Why beta blockers are contraindicated in vasospastic angina?

Beta blockers are contraindicated in vasospastic angina because they can potentially exacerbate vasospasm. These medications decrease heart rate and contractility, which can lead to unopposed alpha-adrenergic receptor stimulation in the coronary arteries, causing them to constrict further. This can worsen ischemia and provoke anginal episodes. Instead, calcium channel blockers or long-acting nitrates are typically preferred to help relieve vascular tension and prevent spasms.