Ticagrelor

Is ticagrelor safe?

For people who have had a heart attack or unstable angina, ticagrelor usually does more good than harm, and in its main trial it saved lives compared with the older drug clopidogrel. The price is bleeding, which the US label puts in a boxed warningBoxed warningThe strongest safety warning the US FDA puts on a medicine's label, printed inside a black border at the top.More in the glossary, and a side effect most patients have never heard of: breathlessness. About one person in seven feels it.

We score ticagrelor 67. That is below clopidogrel (72), mainly because it causes more bleeding and has more interactions, but above the anticoagulants apixaban (64) and warfarin (49). The score describes the drug's risks, not whether you should take it. Stopping it early after a stent is one of the more dangerous things a heart patient can do.

How it compares with clopidogrel

Both drugs block the P2Y12 receptor on platelets, but in different ways. Clopidogrel is a prodrug that the liver must activate through CYP2C19CYP450 enzymesA family of liver enzymes that break down many medicines. When another drug or supplement speeds them up or slows them down, drug levels change.More in the glossary, so it works poorly in people with two inactive copies of that gene. Ticagrelor works directly, binds reversibly and acts within hours. It is taken twice a day, and its effect fades faster when stopped.

The PLATO trial compared the two in 18,624 people with acute coronary syndromes, almost all also taking aspirin. The US label gives the results per 1,000 patient-years:

So ticagrelor prevented more heart deaths than it caused bleeding deaths. More people stopped it because of side effects, though: 7.4% against 5.4% on clopidogrel, according to the UK label.

Bleeding

Any drug that stops platelets working raises the risk of bleeding, from nosebleeds and bruising to bleeding in the gut or brain. The US label rules ticagrelor out for anyone with active bleeding, such as a stomach ulcer, or a past bleed inside the skull. About half of the major bleeds in PLATO happened in the first 30 days.

After a year, the label drops the dose to 60 mg twice a day, which carries less bleeding risk. In the PEGASUS trial of people with an older heart attack, that dose still nearly tripled TIMI major bleeding compared with aspirin alone (8 vs 3 events per 1,000 patient-years). For people who have had a stent, the current US label says doctors can consider dropping aspirin and using ticagrelor alone, depending on the balance of clot and bleeding risk.

There is no antidote on the label. Ticagrelor cannot be removed by dialysis, and the US label says platelet transfusion did not reverse it in healthy volunteers. An experimental antibody, bentracimab, has been tested for urgent reversal and filed with the FDA, but Drugs@FDA lists no approval as of October 2026 and neither the US nor the UK label names it.

Breathlessness and heart rhythm

The breathlessness can be alarming in someone who has just had a heart attack. The labels describe it as usually mild to moderate and often fading while treatment continues; lung function tests in a PLATO substudy showed no harm. People with asthma or COPD are more likely to notice it. Only 0.9% stopped ticagrelor for this reason in PLATO, though more did in later trials of long-term use.

Ticagrelor can also cause pauses in the heartbeat. In a PLATO heart-monitor substudy, 6.0% had ventricular pauses early in treatment against 3.5% on clopidogrel, falling to 2.2% and 1.6% after a month. People with sick sinus syndrome or heart block without a pacemaker were excluded from the trials. Other effects on the labels include raised uric acid and gout, and central sleep apnoea.

Interactions

Ticagrelor is cleared by the liver enzyme CYP3A4CYP450 enzymesA family of liver enzymes that break down many medicines. When another drug or supplement speeds them up or slows them down, drug levels change.More in the glossary, which makes its interactions different from clopidogrel's:

• Strong CYP3A blockers such as clarithromycin, ketoconazole, itraconazole and ritonavir raise ticagrelor levels sharply and should be avoided.
• Strong CYP3A inducers such as rifampin, carbamazepine, phenytoin and phenobarbital can stop it working.
• Statins: keep simvastatin and lovastatin at 40 mg or less. It also raises rosuvastatin levels.
• Aspirin above 100 mg a day made ticagrelor less effective in PLATO.
• Opioids such as morphine delay its absorption, which matters during an emergency heart attack.
• Digoxin levels should be checked when ticagrelor is started or changed.
• Other blood thinners, NSAIDs and SSRI antidepressants add to bleeding risk.

Large daily amounts of grapefruit juice doubled ticagrelor levels in a study, which the UK label does not expect to matter for most people.

Who should be careful

Talk to your doctor or pharmacist before starting ticagrelor, or adding anything to it, if you:

• have had a stomach ulcer, bleeding in the gut or a bleed in the brain
• have asthma, COPD, a slow heart rate or heart block without a pacemaker
• have severe liver disease (the UK label rules it out)
• take an anticoagulant, an NSAID, an antibiotic or antifungal, or an HIV medicine
• are booked for surgery or dental work

Tell every doctor and dentist that you take it. Get urgent help for black or bloody stools, vomiting blood, or bleeding that will not stop. In an overdose, call Poison Help on 1-800-222-1222 in the US or NHS 111 in the UK.

How we scored it

Dependence (98) and track record (85) are strong, and single overdoses are well tolerated (70), though the lack of an antidote holds that factor back. Serious side effects (58) reflect more bleeding than clopidogrel plus breathlessness and heart pauses, interactions (50) the CYP3A4CYP450 enzymesA family of liver enzymes that break down many medicines. When another drug or supplement speeds them up or slows them down, drug levels change.More in the glossary, statin and aspirin rules, and the bleeding boxed warningBoxed warningThe strongest safety warning the US FDA puts on a medicine's label, printed inside a black border at the top.More in the glossary keeps regulatory warnings at 45.