Triamterene caps 50mg
- Drugs List
- Therapeutic Indications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
Oral formulations triamterene
Diuresis (potassium sparing) required due to corticosteroid therapy
Oedema due to cardiac failure
Oedema due to liver failure
Oedema due to nephrotic syndrome
Potassium conservation when given with thiazide or loop diuretic
When given alone, the usual total daily dose range is 150 mg to 250 mg triamterene daily, with 200 mg being the optimum total daily dose on treatment days.
For the first week the total daily dose should be divided between a dose after breakfast and a second dose after lunch.
After the first week dosing should be given on alternate days to ensure adequate maintenance diuresis without increases in blood urea levels.
When given with another diuretic, lower doses of both diuretics should normally be used initially.
(See Dosage; Adult).
Elderly patients should receive lower initial doses.
Patients with Renal Impairment
The Renal Drug Handbook suggests the following:
Glomerular Renal Function
GFR below 20 ml/minute: Avoid
Hyperkalaemia is common in patients with GFR less than 30 ml/minute. May cause acute kidney injury.
Children under 18 years
Progressive hepatic disorder
Progressive renal disorder
Renal impairment - glomerular filtration rate below 20ml/minute
Precautions and Warnings
Glucose-galactose malabsorption syndrome
Monitor blood urea
Monitor patients at risk of gout
Monitor serum electrolytes
May impart blue colour to urine
May affect results of some laboratory tests
Advise patient not to take NSAIDs unless advised by clinician
Advise on problems of salt substitutes/high intake of potassium-rich food
Pregnancy and Lactation
Triamterene should only be used during pregnancy if absolutely necessary.
Triamterene crosses the human placenta. Many sources contraindicate the use of diuretics during pregnancy, except for patients with heart disease. This is because they do not prevent or alter the course of toxaemia and they may decrease placental perfusion. No specific teratogenic action of triamterene has been recognised to date. Diuretics are not recommended to treat hypertension during pregnancy due to the maternal, hypovolaemic character of the disease. If a diuretic must be given during pregnancy then hydrochlorothiazide is the diuretic of choice. If long term treatment is necessary the mother's electrolytes and haematocrit should be measured and the development of oligohydramnios should be ruled out. Hypoglycaemia in the newborn should also be determined. Briggs (2011) concludes that there is a risk associated with triamterene.
The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Triamterene is contraindicated in breastfeeding.
Triamterene passes into breast milk. The lack of experience with this drug whilst breastfeeding mean that the potential effects on the infant are unknown. Schaefer (2007) recommends that this drug is not used during breastfeeding due to insufficient data. Hale (2013) recommends that because of the availability of other less dangerous diuretics, triamterene should only be used as a last resort in breastfeeding mothers.
Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
Specialist advice is available from the UK Drugs in Lactation Advisory Service at https://www.midlandsmedicines.nhs.uk/content.asp?section=6&subsection=17&pageIdx=1
Acute interstitial nephritis
Altered liver enzymes values
Blood urea increased
Blue-green discoloration of urine
Decrease in blood pressure
Impaired renal function
Increased uric acid level
Serum creatinine increased
Effects on Laboratory Tests
Triamterene interferes with the bioassay of folic acid.
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Last Full Review Date: April 2015.
Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.
Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.
Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press Accessed on 13 April 2015.
Martindale: The Complete Drug Reference (online) London: Brayfield A (ed). Pharmaceutical Press Accessed on 13 April 2015.
Medications and Mothers' Milk, Sixteenth Edition (2014) Hale, T and Rowe, H, Hale Publishing, Plano, Texas.
Summary of Product Characteristics: Triamterene 50mg capsules. Amdipharm Mercury Company Ltd. Revised May 2014.
The Renal Drug Handbook. Fourth Edition (2014) ed. Ashley, C and Dunleavy, A, Radcliffe Publishing Ltd, London.
US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
Available at: https://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT
Triamterene Last revised: 07 September 2013
Last accessed: 13 April 2015
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