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Triamterene/Hydrochlorothiazide

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Active ingredients
  • Triamterene 37.5–75 mg
  • Hydrochlorothiazide 25–50 mg
Other brand names
Drug classes
Potassium-sparing Diuretic, Thiazide Diuretic
Dosage form
Tablet
Route
Oral
Prescription status
Rx (prescription)
Pregnancy
See Pregnancy Use Section
Lactation
See Lactation Use Section
Marketed in the U.S.
Since 2018
Label revision date
August 31, 2023
FDA Insert
Prescribing information, PDF file
Active ingredients
  • Triamterene 37.5–75 mg
  • Hydrochlorothiazide 25–50 mg
Other brand names
Drug classes
Potassium-sparing Diuretic, Thiazide Diuretic
Dosage form
Tablet
Route
Oral
Prescription status
Rx (prescription)
CSA schedule
Not a scheduled drug
Pregnancy
See Pregnancy Use Section
Lactation
See Lactation Use Section
Marketed in the U.S.
Since 2018
Label revision date
August 31, 2023
Manufacturer
Zydus Lifesciences Limited
Registration number
ANDA208360
NDC roots
70771-1361, 70771-1362
FDA Insert
Prescribing information, PDF file
Packaging Info (8 NDCs)
Packaging & NDC Codes (8)

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Drug Overview

Triamterene and Hydrochlorothiazide is a combination medication that includes triamterene, a potassium-conserving diuretic, and hydrochlorothiazide, a natriuretic agent. This medication is primarily used to treat high blood pressure (hypertension) and fluid retention (edema) in patients who may experience low potassium levels (hypokalemia) when taking hydrochlorothiazide alone.

By combining these two agents, Triamterene and Hydrochlorothiazide helps to manage blood pressure effectively while minimizing the risk of potassium loss, which is important for maintaining heart health and overall well-being. It can be used on its own or alongside other blood pressure medications, depending on your specific health needs.

Uses

Triamterene and hydrochlorothiazide tablets are used to help manage high blood pressure (hypertension) and fluid retention (edema) in patients who experience low potassium levels (hypokalemia) when taking hydrochlorothiazide alone. This medication is particularly beneficial for individuals who need a thiazide diuretic but cannot afford to lose potassium, such as those taking certain heart medications or with a history of irregular heartbeats.

You can take these tablets on their own or alongside other blood pressure medications, like beta-blockers, to enhance their effectiveness. It's important to note that while diuretics can be helpful in specific situations, their routine use during pregnancy is not recommended, as they do not prevent or treat pregnancy-related conditions like toxemia. If you experience swelling during pregnancy, it’s often best managed through rest and elevation of the legs rather than medication. However, in rare cases where swelling causes significant discomfort, a short course of diuretics may be appropriate.

Dosage and Administration

When taking triamterene and hydrochlorothiazide tablets, you will typically start with a dose of either one or two tablets of the 37.5 mg/25 mg strength each day, taken as a single dose. If you are prescribed the 75 mg/50 mg strength, the usual dose is one tablet daily. It's important to have your serum potassium levels monitored regularly while on this medication, as it can affect your potassium levels.

If you are currently taking hydrochlorothiazide and experience low potassium levels (hypokalemia), your doctor may switch you directly to the appropriate strength of triamterene and hydrochlorothiazide tablets. For those who need hydrochlorothiazide but cannot risk low potassium, treatment may begin with the 37.5 mg/25 mg tablets. If your blood pressure isn't adequately controlled with this dose, your doctor may increase it to two tablets of the 37.5 mg/25 mg strength or switch you to one tablet of the 75 mg/50 mg strength, both taken as a single dose. If blood pressure remains high, additional medications may be necessary. Always ensure that any changes in your medication are closely monitored by your healthcare provider.

What to Avoid

You should avoid using triamterene and hydrochlorothiazide if you have high potassium levels (5.5 mEq/liter or more), as this can lead to serious health issues. If you experience elevated potassium, it's important to stop taking this medication and switch to a thiazide diuretic instead. Additionally, do not take this medication if you are already using other potassium-sparing drugs like spironolactone or amiloride, or if you are on potassium supplements, potassium-rich diets, or salt substitutes containing potassium.

This medication is also not suitable for individuals with conditions such as anuria (the inability to produce urine), acute or chronic kidney problems, or significant renal impairment. Lastly, if you have a known allergy to triamterene, hydrochlorothiazide, or other sulfonamide-derived medications, you should not use this drug. Always consult your healthcare provider if you have any questions or concerns about your medications.

Side Effects

You may experience a range of side effects while taking this medication. Common gastrointestinal issues include nausea, vomiting, diarrhea, constipation, and changes in appetite or taste. You might also notice symptoms like drowsiness, fatigue, headaches, and dizziness. Some people report dry mouth, anxiety, or restlessness. Cardiovascular effects can include a rapid heartbeat and shortness of breath, especially if you consume alcohol or certain medications.

In rare cases, serious reactions such as anaphylaxis (a severe allergic reaction), acute renal failure, or blood disorders like leukopenia (low white blood cell count) may occur. Additionally, you could experience skin reactions, blurred vision, or muscle cramps. It's important to monitor your potassium levels, as high levels can be dangerous, particularly if you have kidney issues or other health concerns. If you notice any severe or unusual symptoms, contact your healthcare provider promptly.

Warnings and Precautions

It's important to be aware that using triamterene and hydrochlorothiazide can lead to a condition called hyperkalemia, which is an abnormal increase in potassium levels in your blood. This risk is higher if you have kidney problems, diabetes (even if your kidneys are functioning well), or if you are elderly or seriously ill. Since untreated hyperkalemia can be life-threatening, your doctor will need to monitor your potassium levels regularly, especially when you first start this medication, if your dosage changes, or if you become ill.

Make sure to keep all scheduled lab appointments for potassium level checks. If you experience any unusual symptoms or have concerns about your health while taking this medication, it's crucial to reach out to your healthcare provider for guidance.

Overdose

If you suspect an overdose of triamterene and hydrochlorothiazide, it's important to be aware of the potential signs and symptoms. These may include nausea, vomiting, weakness, dehydration, and changes in your electrolyte levels, such as high potassium (hyperkalemia) or low potassium (hypokalemia). You might also experience lethargy, which can progress to a more serious state like coma, as well as gastrointestinal irritation.

Since there is no specific antidote for this medication, treatment focuses on managing symptoms and supporting your body. If an overdose occurs, you should stop taking the medication immediately and seek medical help. Healthcare providers may induce vomiting or perform gastric lavage (a procedure to clear the stomach) and will monitor your electrolyte levels and fluid balance closely. Supportive care will be provided to maintain hydration and ensure your respiratory, cardiovascular, and kidney functions are stable. Always reach out to a healthcare professional if you have concerns about an overdose.

Pregnancy Use

It’s important to be cautious when considering the use of triamterene and hydrochlorothiazide during pregnancy. While animal studies have shown no evidence of harm to the fetus at high doses, there have been no adequate studies in pregnant women to confirm safety. Therefore, these medications should only be used if the potential benefits outweigh the risks to your baby.

Since animal studies do not always predict how humans will respond, it’s crucial to discuss with your healthcare provider whether you truly need these medications during your pregnancy. Always prioritize your health and the health of your developing baby when making decisions about medication use.

Lactation Use

If you are breastfeeding or planning to breastfeed, it's important to know that the combination of thiazides and triamterene has not been studied in nursing mothers. While triamterene has been found in animal milk, it may also appear in human breast milk. Additionally, thiazides are known to be excreted in breast milk as well.

If you find that using this combination medication is necessary, it is recommended that you stop nursing to avoid any potential risks to your baby. Always consult with your healthcare provider to discuss the best options for you and your child.

Pediatric Use

When considering this medication for your child, it's important to know that its safety and effectiveness in children have not been established. This means that there hasn't been enough research to confirm how well it works or how safe it is for pediatric patients (children and adolescents). Always consult with your child's healthcare provider to discuss any concerns and to determine the best treatment options for their specific needs.

Geriatric Use

As you age, it's important to be aware that certain medications can affect your health differently. For older adults, the risk of high potassium levels (hyperkalemia) increases, especially if you have kidney issues (renal impairment) or diabetes. If you are prescribed triamterene and hydrochlorothiazide, your doctor will likely monitor your potassium levels closely, particularly when you first start the medication, if your dosage changes, or if you become ill.

Additionally, your kidneys may not clear these medications as effectively, leading to higher levels in your bloodstream. Regular tests to check your blood urea nitrogen (BUN) and creatinine levels are essential, as these can show how well your kidneys are functioning. It's crucial to keep your healthcare provider informed about any changes in your health, as older adults may experience more pronounced effects from these medications.

Renal Impairment

If you have kidney problems, it's important to be aware that you may be at a higher risk for a condition called hyperkalemia, which is an elevated level of potassium in your blood. This risk is particularly significant if you also have diabetes, are elderly, or are dealing with severe illness.

To help manage this risk, your healthcare provider will need to monitor your serum potassium levels regularly. This is especially crucial when you first start taking medications like triamterene and hydrochlorothiazide, when your dosages change, or if you experience any illness that could affect your kidney function. Keeping a close eye on these levels can help ensure your safety and well-being.

Hepatic Impairment

If you have liver problems, it's important to know that there are no specific guidelines, dosage adjustments, or special monitoring instructions provided for your condition in the available information. This means that the medication may not have been studied in depth for its effects on individuals with liver impairment.

Always consult your healthcare provider for personalized advice and to discuss any concerns you may have regarding your liver health and medication use. They can help ensure that your treatment is safe and effective based on your individual health needs.

Drug Interactions

It's important to talk to your healthcare provider about any medications you are taking, as some can interact with each other in ways that may affect your health. For example, thiazide diuretics can enhance the effects of other blood pressure medications, but they may also reduce how well your body responds to certain substances like norepinephrine. Additionally, if you are taking lithium, combining it with diuretics can increase the risk of lithium toxicity, so it's crucial to consult your doctor before making any changes.

Be cautious if you are prescribed non-steroidal anti-inflammatory drugs (NSAIDs) while taking certain diuretics, as this combination has been linked to acute kidney issues in some patients. Furthermore, if you are using potassium-sparing diuretics alongside ACE inhibitors, there is a significant risk of high potassium levels, which can be dangerous. Regular monitoring of your potassium levels is essential in these cases. Always keep your healthcare provider informed about all medications and supplements you are using to ensure your safety.

Storage and Handling

To ensure the safety and effectiveness of your product, store it at a temperature between 20º to 25º C (68º to 77º F), which is considered a controlled room temperature. It's important to keep the product protected from light, as exposure can affect its quality. When dispensing, make sure to use a tight, light-resistant container, as specified by the United States Pharmacopeia (USP), to maintain its integrity.

Always handle the product with care, following these storage guidelines closely to ensure its proper use and safety. If you have any questions about disposal or further handling instructions, please consult the product information or your healthcare provider.

Additional Information

It's important to monitor your health while taking triamterene and hydrochlorothiazide. You should have your serum potassium levels checked regularly, especially when you first start the medication, change dosages, or if you have any illness that could affect your kidney function. Additionally, your doctor may recommend checking your serum electrolytes to spot any imbalances, as well as periodic tests for blood urea nitrogen (BUN) and creatinine, particularly if you are elderly or have liver or kidney issues.

If you're taking hydrochlorothiazide, remember to protect your skin from the sun and schedule regular skin cancer screenings. There is an increased risk of non-melanoma skin cancer, especially squamous cell carcinoma (SCC), for those on this medication, particularly in white patients who have taken high cumulative doses.

FAQ

What is Triamterene and Hydrochlorothiazide?

Triamterene and Hydrochlorothiazide is a medication that combines triamterene, a potassium-conserving diuretic, with hydrochlorothiazide, a natriuretic agent, to treat hypertension or edema.

What are the available dosages of Triamterene and Hydrochlorothiazide?

The medication is available in two strengths: 37.5 mg of triamterene and 25 mg of hydrochlorothiazide, and 75 mg of triamterene and 50 mg of hydrochlorothiazide.

How should I take Triamterene and Hydrochlorothiazide?

The usual dose for the 37.5 mg/25 mg tablets is one or two tablets daily as a single dose, while the 75 mg/50 mg tablets are typically taken as one tablet daily.

What should I monitor while taking this medication?

You should have your serum potassium levels monitored frequently, especially when starting the medication or changing dosages.

Who should not take Triamterene and Hydrochlorothiazide?

This medication should not be used in patients with elevated serum potassium levels, those with renal insufficiency, or those who are hypersensitive to triamterene or hydrochlorothiazide.

Can I use Triamterene and Hydrochlorothiazide during pregnancy?

The use of this medication during pregnancy should only be considered if the potential benefits outweigh the risks, as there are no adequate studies in pregnant women.

What are the common side effects of Triamterene and Hydrochlorothiazide?

Common side effects may include gastrointestinal issues like nausea and vomiting, central nervous system effects like dizziness and fatigue, and hypersensitivity reactions such as rash.

What should I do if I experience hyperkalemia?

If you experience symptoms of hyperkalemia, such as muscle weakness or irregular heartbeat, you should discontinue the medication and contact your doctor immediately.

Is it safe to take Triamterene and Hydrochlorothiazide with other medications?

Caution is advised when taking this medication with other potassium-conserving agents or lithium, as it may increase the risk of hyperkalemia or lithium toxicity.

What storage conditions are recommended for this medication?

Store Triamterene and Hydrochlorothiazide at 20º to 25º C (68º to 77º F) and protect it from light.

Packaging Info

The table below lists all NDC Code configurations of Triamterene and Hydrochlorothiazide, the U.S. brand-name prescription product. Columns show Packaging, Formulation Type, and Active Ingredient Strength.

Packaging configurations for Triamterene and Hydrochlorothiazide.
Details

FDA Insert (PDF)

This is the full prescribing document for Triamterene and Hydrochlorothiazide, submitted to the U.S. Food and Drug Administration (FDA). It contains official information for healthcare providers, including how to use the medication, possible side effects, and safety warnings.

View FDA-approved insert (PDF)

Description

Triamterene and hydrochlorothiazide is a combination of triamterene, a potassium-conserving diuretic, and hydrochlorothiazide, a natriuretic agent. Each Triamterene and Hydrochlorothiazide Tablet USP is available in two strengths: 37.5 mg/25 mg and 75 mg/50 mg. The 37.5 mg/25 mg formulation contains 37.5 mg of triamterene, USP, and 25 mg of hydrochlorothiazide, USP, while the 75 mg/50 mg formulation contains 75 mg of triamterene, USP, and 50 mg of hydrochlorothiazide, USP.

The tablets are intended for oral administration and include the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, D&C Yellow No. 10 Aluminum Lake, hypromellose, magnesium stearate, and microcrystalline cellulose. The 37.5 mg/25 mg tablets also contain FD&C Blue No. 1 Aluminum Lake.

Triamterene is chemically designated as 2,4,7-triamino-6-phenylpteridine, with a molecular weight of 253.26. It is soluble in formic acid, sparingly soluble in methoxyethanol, and very slightly soluble in acetic acid, alcohol, and dilute mineral acids. It is practically insoluble in water, benzene, ether, chloroform, and dilute alkali hydroxides. Hydrochlorothiazide is identified as 6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide, with a molecular weight of 297.7. Hydrochlorothiazide is very slightly soluble in water, freely soluble in sodium hydroxide solution, n-butylamine, and dimethyl formamide, sparingly soluble in methanol, and insoluble in ether, chloroform, and dilute mineral acids.

Uses and Indications

Triamterene and hydrochlorothiazide tablets, USP are indicated for the treatment of hypertension or edema in patients who develop hypokalemia while on hydrochlorothiazide monotherapy. This combination is also indicated for patients requiring a thiazide diuretic where the risk of hypokalemia must be minimized, such as those on concomitant digitalis preparations or with a history of cardiac arrhythmias. The tablets may be administered alone or in conjunction with other antihypertensive agents, including beta-blockers.

Limitations of Use: The routine use of diuretics in otherwise healthy pregnant women is not recommended, as it poses unnecessary risks to both the mother and fetus. Diuretics do not prevent the development of toxemia of pregnancy, nor is there sufficient evidence supporting their efficacy in treating established toxemia.

In cases of edema during pregnancy, which may arise from pathological causes or the physiological effects of pregnancy, thiazides may be indicated when the edema is due to pathological conditions, similar to their use in non-pregnant patients. Dependent edema resulting from venous return restriction due to an expanded uterus should be managed through elevation of the lower extremities and the use of support hose, as the use of diuretics to reduce intravascular volume in this context is illogical and unnecessary.

It is important to note that hypervolemia during normal pregnancy is typically not harmful to the mother or fetus, provided there is no underlying cardiovascular disease, and is often associated with generalized edema in many pregnant women. If this edema causes discomfort, increased recumbency may offer relief. In rare instances where extreme discomfort persists despite rest, a short course of diuretics may be appropriate for symptom relief.

Dosage and Administration

The usual dosage of triamterene and hydrochlorothiazide tablets, 37.5 mg/25 mg, is one or two tablets administered daily as a single dose, with appropriate monitoring of serum potassium levels. For the 75 mg/50 mg formulation, the recommended dosage is one tablet daily, also with serum potassium monitoring.

There is no clinical experience supporting the use of more than one 75 mg/50 mg tablet or more than two 37.5 mg/25 mg tablets daily. Administration of two 37.5 mg/25 mg tablets daily in divided doses, rather than as a single dose, may increase the risk of electrolyte imbalance and renal dysfunction.

Patients currently receiving 50 mg of hydrochlorothiazide who develop hypokalemia may be transitioned directly to one 75 mg/50 mg tablet of triamterene and hydrochlorothiazide. Similarly, patients on 25 mg of hydrochlorothiazide who experience hypokalemia may be switched to one 37.5 mg/25 mg tablet.

For patients requiring hydrochlorothiazide therapy where hypokalemia is a concern, treatment may be initiated with triamterene and hydrochlorothiazide tablets, 37.5 mg/25 mg. If optimal blood pressure control is not achieved with this dosage, the dose may be increased to two 37.5 mg/25 mg tablets daily as a single dose, or one 75 mg/50 mg tablet daily. If blood pressure remains uncontrolled, the addition of another antihypertensive agent should be considered.

Clinical studies indicate that patients taking less bioavailable formulations of triamterene and hydrochlorothiazide at daily doses of 25 mg to 50 mg hydrochlorothiazide and 50 mg to 100 mg triamterene can be safely transitioned to one 37.5 mg/25 mg tablet daily. All patients switched from less bioavailable formulations to the 75 mg/50 mg dosage should be closely monitored clinically and for serum potassium levels following the transition.

Contraindications

Triamterene and hydrochlorothiazide are contraindicated in the following situations:

Use is contraindicated in patients with elevated serum potassium levels (≥ 5.5 mEq/liter) due to the risk of hyperkalemia. If hyperkalemia develops, the medication should be discontinued, and a thiazide alone should be substituted.

The combination should not be administered to patients receiving other potassium-conserving agents, such as spironolactone or amiloride hydrochloride, or other formulations containing triamterene. Additionally, concomitant potassium supplementation, including medications, potassium-containing salt substitutes, or potassium-enriched diets, is contraindicated.

This medication is also contraindicated in patients with anuria, acute or chronic renal insufficiency, or significant renal impairment, as these conditions may exacerbate renal function.

Lastly, triamterene and hydrochlorothiazide should not be used in individuals who are hypersensitive to triamterene, hydrochlorothiazide, or other sulfonamide-derived drugs, due to the potential for severe allergic reactions.

Warnings and Precautions

Hyperkalemia, characterized by an abnormal elevation of serum potassium levels (≥ 5.5 mEq/liter), poses a significant risk with the use of potassium-conserving diuretic combinations, including triamterene and hydrochlorothiazide. This condition is particularly prevalent in patients with renal impairment, diabetes (even in the absence of renal impairment), as well as in elderly or severely ill individuals. Due to the potential for uncorrected hyperkalemia to be fatal, it is imperative that serum potassium levels are monitored at frequent intervals. This is especially critical for patients who are newly prescribed triamterene and hydrochlorothiazide, during any dosage adjustments, or in the presence of any illness that may affect renal function.

Regular monitoring of serum potassium levels is essential to ensure patient safety and to mitigate the risk of hyperkalemia. Healthcare professionals should remain vigilant in assessing these levels throughout the treatment course, particularly during the initiation of therapy or when changes in dosage occur.

Side Effects

Patients receiving treatment may experience a range of adverse reactions, which can be categorized by seriousness and frequency.

Serious adverse reactions include hypersensitivity reactions such as anaphylaxis, photosensitivity, and respiratory distress, including pneumonitis. Hematologic events such as agranulocytosis, thrombocytopenia, and aplastic anemia have also been reported. Renal complications, including acute renal failure and acute interstitial nephritis, may occur, particularly in patients with pre-existing renal impairment. Additionally, hyperkalemia, characterized by elevated serum potassium levels, poses a significant risk, especially in patients with renal impairment, diabetes, or those who are elderly or severely ill. Monitoring of serum potassium levels is essential, particularly when initiating treatment or adjusting dosages.

Common adverse reactions observed in clinical trials and postmarketing experiences include gastrointestinal disturbances such as nausea, vomiting, diarrhea, constipation, and appetite disturbance. Patients may also report central nervous system effects, including drowsiness, fatigue, insomnia, headache, and dizziness. Cardiovascular reactions such as tachycardia and orthostatic hypotension may occur, particularly when combined with alcohol, barbiturates, or narcotics.

Other notable adverse reactions include muscle cramps, weakness, and decreased sexual performance. Ophthalmic effects such as xanthopsia and transient blurred vision have been documented. Patients may also experience renal-related issues, including urine discoloration and the formation of renal stones composed of triamterene.

Elevated liver enzymes have been reported in patients receiving this treatment. Furthermore, hydrochlorothiazide, a component of the combination therapy, is associated with an increased risk of non-melanoma skin cancer, particularly squamous cell carcinoma in white patients taking large cumulative doses.

Overall, healthcare providers should remain vigilant for these adverse reactions and monitor patients accordingly to ensure their safety during treatment.

Drug Interactions

Thiazide diuretics may enhance the effects of other antihypertensive agents, potentially leading to additive hypotensive effects. Clinicians should monitor blood pressure closely when initiating or adjusting therapy with thiazides in patients already receiving antihypertensive medications.

Thiazides have been observed to decrease arterial responsiveness to norepinephrine; however, this effect does not compromise the therapeutic efficacy of norepinephrine as a pressor agent. Additionally, thiazides may increase the responsiveness to neuromuscular blocking agents such as tubocurarine, necessitating careful monitoring of neuromuscular function during concurrent use.

Concomitant use of lithium with diuretics, including thiazides, is generally contraindicated due to the potential for reduced renal clearance of lithium, which significantly increases the risk of lithium toxicity. It is advisable to consult the package insert for lithium prior to considering this combination therapy.

Caution is warranted when administering non-steroidal anti-inflammatory drugs (NSAIDs) such as indomethacin in patients receiving triamterene and hydrochlorothiazide, as acute renal failure has been reported in some cases. Monitoring of renal function is recommended in these patients.

The use of potassium-sparing agents in conjunction with angiotensin-converting enzyme (ACE) inhibitors should be approached with extreme caution due to the significantly elevated risk of hyperkalemia. Frequent monitoring of serum potassium levels is essential to mitigate this risk.

Packaging & NDC

The table below lists all NDC Code configurations of Triamterene and Hydrochlorothiazide, the U.S. brand-name prescription product. Columns show Packaging, Formulation Type, and Active Ingredient Strength.

Packaging configurations for Triamterene and Hydrochlorothiazide.
Details

Pediatric Use

Safety and effectiveness in pediatric patients have not been established. Therefore, the use of this medication in children, infants, and adolescents should be approached with caution until further data is available.

Geriatric Use

Elderly patients, particularly those aged 65 and older, are at an increased risk for hyperkalemia, especially if they have underlying renal impairment or diabetes. It is essential to monitor serum potassium levels at frequent intervals in this population, particularly when initiating treatment with triamterene and hydrochlorothiazide, when dosages are adjusted, or during any illness that may affect renal function.

In geriatric patients, the renal clearances of hydrochlorothiazide and the pharmacologically active metabolite of triamterene are often reduced, leading to increased plasma levels of these medications. Therefore, periodic assessments of blood urea nitrogen (BUN) and creatinine levels are recommended, as elevations in these parameters may occur more frequently in elderly patients.

Additionally, cumulative drug effects may be observed in elderly patients with impaired renal function, necessitating careful monitoring and potential dose modifications to ensure safety and efficacy in this vulnerable population.

Pregnancy

The use of triamterene and hydrochlorothiazide during pregnancy has not been established as safe, as there are no adequate and well-controlled studies in pregnant women. Animal reproduction studies have not been conducted to determine the potential for fetal harm specifically from the combination of triamterene and hydrochlorothiazide. However, a One Generation Study in rats, which approximated the drug composition using a 1:1 ratio of triamterene to hydrochlorothiazide at doses of 30 mg/kg/day each, demonstrated no evidence of teratogenicity. These doses were significantly higher than the Maximum Recommended Human Dose (MRHD), being 15 and 30 times the MRHD based on body weight, and 3.1 and 6.2 times the MRHD based on body-surface area.

Reproduction studies involving triamterene in rats at doses up to 20 times the MRHD based on body weight and 6 times the MRHD based on body-surface area also showed no evidence of fetal harm. Similarly, hydrochlorothiazide was administered to pregnant mice and rats during critical periods of organogenesis at doses up to 3000 mg/kg/day for mice and 1000 mg/kg/day for rats, with no observed fetal harm at these high doses.

Despite these findings in animal studies, it is important to note that animal reproduction studies are not always predictive of human response. Therefore, triamterene and hydrochlorothiazide should be used during pregnancy only if the potential benefit justifies the risk to the fetus. Healthcare professionals are advised to carefully consider the necessity of this medication in pregnant patients and to discuss potential risks with women of childbearing potential.

Lactation

Thiazides and triamterene in combination have not been studied in nursing mothers. However, triamterene has been shown to appear in animal milk, suggesting that it may also be excreted in human breast milk. Additionally, thiazides are known to be excreted in human breast milk.

If the use of the combination drug product is deemed essential, it is recommended that the lactating mother discontinue breastfeeding.

Renal Impairment

Patients with renal impairment are at an increased risk of hyperkalemia, particularly those with diabetes (even in the absence of renal impairment), elderly patients, or those who are severely ill.

Serum potassium levels should be monitored at frequent intervals in these patients, especially when initiating treatment with triamterene and hydrochlorothiazide, during any dosage adjustments, or in the presence of any illness that may affect renal function.

Hepatic Impairment

There is no available information regarding the use of this medication in patients with hepatic impairment. Consequently, there are no dosage adjustments, special monitoring requirements, or precautions specified for individuals with compromised liver function. Healthcare professionals should exercise caution and consider the lack of data when prescribing this medication to patients with liver problems.

Overdosage

In cases of overdosage with triamterene and hydrochlorothiazide, it is important to note that specific data regarding human overdosage are lacking, and no specific antidote is available. The primary concern in such situations is the potential for fluid and electrolyte imbalances.

Excessive doses of triamterene may lead to symptoms such as hyperkalemia, dehydration, nausea, vomiting, weakness, and possibly hypotension. Conversely, overdosage with hydrochlorothiazide has been associated with hypokalemia, hypochloremia, hyponatremia, dehydration, and lethargy, which may progress to coma, as well as gastrointestinal irritation.

Management of overdosage is primarily symptomatic and supportive. It is recommended that therapy with triamterene and hydrochlorothiazide be discontinued immediately. Healthcare professionals should consider inducing emesis or performing gastric lavage to mitigate the effects of the overdose.

Continuous monitoring of serum electrolyte levels and fluid balance is essential. Supportive measures should be instituted as necessary to maintain hydration, electrolyte balance, and the proper functioning of respiratory, cardiovascular, and renal systems.

Nonclinical Toxicology

Thiazides and triamterene have demonstrated the ability to cross the placental barrier, resulting in their presence in cord blood. The administration of thiazides and triamterene during pregnancy necessitates a careful evaluation of the anticipated benefits in relation to potential risks to the fetus. These risks may encompass fetal or neonatal jaundice, pancreatitis, thrombocytopenia, and possibly other adverse reactions that have been observed in adult populations.

Postmarketing Experience

Postmarketing experience has identified an association between hydrochlorothiazide and an increased risk of non-melanoma skin cancer, particularly squamous cell carcinoma (SCC). Data from a study conducted within the Sentinel System indicate that this increased risk is more pronounced in white patients who have received large cumulative doses of the medication. Specifically, the overall population exhibits an approximate risk of 1 additional case of SCC per 16,000 patients per year. In white patients who have taken a cumulative dose of 50,000 mg or more, the risk escalates to approximately 1 additional case of SCC for every 6,700 patients per year.

Patient Counseling

Healthcare providers should instruct patients taking hydrochlorothiazide to take precautions to protect their skin from sun exposure. This includes wearing protective clothing, using sunscreen with a high SPF, and avoiding prolonged sun exposure, especially during peak hours.

Additionally, healthcare providers should emphasize the importance of regular skin cancer screenings for patients on this medication. Patients should be encouraged to report any new or unusual skin changes to their healthcare provider promptly.

Storage and Handling

The product is supplied in a tight, light-resistant container as defined by the United States Pharmacopeia (USP). It should be stored at a temperature range of 20º to 25º C (68º to 77º F), in accordance with USP Controlled Room Temperature guidelines. Additionally, it is essential to protect the product from light to maintain its integrity and efficacy.

Additional Clinical Information

Serum potassium levels should be monitored frequently in patients initiating treatment with triamterene and hydrochlorothiazide, during dosage adjustments, or in the presence of conditions affecting renal function. Clinicians are advised to perform serum electrolyte determinations at appropriate intervals to identify potential imbalances. Additionally, periodic assessments of blood urea nitrogen (BUN) and creatinine levels are recommended, particularly for elderly patients and those with suspected or confirmed hepatic or renal impairments.

Patients prescribed hydrochlorothiazide should be counseled on the importance of sun protection and regular skin cancer screenings. It is important to note that hydrochlorothiazide has been linked to an increased risk of non-melanoma skin cancer, especially squamous cell carcinoma (SCC), in white patients receiving high cumulative doses. The risk for SCC in the general population is approximately one additional case per 16,000 patients annually, while for white patients on cumulative doses of 50,000 mg or more, the risk increases to about one additional case per 6,700 patients per year.

FDA Insert (PDF)

This document is the official FDA-approved prescribing information for Triamterene and Hydrochlorothiazide as submitted by Zydus Lifesciences Limited. It includes detailed information about indications, dosage, contraindications, warnings, and clinical pharmacology.

View full prescribing information (PDF)

Data Generation & Sources

This page was automatically generated and is maintained by the AllDrugs AI Data-Science Team. It was built from the FDA Structured Product Label (DailyMed) for Triamterene and Hydrochlorothiazide, retrieved by a validated AI data-extraction workflow.

All FDA-approved dosage forms and strengths are listed in the Packaging & NDC Codes section above. Regulatory status, pharmacologic class (EPC), and mechanism of action (MoA) were cross-checked against the FDA Orange Book (ANDA208360) and the NSDE NDC Directory daily file.

Note: an automated daemon monitors NSDE checksums; when the record for this NDC changes, the new file is pulled instantly and this page is refreshed.

No human clinician has reviewed this version.

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Orange Book data shown on this page are limited to Regulatory Status (Rx), Established Pharmacologic Class (EPC), and Mechanism of Action (MoA).

Regulatory data notice: Information on this page is reproduced verbatim from FDA public databases (NSDE, Orange Book, Purple Book, DailyMed SPL). NDA/ANDA drugs are FDA-approved, BLA biologics are FDA-licensed. Inclusion alone does not guarantee current market availability or imply FDA endorsement.

Medical disclaimer: This AI-generated content is provided for educational purposes only and does not constitute medical advice. Always consult a licensed healthcare professional for diagnosis or treatment decisions.