Thyroid extract

Thyroid extract/Drug Interactions:

  • AmiodaroneAmiodarone: Based on secondary sources, amiodarone is structurally similar to thyroid hormone and may alter the conversion of thyroxine (T4) to triiodothyronine (T3).
  • AntacidsAntacids: Based on secondary sources, antacids may bind to thyroid hormone and thereby prevent it from being absorbed.
  • Anticoagulants and antiplateletsAnticoagulants and antiplatelets: The use of thyroid hormones in patients with hypothyroidism may increase the catabolism of clotting factors, thereby increasing the risk of bleeding (18; 19). Concomitant use of anticoagulants or antiplatelets with thyroid extract may increase the risk of bleeding (18; 19).
  • AntidepressantsAntidepressants: Based on secondary sources, antidepressants may alter thyroid hormone levels in patients with normal thyroid function or in individuals taking thyroid replacements.
  • Antidiabetic agentsAntidiabetic agents: Based on secondary sources, thyroid extract may cause hyperglycemia. Theoretically, thyroid extract may interfere with the effects of antidiabetic agents.
  • Antilipemic agents, bile acid sequestrantsAntilipemic agents, bile acid sequestrants: Based on secondary sources, bile acid sequestrants may increase the catabolism of thyroid extract. Theoretically, concurrent use of thyroid extract with bile acid sequestrants may lead to a decreased response to thyroid extract.
  • Antiepileptic agents, hydantoinsAntiepileptic agents, hydantoins: Based on secondary sources, hydantoins may increase the catabolism of thyroid extract. Theoretically, concurrent use of thyroid extract with hydantoins may lead to a decreased response to thyroid extract.
  • Antiobesity agentsAntiobesity agents: Based on secondary sources, thyroid extract should not be used in the treatment of obesity or concurrently with other weight-loss agents.
  • BarbituratesBarbiturates: Based on secondary sources, barbiturates may increase the catabolism of thyroid extract. Theoretically, concurrent use of thyroid extract with barbiturates may lead to a decreased response to thyroid extract.
  • Calcium saltsCalcium salts: Based on secondary sources, calcium salts may bind to thyroid hormone and thereby prevent it from being absorbed.
  • CarbamazepineCarbamazepine: Based on secondary sources, carbamazepine may increase the catabolism of thyroid extract. Theoretically, concurrent use of thyroid extract with carbamazepine may lead to a decreased response to thyroid extract.
  • CorticosteroidsCorticosteroids: Based on secondary sources, corticosteroids are metabolized more rapidly in patients with thyroid disorders. Additionally, corticosteroids may alter thyroid levels. Theoretically, corticosteroids may alter the effects of thyroid extract.
  • Cytochrome P450 metabolized agentsCytochrome P450 metabolized agents: Based on secondary sources, thyroid extract may alter the effects of drugs metabolized through the CYP 450 system.
  • DigoxinDigoxin: Patients with hypothyroidism may be more likely to experience digoxin toxicity; those with hyperthyroidism may have a diminished response (32; 33; 34). Dose adjustments and monitoring of digoxin may be required in patients with thyroid disorders receiving thyroid hormones.
  • EstrogensEstrogens: Estrogens may increase levels of thyroxine-binding globulin, which may reduce the response to thyroid hormones (35).
  • ImmunosuppressantsImmunosuppressants: In human study, positive leukocyte migration occurred with crude thyroid extract in patients with Graves' disease and Hashimoto's thyroiditis compared to controls (36). Preliminary scientific study reported on thyroid extract as a specific stimulator of sensitized lymphocytes (37). In vitro, thyroid extract induced proliferation of a biopsy-derived T cell line (38).
  • Iron saltsIron salts: Based on secondary sources, iron salts may chelate thyroid hormones in the gastrointestinal tract and lead to reduced absorption of thyroid agents.
  • KetamineKetamine: Concomitant use of thyroid hormones and ketamine can cause adverse effects including hypertension and tachycardia (39).
  • Magnesium supplementsMagnesium supplements: Based on secondary sources, magnesium salts may bind to thyroid hormone and thereby prevent it from being absorbed.
  • RifamycinsRifamycins: Based on secondary sources, rifamycins may increase the catabolism of thyroid extract. Theoretically, concurrent use of thyroid extract with rifamycins may lead to a decreased response to thyroid extract
  • SucralfateSucralfate: Based on secondary sources, sucralfate may interfere with the absorption and reduce the bioavailability of thyroid hormones.
  • SympathomimeticsSympathomimetics: Based on secondary sources, concomitant use of sympathomimetics and thyroid hormones may enhance cardiovascular effects including increasing heart rate and blood pressure.
  • TheophyllineTheophylline: Based on secondary sources, hypothyroidism may alter clearance of theophylline. Dose adjustments in theophylline may need to be made.
  • Thyroid hormonesThyroid hormones: In a case report, a male with pseudohypoparathyroidism presenting with thyroid hormonal abnormalities was treated with thyroid extract (40). The patient responded well with hormonal abnormalities normalized. In hypothyroid women, thyroid extract increased plasma T3, free T3, T4, and free T4 (41). However, results from open-label studies do not support the use of thyroid extract for hypothyroidism (1; 2).
  • WarfarinWarfarin: The use of thyroid hormones in patients with hypothyroidism may increase the catabolism of clotting factors, thereby increasing the risk of bleeding (18; 19). Concomitant use of warfarin with thyroid extract may increase the risk of bleeding (18; 19).

    • Thyroid extract/Herb/Supplement Interactions:

  • Achyranthes asperaAchyranthes aspera: According to animal study, Achyranthes aspera increases thyroid hormone levels in male rats (42).
  • Aloe veraAloe vera: Animal studies have shown that aloe vera decreases serum levels of T3 and T4 in mice (43).
  • AntacidsAntacids: Based on secondary sources, antacids may bind to thyroid hormone and thereby prevent it from being absorbed.
  • Anticoagulants and antiplateletsAnticoagulants and antiplatelets: The use of thyroid hormones in patients with hypothyroidism may increase the catabolism of clotting factors, thereby increasing the risk of bleeding (18; 19). Concomitant use of anticoagulants or antiplatelets with thyroid extract may increase the risk of bleeding (18; 19).
  • Antidepressants, selective serotonin reuptake inhibitors (SSRIs)Antidepressants, selective serotonin reuptake inhibitors (SSRIs): Based on secondary sources, antidepressants may alter thyroid hormone levels in patients with normal thyroid function or in individuals taking thyroid replacements.
  • Antiobesity herbs and supplementsAntiobesity herbs and supplements: Based on secondary sources, thyroid extract should not be used in the treatment of obesity or concurrently with other weight-loss agents.
  • AntioxidantsAntioxidants: Based on rat study, antioxidants may have a direct effect on the thyroid gland (44). The effects of antioxidants with thyroid extract are not well understood.
  • Ashwagandha (Withania somnifera)Ashwagandha (Withania somnifera): Animal studies have shown Withania somnifera to increase T4 serum concentrations when given to female mice (45). However, a case report exists of a 32 year-old healthy woman developing thyrotoxicosis while taking capsules that contained ashwagandha herbal extract for symptoms of chronic fatigue (46).
  • Bacopa monnieriBacopa monnieri: Animal studies have shown B. monnieri to increase T4 serum concentrations in male mice (43).
  • Bael fruit(Aegle marmelos)Bael fruit(Aegle marmelos): According to animal study, bael fruit (Aegle marmelos) decreased T3 serum concentrations in male mice (43).
  • Bauhinia purpureaBauhinia purpurea: Animal studies have shown Bauhinia purpurea to increase T3 and T4 serum concentrations when given to female mice (45).
  • Betel leaf extractBetel leaf extract: Animal studies have shown low doses of betel leaf extract to decrease T4 levels but increase T3 levels in male Swiss mice (47). When given at higher doses the reverse was seen.
  • Bugleweed(Lycopus europaeus)Bugleweed(Lycopus europaeus): Bugleweed has antithyroid activity according to animal study (48; 49) and theoretically may antagonize the effects of thyroid extract.
  • Calcium supplementsCalcium supplements: Based on secondary sources, calcium salts may bind to thyroid hormone and thereby prevent it from being absorbed.
  • Cardiac glycosidesCardiac glycosides: Patients with hypothyroidism may be more likely to experience digoxin toxicity; those with hyperthyroidism may have a diminished response (32; 33; 34). Dose adjustments and monitoring of digoxin may be required in patients with thyroid disorders. The effects of thyroid extract with other cardiac glycosides is not well understood, but caution is warranted.
  • Convulvulus pluricaulisConvulvulus pluricaulis: Animal studies have shown Convulvulus pluricaulis to inhibit T3 production when given to levothyroxine-treated female mice (50).
  • Cytochrome P450 metabolized herbs and supplementsCytochrome P450 metabolized herbs and supplements: Based on secondary sources, thyroid extract may alter the effects of herbs or supplements metabolized through the CYP 450 system.
  • Fenugreek seed extract (Trigonella foenum-graecum)Fenugreek seed extract (Trigonella foenum-graecum): In animal studies, an extract from fenugreek seed inhibited T3 production in mice and rats, possibly due to the inhibition of conversion from T4 to T3 (51). Fenugreek also decreased serum glucose and thyroid hormones in animals with hyperthyroidism (52).
  • FlavonoidsFlavonoids: Based on secondary sources, flavonoids may inhibit thyroid peroxidase, the key enzyme in thyroid hormone biosynthesis (53).
  • Garlic (Allium sativum)Garlic (Allium sativum): Allium sativum decreased thyroid hormones in animals with hyperthyroidism (52).
  • Green teaGreen tea: Animal studies have shown high doses of green tea extract to cause the development of goiters in rats, presumably due to the antithyroid effects of catechins (54). Animal studies have also shown green tea extract to increase TSH concentrations and decrease T3 and T4 concentrations in rats (55).
  • Guggul (Commiphora mukul)Guggul (Commiphora mukul): In animals and in vitro, guggulsterones induced T3 production (56; 57).
  • Holy basil(Ocimum sanctum leaf extract)Holy basil(Ocimum sanctum leaf extract): Animal studies have shown Ocimum sanctum to decrease serum T4 concentrations (58).
  • HyperglycemicsHyperglycemics: Based on secondary sources, thyroid extract may cause hyperglycemia. Theoretically, thyroid extract may have additive effects when used with other agents that raise blood sugar.
  • HypoglycemicsHypoglycemics: Based on secondary sources, thyroid extract may cause hyperglycemia. Theoretically, thyroid extract may interfere with the effects of hypoglycemic agents.
  • ImmunosuppressantsImmunosuppressants: In human study, positive leukocyte migration occurred with crude thyroid extract in patients with Graves' disease and Hashimoto's thyroiditis compared to controls (36). Preliminary scientific study reported on thyroid extract as a specific stimulator of sensitized lymphocytes (37). In vitro, thyroid extract induced proliferation of a biopsy-derived T cell line (38).
  • IodineIodine: In pregnant women, amniotic fluid samples were increased in iodine in women using thyroid extract therapy (31).
  • Iron saltsIron salts: Based on secondary sources, iron salts may chelate thyroid hormones in the gastrointestinal tract and lead to reduced absorption of thyroid agents.
  • Kalanchoe brasiliensisKalanchoe brasiliensis: In in vitro studies, an aqueous extract of Kalanchoe brasiliensis was shown to inhibit thyroid peroxidase (59).
  • Lithospermum officinaleLithospermum officinale: Animal studies have shown Lithospermum officinale to inhibit the TSH-induced increase in endocytic activity of the thyroid glands, followed by a strong decline in thyroid hormone concentrations in rats (60). Inhibition of peripheral T4 deiodination also occurred.
  • Magnesium supplementsMagnesium supplements: Based on secondary sources, magnesium salts may bind to thyroid hormone and thereby prevent it from being absorbed.
  • Moringa oleiferaMoringa oleifera: Animal studies have shown Moringa oleifera leaf extract to decrease T3 and increase T4 concentrations in female rats but not in male rats (61).
  • Neem (Azardirachta indica)Neem (Azardirachta indica): Animal studies have shown high doses of neem to increase T3 and decrease T4 concentrations when given to male mice (62).
  • Olive leaf (Olea europaea)Olive leaf (Olea europaea): In rat study, olive leaf extract was shown to have a stimulatory effect on the thyroid (63).
  • PhytoestrogensPhytoestrogens: Estrogens may increase levels of thyroxine-binding globulin which may reduce the response to thyroid hormones (35).
  • RapeseedRapeseed: Animal studies have shown rapeseed meals to decrease T3 and T4 serum concentrations (64).
  • Seaweed, kelp, bladderwrackSeaweed, kelp, bladderwrack: Seaweed (kelp, bladderwrack) may increase the risk of hypothyroidism or hyperthyroidism. Concurrent use of seaweed (kelp, bladderwrack) with thyroid extract may alter thyroid hormones.
  • SoySoy: In vitro, soy bean extract has been shown to inhibit thyroid peroxidase-catalyzed reactions essential to thyroid hormone synthesis (65). Animal studies have shown soy bean meals to decrease T3 and T4 serum concentrations (64). Caution is warranted when using soy with thyroid extract.
  • SteroidsSteroids: Based on secondary sources, thyroid extract may interact with corticosteroids.
  • Thyroid agentsThyroid agents: In a case report, a male with pseudohypoparathyroidism presenting with thyroid hormonal abnormalities was treated with thyroid extract (40). The patient responded well with hormonal abnormalities normalized. In hypothyroid women, thyroid extract increased plasma T3, free T3, T4, and free T4 (41). However, results from open-label studies do not support the use of thyroid extract for hypothyroidism (1; 2).

    • Thyroid extract/Food Interactions:

  • Canola oil(rapeseed oil)Canola oil(rapeseed oil): Animal studies have shown rapeseed meals to decrease T3 and T4 serum concentrations (64).
  • Green teaGreen tea: Animal studies have shown high doses of green tea extract to cause the development of goiters in rats, presumably due to the antithyroid effects of catechins (54). Animal studies have also shown green tea extract to increase TSH concentrations and to decrease T3 and T4 concentrations in rats (55). It is not known if green tea as a beverage would have the same effect.
  • Seaweed, kelp, bladderwrackSeaweed, kelp, bladderwrack: Seaweed (kelp) may increase the risk of hypothyroidism or hyperthyroidism. Ingestion of seaweed (kelp) with thyroid extract may alter thyroid hormones.
  • SoySoy: In vitro, soy bean extract has been shown to inhibit thyroid peroxidase-catalyzed reactions essential to thyroid hormone synthesis (65). Animal studies have shown soy bean meals to decrease T3 and T4 serum concentrations (64). Caution is warranted when using soy or soy food products with thyroid extract.

    • Thyroid extract/Lab Interactions:

  • Blood glucoseBlood glucose: Based on secondary sources, thyroid extract may raise blood glucose.
  • CatecholCatechol: In children, thyroid activity has shown no effect on urinary excretion of various catechol metabolites (66).
  • Growth hormoneGrowth hormone: In primary hypothyroid patients, thyroid extract inhibited growth hormone (67).
  • IodineIodine: In pregnant women, amniotic fluid samples showed increased iodine in women using thyroid extract therapy (31).
  • IodotyrosinesIodotyrosines: Mono- and diiodotyrosines were found in the plasma of a hypothyroid subject treated with desiccated thyroid (68).
  • Monoamine metabolitesMonoamine metabolites: In obese, growth hormone deficient, or myedemic children, thyroid extract has shown no effect on urinary monoamine metabolites (69).
  • NorepinephrineNorepinephrine: In hypothyroid women, thyroid extract increased plasma norepinephrine (41).
  • Thyroid panelThyroid panel: Thyroid extract or desiccated thyroid may contain both T3 (triiodothyroninine) and T4 (thyroxine). The potency may vary between products, therefore the effects on thyroid levels may vary. According to human study, thyroid extract increased plasma T3, free T3, T4, and free T4 in hypothyroid women (41).