People who are prescribed a widely used medication are being advised to contact a doctor if they notice certain symptoms. As per Mirror, health officials say these “serious” side effects should not be delayed or ignored and may need medical review sooner rather than later. Diltiazem is a drug commonly given to manage high blood pressure. It is also sold under brand names such as Adizem, Angitil, Tildiem, Viazem, and Zemtard. Doctors prescribe it to people with high blood pressure to lower the risk of coronary heart disease, heart attacks, and strokes. The medicine helps by reducing blood pressure and allowing the heart to pump blood more easily through the body. However, new warnings linked to the drug have now been highlighted.What Is Diltiazem?Diltiazem belongs to a group of medicines called calcium channel blockers. It is used to treat high blood pressure, long-term stable angina, which causes chest pain, and certain types of irregular heartbeats. The drug works by relaxing blood vessels and easing the strain on the heart. According to Medline Plus, common side effects may include dizziness, headaches, swelling, and a slower heart rate. It is mainly prescribed for hypertension, angina, and heart rhythm conditions such as atrial fibrillation. In some cases, it is also used in cream form to help treat anal fissures.The NHS website also states that diltiazem may be used to:Prevent chest pain linked to anginaLower the number of attacks in people with Raynaud’s phenomenonSupport the healing of an anal fissureLike most medicines, diltiazem can cause side effects, although many people may not experience any. The NHS notes that there are several “common” side effects patients should be aware of.Diltiazem Common Side EffectsThese effects are seen in more than one in 100 people. The NHS explains: “They are usually mild and do not last long. There are ways to help manage them.”They include:Swelling in the hands, ankles, or feetHeadachesDizziness or feeling light-headedFeeling tired, weak, or generally unwellFeeling hot, flushed, or noticing redness of the skinItching or a burning feeling on the skin where the cream or ointment is appliedStomach discomfortIndigestionConstipationThe NHS adds: “Talk to a doctor or pharmacist if coping advice does not help, or if a side effect continues or becomes troublesome.”Diltiazem Serious Side EffectsIn rare cases, diltiazem may lead to “serious side effects.” These are reported in fewer than one in 10,000 people.According to the NHS, you should “stop taking diltiazem and contact a doctor or call 111 immediately” if:You experience severe stomach painThe whites of your eyes or your skin turn yellow, which may be harder to notice on brown or black skin and could point to liver problemsYou become aware of your heartbeat or notice palpitationsYou should also call 999 or go straight to A&E if you have chest pain that does not ease after a few minutes, or if chest pain is new or worse than usual when you already have angina. This may indicate a heart attack and requires urgent medical attention.