Triamterene + Hydrochlorothiazide


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO HTN Each tab/cap contains triamterene 37.5 mg and hydrochlorothiazide 25 mg: 1-2 tab/cap once daily. Each tab contains triamterene 50 mg and hydrochlorothiazide 25 mg: Initial: 1 tab/day after the morning meal. Max: 4 tab/day. Each tab/cap contains triamterene 75 mg and hydrochlorothiazide 50 mg: 1 tab/cap daily. Oedema Each tab/cap contains triamterene 37.5 mg and hydrochlorothiazide 25 mg: 1-2 tab/cap once daily. Each tab contains triamterene 50 mg and hydrochlorothiazide 25 mg: Initial: 1 tab bid. Maintenance: 1 tab/day or 2 tab on alternate days. Max: 4 tab/day. Each tab/cap contains triamterene 75 mg and hydrochlorothiazide 50 mg: 1 tab/cap daily.
Dosage Details
Oral
Hypertension
Adult: Each tab/cap contains triamterene 37.5 mg and hydrochlorothiazide 25 mg: 1-2 tab/cap once daily. Each tab contains triamterene 50 mg and hydrochlorothiazide 25 mg: Initially, 1 tab daily after the morning meal, adjust thereafter according to response. Max: 4 tab daily. Each tab/cap contains triamterene 75 mg and hydrochlorothiazide 50 mg: 1 tab/cap daily.

Oral
Oedema
Adult: Each tab/cap contains triamterene 37.5 mg and hydrochlorothiazide 25 mg: 1-2 tab/cap once daily. Each tab contains triamterene 50 mg and hydrochlorothiazide 25 mg: Initially, 1 tab bid. Maintenance: 1 tab daily or 2 tab on alternate days. Max: 4 tab daily. Each tab/cap contains triamterene 75 mg and hydrochlorothiazide 50 mg: 1 tab/cap daily.
Administration
Should be taken with food.
Contraindications
Hyperkalaemia (≥5.5 mEq/L), hypercalcaemia, diabetic ketoacidosis, Addison’s disease, progressive renal failure, increasing hepatic dysfunction. Concomitant use w/ K supplements, other K-conserving drugs, including ACE inhibitors.
Special Precautions
Patients w/ prediabetes or DM, diabetic nephropathy, predisposition to gout, history of renal lithiasis. Hepatic or renal impairment. Pregnancy and lactation.
Adverse Reactions
Nausea, vomiting, diarrhoea, dizziness, weakness, hypotension, headache, muscle cramps, dry mouth, thirst, anaphylaxis, rash, metabolic acidosis, pancreatitis. Rarely, SLE and photosensitivity.
Potentially Fatal: Hyperkalaemia.
Patient Counseling Information
This drug may cause a blue fluorescence of the urine under certain light conditions.
MonitoringParameters
Monitor BUN, BP, serum K levels and other electrolytes, creatinine, LFTs, signs of hyperkalaemia.
Overdosage
Symptoms: Electrolyte imbalance, nausea, vomiting, weakness, polyuria, lassitude, fever, flushed face, hyperactive deep tendon reflexes, hypotension, cardiac arrhythmias. Management: Induce immediate evacuation through emesis or gastric lavage. Pressor agents e.g. norepinephrine may be given in case of hypotension.
Drug Interactions
May reduce the renal clearance of lithium. May antagonise diuretic effect w/ NSAIDs, corticosteroids, oestrogens, combined OCs. Enhanced effect w/ other hypotensive agents, baclofen, tizanidine. May decrease arterial responsiveness to norepinephrine. Increases responsiveness to tubocurarine. Risk of acute renal failure w/ indometacin. Increased risk of hyperkalaemia w/ reboxetine, tacrolimus. Increased risk of ototoxicity and nephrotoxicity w/ platinum compounds (e.g. cisplatin).
Potentially Fatal: Increased risk of hyperkalaemia w/ K supplements, other K-conserving drugs, including ACE inhibitors.
Lab Interference
Interferes w/ some thyroid and parathyroid function tests, bioassay of folic acid and measurement of quinidine.
Action
Description: Triamterene directly inhibits the exchange of Na for K and hydrogen in the distal renal tubule. Hydrochlorothiazide increases the excretion of Na and Cl ions, and consequently of water, by reducing electrolyte reabsorption from the renal tubules.
Onset: W/in 1 hr.
Pharmacokinetics:
Absorption: Incompletely but fairly rapidly absorbed from the GI tract. Triamterene: Bioavailability: Approx 50%. Time to peak plasma concentration: W/in 1 hr. Hydrochlorothiazide: Bioavailability: Approx 65-70%. Time to peak plasma concentration: Approx 2 hr.
Distribution: Triamterene: Plasma protein binding: Approx 67%. Hydrochlorothiazide: Crosses the placenta and enters breast milk.
Metabolism: Triamterene: Metabolised to 6-p-hydroxytriamterene and its sulfate conjugate.
Excretion: Triamterene: Via urine (10-88%); bile (variable amounts). Plasma half-life: Approx 2 hr. Hydrochlorothiazide: Via urine as unchanged drug. Elimination half-life: Approx 3-6 hr.
Chemical Structure

Chemical Structure Image
Triamterene

Source: National Center for Biotechnology Information. PubChem Database. Triamterene, CID=5546, https://pubchem.ncbi.nlm.nih.gov/compound/Triamterene (accessed on Jan. 23, 2020)


Chemical Structure Image
Hydrochlorothiazide

Source: National Center for Biotechnology Information. PubChem Database. Hydrochlorothiazide, CID=3639, https://pubchem.ncbi.nlm.nih.gov/compound/Hydrochlorothiazide (accessed on Jan. 20, 2020)

Storage
Store between 20-25°C. Protect from light.
ATC Classification
C03EA01 - hydrochlorothiazide and potassium-sparing agents ; Belongs to the class of low-ceiling diuretics in combination with potassium-sparing agents. Used as diuretics.
References
Anon. Hydrochlorothiazide and Triamterene. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 10/03/2016.

Buckingham R (ed). Hydrochlorothiazide. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 10/03/2016.

Buckingham R (ed). Triamterene. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 10/03/2016.

McEvoy GK, Snow EK, Miller J et al (eds). Triamterene. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 10/03/2016.

Triamterene and Hydrochlorothiazide Tablet (Actavis Pharma, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 10/03/2016.

Disclaimer: This information is independently developed by MIMS based on Triamterene + Hydrochlorothiazide from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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