DRUGS THAT SUPPRESS TSH OR CAUSE CENTRAL HYPOTHYROIDISM

DRUGS THAT SUPPRESS TSH OR CAUSE CENTRAL HYPOTHYROIDISM

Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns, or for more information about this medicine. Two clinical trials were conducted, one in immunocompetent adults and one in HIV-1–infected adults. The pharmacokinetics of acyclovir after a single dose of VALTREX (1 gram) were unchanged by coadministration of multiple doses of thiazide diuretics. There are no data on the safety or effectiveness of chronic suppressive therapy of more than 1 year’s synthroid inhibitors duration in otherwise healthy patients.

One study demonstrated this effect only in type 2 diabetics who also had hypothyroidism, but not in patients with normal thyroid function (45). This effect may be through altered free T4 levels in patients who are hypothyroid (46), but the exact mechanism is not known. Using multivitamin with minerals together with levothyroxine may decrease the effects of levothyroxine. You should separate the administration of levothyroxine and multivitamin with minerals by at least 4 hours. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications.

Valtrex During Pregnancy or Breastfeeding

In addition to adverse events reported from clinical trials, the following events have been identified during postmarketing use of VALTREX. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to VALTREX. Other drugs may interact with valacyclovir, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using. Recent observational studies have suggested that metformin can lower serum TSH levels (44).

• Valtrex is used to treat cold sores in children who are at least 12 years old, or chickenpox in children who are at least 2 years old.
• Dosage recommendations for adult patients with reduced renal function are provided in Table 1 see Use In Specific Populations, CLINICAL PHARMACOLOGY.
• A small subset of medications including glucocorticoids, dopamine agonists, somatostatin analogs and rexinoids affect thyroid function through suppression of TSH in the thyrotrope or hypothalamus.
• You are encouraged to report negative side effects of prescription drugs to the FDA.

Valacyclovir Interactions

Furthermore, rexinoids may useful therapies for certain metabolic disorders including diabetes and obesity (32-34). In summary, glucocorticoids can lower serum TSH levels and decrease TSH secretion through direct effects on TRH in the hypothalamus. Chronic high dose glucocorticoids or severe Cushing’s syndrome do not appear to cause clinically significant central hypothyroidism.

Drug Interaction Classification

He was noted to have low serum T4 and T3 levels consistent with hypothyroidism, but his serum TSH was also suppressed. The bexarotene was discontinued; his thyroid function tests normalized and symptoms resolved. The timing of meals relative to your oral levothyroxine dose can affect the absorption of the medication. Therefore, levothyroxine should be taken on a consistent schedule with regard to time of day and relation to meals to avoid large fluctuations in blood levels, which may alter its effects.

• VALTREX is indicated for the treatment of herpes zoster (shingles) in immunocompetent adults.
• Safer sex practices should be used with suppressive therapy (see current Centers for Disease Control and Prevention CDC Sexually Transmitted Diseases Treatment Guidelines).
• The binding of valacyclovir to human plasma proteins ranges from 13.5% to 17.9%.
• In this review, we explore mechanisms governing TSH suppression of these drugs and the clinical relevance of these effects.

VALTREX is indicated for treatment of the initial episode of genital herpes in immunocompetent adults. The efficacy of treatment with VALTREX when initiated more than 72 hours after the onset of signs and symptoms has not been established. The pharmacokinetics of digoxin were not affected by coadministration of VALTREX 1 gram 3 times daily, and the pharmacokinetics of acyclovir after a single dose of VALTREX (1 gram) was unchanged by coadministration of digoxin (2 doses of 0.75 mg). The pharmacokinetic disposition of acyclovir delivered by valacyclovir is consistent with previous experience from intravenous and oral acyclovir. Following the oral administration of a single 1-gram dose of radiolabeled valacyclovir to 4 healthy subjects, 46% and 47% of administered radioactivity was recovered in urine and feces, respectively, over 96 hours.

Valacyclovir ?

Acyclovir is converted to a small extent to inactive metabolites by aldehyde oxidase and by alcohol and aldehyde dehydrogenase. Neither valacyclovir nor acyclovir is metabolized by cytochrome P450 enzymes. Plasma concentrations of unconverted valacyclovir are low and transient, generally becoming non-quantifiable by 3 hours after administration. Peak plasma valacyclovir concentrations are generally less than 0.5 mcg/mL at all doses. VALTREX is indicated for treatment of cold sores in pediatric patients aged greater than or equal to 12 years and for treatment of chickenpox in pediatric patients aged 2 to less than 18 years see INDICATIONS AND USAGE, DOSAGE AND ADMINISTRATION. In a pre/postnatal development study, valacyclovir was administered orally to pregnant rats (up to 200 mg/kg/day from Gestation Day 15 to Post-Partum Day 20) from late gestation through lactation.

If you have genital herpes, it is very important to prevent herpes lesions during your pregnancy, so that you do not have a genital lesion when your baby is born. Rexinoids are a subclass of vitamin A derivate drugs, or retinoids, that interact with a specific nuclear hormone receptor, the retinoid X receptor (RXR). These heterodimer partners can influence transcription of many different target genes through ligand activation of either RXR or its protein partner. Bexarotene (Targretin®) is the only rexinoid currently approved for clinical use, primarily for treatment of cutaneous T cell lymphoma (29). Bexarotene and other ‘second-generation’ rexinoids are currently being studied as therapies for other advanced malignancies including lung, breast and thyroid (30;31).

Glucocorticoids have long been known to affect serum TSH levels in humans (3;4). Physiologic levels of hydrocortisone appear to play an important role in the diurnal variation of serum TSH levels with lower levels in the morning and higher levels at night (5;6). Wilber and Utiger showed that high dose glucocorticoids suppressed serum TSH in hypothyroid patients and normal subjects (3).

VALTREX is indicated for the reduction of transmission of genital herpes in immunocompetent adults. The efficacy of VALTREX for the reduction of transmission of genital herpes beyond 8 months in discordant couples has not been established. The efficacy of VALTREX for the reduction of transmission of genital herpes in individuals with multiple partners and non-heterosexual couples has not been established. Safer sex practices should be used with suppressive therapy (see current Centers for Disease Control and Prevention CDC Sexually Transmitted Diseases Treatment Guidelines). A 76 year-old male with a diagnosis of cutaneous T cell lymphoma presented for enrollment into an open label study of oral bexarotene after failing multiple topical and systemic therapies (35). Within two weeks of starting bexarotene (650 mg/m2/day) the patient developed symptoms of hypothyrodism including cold intolerance, fatigue and depression.