Meds and you

Updated 11 February 2013

Isradipine

Isradipine is a medication that widens and relaxes blood vessels, and decrease the rate at which the heart beats.

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Isradipine is the active ingredient of Dynacirc.

General information

Isradipine is a medication that widens and relaxes blood vessels, and decrease the rate at which the heart beats.

It is used for the treatment of high blood pressure.

Isradipine does not cure this condition, but keeps it under control. For isradipine to be effective it has to be taken regularly, even if you do not notice any immediate effect - it may take several weeks no notice the full benefit of this medication.

Be aware that, at the start of treatment with this medication, you may feel dizzy, especially when getting up suddenly. Caution is advised.

How does isradipine work?

Calcium plays an important role in the contraction of heart muscle, and the smooth muscle in the walls of arteries. Blocking the channels though which calcium enters cells in these muscles, prompts them to relax. The result is a reduced workload for the heart, as well as widening of blood vessels, causing high blood pressure to return to normal and safe levels.

Fast facts

Drug schedule: Schedule 3

Available as: Tablets and capsules

What does it do? Isradipine reduces high blood pressure

Overdose risk: Medium

Dependence risk: Low

Available as a generic? No

Available on prescription only? Yes

User information

Onset of effect: Within 2 hours.

Duration of action: Up to 12 hours.

Dietary advice: To minimise stomach irritation and adverse effects, this medication should be taken with or immediately after food; a low-salt, low-fat diet is advised.

Stopping: Consult you prescriber before discontinuing treatment - abrupt withdrawal of medication may cause a return of symptoms.

Prolonged use: Although no problem is expected with long-term use, your doctor may occasionally request kidney and liver function tests.

Special precautions

Alert your doctor before using this drug if:

  • you have a liver or kidney disease,
  • you have or have had congestive heart failure,
  • you have unstable angina, or
  • 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: Avoid. This medication may cause serious adverse effects. Consult your doctor before use.

Infants and children: Safety and efficacy of this medication has not been established for children under the age of 12.

Elderly: Caution is advised in the elderly, as dosage adjustment may be needed.

Driving and hazardous work : Caution is advised as use of this medication may lead to dizziness, light-headedness and/or sedation. Avoid such activities until you know how it affects you.

Alcohol: Avoid concomitant use of alcohol with this medication, as it is possible that the combination may cause a further drop in blood pressure, adding to dizziness. Caution is advised.

Possible side effects

Side effect

Frequency

Consult your doctor

Common

Rare

Only if severe

In all cases

Headache

x

x

Dizziness/ light-headedness

x

x

Flushing in face

x

x

Urine retention

x

x

Swelling/ weight gain

x

x

Fatigue

x

x

Drowsiness

x

x

Nausea/ abdominal pain

x

x

Palpitations

x

x

Rash

x

x

Low blood pressure

x

x

Shortness of breath

x

x

Increase in angina attacks

x

x

Interactions

Drug interactions

ACE inhibitor drugs

Possible decrease in blood pressure

Some antifungal drugs

Increased risk of isradipine toxicity

Beta blocking drugs

Increased risk of heart failure

Cimetidine

Increased risk of isradipine toxicity

Digoxin

Increased risk of digoxin toxicity

Rifampicin

Reduced effect of isradipine

Ritonavir

Increased risk of Isradipine toxicity

Theophylline

Increased risk of theophylline toxicity

Food interactions

A low-salt, low-fat diet is advised. Alcohol may cause a drop in blood pressure.

Disease interactions

Consult your doctor before using this drug if you have a liver or kidney disease, congestive heart failure, or if you have unstable angina.

Overdose action

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

Recommended dosage

Adults, oral: 2.5-5mg once a day, usually in the morning. A lower dose (1.25mg) may be needed for the elderly.

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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