Meds and you

27 September 2013

The combination of hydrochlorothiazide and potassium

Hydrochlorothiazide is a diuretic drug, which means that it increases the flow of urine from the body. Potassium is an electrolyte which are chemicals such as salts and minerals.


The combination of hydrochlorothiazide and potassium is the active ingredient of Urirex K (Nappi code: 774057-009).

General information
Hydrochlorothiazide is a diuretic drug, which means that it increases the flow of urine from the body. It is used to treat both congestive heart failure, a condition where the heart battles to cope with its workload, and mild to moderately high blood pressure.

Potassium is an electrolyte, which are chemicals such as salts and minerals needed for various functions in the body.

This combination is not a cure for high blood pressure, but is effective in keeping it under control. For it to be effective, you must take it regularly. High blood pressure declines slowly and it may take a few weeks for this medication to have its full effect. Keep taking this medicine during this period, even if you are feeling better, or fail to notice any improvement.

The first couple of doses of this medication may cause a sudden drop in blood pressure, which may cause dizziness or blackouts when you suddenly get up. It is therefore advised that you rest when starting treatment and to lie down for 2 hours afterwards.

This combination is also indicated for the treatment of oedema (an accumulation of excessive amounts of fluid in body tissue resulting in swelling) that results from conditions such as congestive heart failure, kidney disorders and premenstrual syndrome.

The combination of hydrochlorothiazide and potassium should best be taken in the morning to prevent additional night-time visits to the toilet. It is possible that you may produce a larger volume of urine at the start of treatment with this medication. Be aware of where your nearest ablution facilities are if you are away from home.

How does this combination work?
A diuretic such as hydrochlorothiazide reduces the overall fluid volume in the body, thereby reducing pressure within blood vessels, while helping to control the body's fluid balance that may result from the use of hydrochlorothiazide.

Fast facts

Drug schedule: schedule 3
Available as: the combination of hydrochlorothiazide and potassium is available as tablets.
What does it do? This medication lowers blood pressure and reduces fluid volume in the body.
Overdose risk: low
Dependence risk: low
Is the combination of hydrochlorothiazide and potassium available as a generic? yes
Is combination of hydrochlorothiazide and potassium available on prescription only? yes

User information

Onset of effect: within 2 hours
Duration of action: up to 12 hours
Dietary advice: this combination should best be taken with or after a meal, and with plenty of water.
Stopping this medicine: it may be dangerous to discontinue this drug abruptly as symptoms of the condition being treated may recur. Don't discontinue this drug without speaking to your doctor.
Prolonged use: prolonged use may result in an electrolyte disturbance. Kidney function may also need to be evaluated periodically.

Special precautions
Consult your doctor before using this drug if:

  • you have kidney or liver disease
  • you are taking ACE-inhibitor drugs
  • you have gout
  • you have a stomach ulcer
  • you are dehydrated
  • you have diabetes
  • you have Addison's disease
  • you have systemic lupus erythematosus
  • you are taking other medication

Pregnancy: avoid. Potential risk to the foetus has been reported. Consult your doctor before use, or if you are planning to fall pregnant.
Breastfeeding: avoid. This medication is passed through breast milk and may affect your baby adversely. Consult your doctor before use.
Porphyria: this medication is safe for use.
Infants and children: if used in children, the dose must be determined by a paediatrician.
The elderly: caution is advised in the elderly as adverse effects may be more likely.
Driving and hazardous work: caution is advised as use of this medication may lead to dizziness and light-headedness. Avoid such activities until you know how this medication affects you.
Alcohol: avoid concomitant use of alcohol with this medication.

Possible side effects


Side Effect
Consult your doctor
Only if severe
In all cases
muscle cramps or pain
thirst/dry mouth
loss of appetite
erectile dysfunction
increased blood sugar
skin rash/itch
swelling of mouth/difficulty breathing
unusual bleeding and bruising


Drug interactions


ACE inhibitor drugs increased dizziness at start of treatment/ increased risk of potassium toxicity
alcohol, barbiturates increased dizziness at start of treatment
allopurinol, tetracycline antibiotics increased risk of hydrochlorothiazide toxicity
cholestyramine reduced absorption of hydrochlorothiazide
corticosteroids reduced diuretic effect/ risk of potassium depletion
digoxin increased risk of toxicity in case of potassium depletion
terfenadine, sotalol, pimozide risk of heart rhythm disturbance
lithium risk of lithium toxicity
non-steroidal anti-inflammatory drugs reduced diuretic effect/ increased risk of kidney damage
oral anti-diabetic drugs blood-sugar lowering effect may be reduced
co-trimoxazole, trimethoprim reduced sodium levels in body
vitamin D increased risk of high calcium blood levels
potassium sparing diuretics including amiloride, triamterene and spirinolactone risk of potassium toxicity

Disease interactions
Consult your doctor before using this drug if you have kidney or liver disease, gout, a stomach ulcer, diabetes, Addison’s disease, or if you have systemic lupus erythematosus.

Overdose action
A small overdose is no cause for concern. In case of intentional large overdose, seek emergency medical attention.

Recommended dosage
Adults: ½ to 2 tablets in the morning or on alternate mornings.


This material is not intended to substitute medical advice, but is for informational purposes only. Please consult a physician for specific treatment and recommendations.



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