Carloc is carvedilol, a beta blocker supplied as 6.25 mg, 12.5 mg and 25 mg tablets. It is used for heart failure, high blood pressure and angina. In heart failure it does something unusual: it makes people feel slightly worse at first and considerably better over months.
What is Carloc?
Carloc contains carvedilol. The South African Medicine Price Registry lists three strengths, all Schedule 3:
| Product | Form | Strength |
|---|---|---|
| Carloc | Tablet | Carvedilol 6.25 mg |
| Carloc | Tablet | Carvedilol 12.5 mg |
| Carloc | Tablet | Carvedilol 25 mg |
Carvedilol is a beta blocker with additional alpha-blocking activity, which makes it broader than most of its class:
Beta blockade slows the heart, reduces how forcefully it contracts, and blunts the effect of adrenaline. That lowers the heart’s workload and its oxygen demand.
Alpha blockade relaxes and widens blood vessels, lowering the resistance the heart pumps against.
Together these do two useful things at once — a heart that works less hard, pumping into a system that resists less.
The three strengths exist because carvedilol is titrated. In heart failure especially, treatment starts at a low dose and doubles at intervals of about two weeks, provided it is tolerated, until the target is reached. That process can take months. A rising dose means the plan is working, not that the heart is failing faster — a point worth knowing, because the opposite assumption causes people to stop.
What is Carloc commonly used for?
- Chronic heart failure, with reduced ejection fraction. This is its most important use. Alongside an ACE inhibitor or ARB, carvedilol is one of the treatments shown to reduce hospital admissions and prolong survival, not merely to control symptoms.
- High blood pressure, alone or with other medicines.
- Angina — reducing the frequency of chest pain by lowering the heart’s oxygen demand.
- After a heart attack, protecting heart function.
- Some heart rhythm problems, and in cirrhosis to reduce portal pressure, under specialist care.
The heart failure use is worth explaining, because it is counter-intuitive. In heart failure the body compensates by driving the heart harder with adrenaline. That works briefly and damages the heart over time. Beta blockers stop that driving — and in the first weeks people may feel more tired, more breathless, or notice more ankle swelling as the heart adjusts to running less hard.
That early phase is expected. Pushed through, with dose adjustments as needed, carvedilol improves how the heart works over the following months. Stopping because the first fortnight feels worse is the most common way this treatment is lost.
How Carloc fits into this medicine category
| Group | Examples | How it works |
|---|---|---|
| Beta blockers | Carvedilol (Carloc), bisoprolol, atenolol, metoprolol | Slow the heart, reduce its workload |
| ACE inhibitors | Enalapril, perindopril | Block a hormone that narrows vessels |
| ARBs | Losartan, telmisartan | Similar, without the cough |
| Calcium channel blockers | Amlodipine (Ciplavasc) | Relax arteries |
| Diuretics | Hydrochlorothiazide (Ridaq), furosemide | Remove salt and fluid |
| Mineralocorticoid blockers | Spironolactone | Added in heart failure |
Not all beta blockers are equivalent in heart failure — carvedilol, bisoprolol and metoprolol succinate have the evidence, which is why a switch between beta blockers is a deliberate decision rather than a substitution. See the heart and blood pressure medicines hub.
What to check before using Carloc
Never stop a beta blocker suddenly. Abrupt withdrawal can cause a rebound surge in heart rate and blood pressure, worsening angina and, in people with coronary disease, precipitating a heart attack. Any reduction must be gradual and planned.
Tell your doctor or pharmacist if you:
- Have asthma or significant COPD. Beta blockers can cause bronchospasm; carvedilol is generally avoided in asthma.
- Have a slow heart rate, heart block, or a pacemaker question.
- Have decompensated heart failure — carvedilol is started when someone is stable, not during an acute episode.
- Have diabetes. Beta blockers can mask the warning signs of low blood sugar, particularly the tremor and palpitations. Sweating usually remains. Monitor more closely at first.
- Have liver disease, or peripheral arterial disease with cold hands and feet.
- Have phaeochromocytoma, or a history of severe allergic reactions — beta blockers can make adrenaline less effective in anaphylaxis.
- Take verapamil or diltiazem, digoxin, amiodarone, insulin or diabetes tablets, anti-inflammatories, or clonidine.
- Wear contact lenses, or are due for surgery — tell the anaesthetist.
- Are pregnant or breastfeeding.
Practical points:
- Take it with food. This slows absorption and reduces dizziness.
- Take it at the same times daily, usually twice.
- Get up slowly from sitting or lying, especially after a dose increase.
- Weigh yourself regularly if you have heart failure, and report a rapid gain — a sudden increase usually means fluid, not fat.
- Do not stop it because you feel tired in the first weeks. Speak to your doctor instead.
Possible cautions and when to ask a pharmacist or doctor
Common effects are dizziness, tiredness, low blood pressure, slow heart rate, headache, cold hands and feet, and shortness of breath. Most are dose-related and improve as the body adjusts.
Get emergency help for:
- Fainting, or a very slow or irregular heartbeat.
- Severe breathlessness, especially lying flat or waking you at night.
- Wheezing or an asthma attack.
- Chest pain.
- Rapid weight gain with swelling of the legs or abdomen — worsening heart failure.
- Swelling of the face, lips or tongue, difficulty breathing, or a blistering rash.
Contact your doctor if:
- You feel more tired or breathless after starting or after a dose increase. The dose can often be adjusted or the increase delayed — this is a conversation, not a reason to stop.
- Dizziness is interfering with daily life.
- Your pulse feels persistently slow, or you notice palpitations.
- You have diabetes and are unsure about recognising low blood sugar.
- You are running low on tablets. Do not let them run out.
Related medicine guides
Frequently asked questions
What are Carloc tablets used for? Chronic heart failure, high blood pressure, angina and protection after a heart attack. It contains carvedilol.
What is Carloc 25 used for? The same conditions — 25 mg is the higher strength, usually reached after gradual dose increases.
Why does my dose keep going up? Carvedilol is deliberately titrated upwards over weeks to a target dose. A rising dose reflects the plan, not deterioration.
Why do I feel worse since starting it? In heart failure, feeling more tired or breathless in the first weeks is expected as the heart adjusts. It usually improves. Tell your doctor rather than stopping.
Can I stop it if I feel fine? No. Stopping suddenly can cause a rebound rise in heart rate and blood pressure and can trigger angina or a heart attack. Any change must be planned.
Can I take it with asthma? Usually not. Beta blockers can trigger bronchospasm, and carvedilol is generally avoided in asthma. Tell your doctor.
Should I take it with food? Yes. Food slows absorption and reduces dizziness.
Will it mask low blood sugar? It can mask the tremor and palpitations of hypoglycaemia, though sweating usually remains. Monitor more closely if you have diabetes.