hypovitaminosis D." Pediatr Infect Dis J, 35, p. 822-3
Minor

ePHEDrine aminophylline

Applies to: aminophylline / ephedrine / guaifenesin / phenobarbital and aminophylline / ephedrine / guaifenesin / phenobarbital

Ephedrine-methylxanthine combinations are used for the treatment of asthma but the efficacy of the combination has been questioned. This combination may lead to increased xanthine side effects. The mechanism is unknown, but may be related to synergistic pharmacologic effects. Patients using this combination should be closely monitored for side effects such as nausea, vomiting, tachycardia, nervousness, or insomnia. If side effects are noted, the dosage of the xanthine may need to be decreased.

References (5)
  1. Weinberger M, Bronsky E, Bensch GW, Bock GN, Yecies JJ (1975) "Interaction of ephedrine and theophylline." Clin Pharmacol Ther, 17, p. 585-92
  2. Sims JA, doPico GA, Reed CE (1978) "Bronchodilating effect of oral theophylline-ephedrine combination." J Allergy Clin Immunol, 62, p. 15-21
  3. Tinkelman DG, Avner SE (1977) "Ephedrine therapy in asthmatic children. Clinical tolerance and absence of side effects." JAMA, 237, p. 553-7
  4. Weinberger MM, Brousky EA (1974) "Evaluation of oral bronchodilator therapy in asthmatic children: bronchodilators in asthmatic children." J Pediatr, 84, p. 421-7
  5. Badiei B, Faciane J, Sly M (1975) "Effect of throphylline, ephedrine and theri combination upon exercise-induced airway obstruction." Ann Allergy, 35, p. 32-6

Drug and food interactions

Major

PHENobarbital food

Applies to: aminophylline / ephedrine / guaifenesin / phenobarbital

GENERALLY AVOID: Concurrent acute use of barbiturates and ethanol may result in additive CNS effects, including impaired coordination, sedation, and death. Tolerance of these agents may occur with chronic use. The mechanism is related to inhibition of microsomal enzymes acutely and induction of hepatic microsomal enzymes chronically.

MANAGEMENT: The combination of ethanol and barbiturates should be avoided.

References (5)
  1. Gupta RC, Kofoed J (1966) "Toxological statistics for barbiturates, other sedatives, and tranquilizers in Ontario: a 10-year survey." Can Med Assoc J, 94, p. 863-5
  2. Misra PS, Lefevre A, Ishii H, Rubin E, Lieber CS (1971) "Increase of ethanol, meprobamate and pentobarbital metabolism after chronic ethanol administration in man and in rats." Am J Med, 51, p. 346-51
  3. Saario I, Linnoila M (1976) "Effect of subacute treatment with hypnotics, alone or in combination with alcohol, on psychomotor skills related to driving." Acta Pharmacol Toxicol (Copenh), 38, p. 382-92
  4. Stead AH, Moffat AC (1983) "Quantification of the interaction between barbiturates and alcohol and interpretation of fatal blood concentrations." Hum Toxicol, 2, p. 5-14
  5. Seixas FA (1979) "Drug/alcohol interactions: avert potential dangers." Geriatrics, 34, p. 89-102
Moderate

dihydrotachysterol food

Applies to: dihydrotachysterol

MONITOR: Additive effects and possible toxicity (e.g., hypercalcemia, hypercalciuria, and/or hyperphosphatemia) may occur when patients using vitamin D and/or vitamin D analogs ingest a diet high in vitamin D, calcium, and/or phosphorus. The biologically active forms of vitamin D stimulate intestinal absorption of calcium and phosphorus. This may be helpful in patients with hypocalcemia and/or hypophosphatemia. However, sudden increases in calcium or phosphorus consumption due to dietary changes could precipitate hypercalcemia and/or hyperphosphatemia. Patients with certain disease states, such as impaired renal function, may be more susceptible to toxic side effects like ectopic calcification. On the other hand, if dietary calcium is inadequate for the body's needs, the active form of vitamin D will stimulate osteoclasts to pull calcium from the bones. This may be detrimental in a patient with reduced bone density.

MANAGEMENT: Given the narrow therapeutic index of vitamin D and vitamin D analogs, the amounts of calcium, phosphorus, and vitamin D present in the patient's diet may need to be taken into consideration. Specific dietary guidance should be discussed with the patient and regular lab work should be monitored as indicated. Calcium, phosphorus, and vitamin D levels should be kept within the desired ranges, which may differ depending on the patient's condition. Patients should also be counseled on the signs and symptoms of hypervitaminosis D, hypercalcemia, and/or hyperphosphatemia.

References (10)
  1. (2023) "Product Information. Drisdol (ergocalciferol)." Validus Pharmaceuticals LLC
  2. (2024) "Product Information. Fultium-D3 (colecalciferol)." Internis Pharmaceuticals Ltd
  3. (2024) "Product Information. Ostelin Specialist Range Vitamin D (colecalciferol)." Sanofi-Aventis Healthcare Pty Ltd T/A Sanofi Consumer Healthcare
  4. (2021) "Product Information. Rocaltrol (calcitriol)." Atnahs Pharma UK Ltd
  5. (2019) "Product Information. Calcitriol (calcitriol)." Strides Pharma Inc.
  6. (2024) "Product Information. Calcitriol (GenRx) (calcitriol)." Apotex Pty Ltd
  7. (2022) "Product Information. Ergocalciferol (ergocalciferol)." RPH Pharmaceuticals AB
  8. (2020) "Product Information. Sandoz D (cholecalciferol)." Sandoz Canada Incorporated
  9. Fischer V, Haffner-Luntzer M, Prystaz K, et al. (2024) Calcium and vitamin-D deficiency marginally impairs fracture healing but aggravates posttraumatic bone loss in osteoporotic mice. https://www.nature.com/articles/s41598-017-07511-2
  10. National Institutes of Health Office of Dietary Supplements (2024) Vitamin D https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/#h37
Moderate

ePHEDrine food

Applies to: aminophylline / ephedrine / guaifenesin / phenobarbital

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

aminophylline food

Applies to: aminophylline / ephedrine / guaifenesin / phenobarbital

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

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.

See also

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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.

Further information

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