Isoptin Retard
Isoptin retard is a calcium blocker that helps lower blood pressure, reduce heart rate, and correct irregular heart rhythms by relaxing blood vessels.
How to Use
Dosage
The typical dose is 120 mg to 240 mg, taken once or twice a day, as prescribed by your doctor.
Method
Swallow the extended-release tablets whole with plenty of liquid, preferably with or shortly after a meal. Do not chew or crush them. The 240 mg tablet can be split.
The maximum daily dose is usually up to 480 mg, divided into one or two doses.
Possible Side Effects
- •Headache
- •Nausea
- •Dizziness
- •Fatigue
- •Low blood pressure and slow heart rate
- •Impaired heart function
- •Hives (itchy rash)
- •Itchy skin
- •Facial redness and hot flashes
- •Swelling in limbs, such as ankles
- •Irregular heart rhythms
- •Heart palpitations or increased heart rate
- •Numbness or tingling sensation
- •Depression
- •Ringing in the ears (tinnitus)
- •Vomiting and stomach pain
- •Muscle cramps and weakness
- •Chest pain
- •Difficulty getting or keeping an erection
- •Increased liver enzyme levels (seen in blood tests)
- •Confusion and sleep problems
- •Cardiac arrest (heart stops)
- •Fainting spells
- •Small red spots on the skin (purpura)
- •Sensitivity to light
- •Severe skin reactions like erythema multiforme and Stevens-Johnson syndrome
- •Swelling of the face, lips, tongue, or throat (angioedema/Quincke's edema)
- •Breast enlargement, milk discharge, or increased prolactin levels
- •Muscle and joint pain
- •Gum overgrowth
- •Excessive sweating
- •Tremor (shaking)
- •High potassium levels (hyperkalemia)
- •Wheezing or shortness of breath (bronchospasm)
- •Kidney problems
- •Allergic reactions
- •Movement problems (extrapyramidal symptoms)
- •Seizures
- •Vertigo (spinning sensation)
- •Heart's natural pacemaker stopping (sinus arrest)
- •Rash
- •Hair loss
- •Bowel blockage or stomach issues
Important Warnings
- Do not use if you are allergic to verapamil or any other ingredient in this medicine.
- Do not use if you have very low blood pressure, severe heart shock (cardiogenic shock), certain irregular heart rhythms without a working pacemaker, severe heart failure, or certain atrial arrhythmias linked to an extra electrical pathway in the heart (WPW and LGL syndromes).
- Do not use if you are taking ivabradine (another heart medicine).
- Talk to your doctor before using this medicine if you have had a recent heart attack, heart failure, liver or kidney problems, slow heart rate (under 50 beats/min), very low blood pressure (systolic under 90 mmHg), or certain nerve-muscle conditions.
- Alcohol can make the medicine's effects stronger. Avoid alcohol, especially when you start treatment.
Show 2 more warnings
- This medicine can affect your ability to drive or use machines, especially at the start of treatment, when changing medication, or if you drink alcohol.
- This medicine is not recommended for children.
Use in Elderly Patients
Avoid use in older adults. Use only in special cases. Reduce the dose in moderately severe renal impairment. May exacerbate heart failure. Significant adverse effects include bradycardia, constipation, heart failure and swelling. Consider the numerous potential interactions. Avoid grapefruit. (updated 17.2.2025)