By Fatma Younis
As Halloween approaches, health experts are warning that certain seasonal sweets can interfere with common medications or worsen existing health conditions. Ingredients in chocolate, liquorice, and sugar-free candies may reduce drug effectiveness or trigger harmful side effects, according to pharmacology guidance.
Chocolate and MAOI antidepressants
Chocolate contains tyramine, a substance that can build up to dangerous levels in people taking monoamine oxidase inhibitors (MAOIs), an older class of antidepressant. This buildup can cause a sudden, severe spike in blood pressure, a medical emergency that can be fatal if untreated. Dark chocolate poses a higher risk due to greater tyramine content, while milk chocolate contains less. Doctors generally advise caution or avoidance, especially during early treatment stages or at higher doses.
Caffeine interactions with ADHD and heart drugs
Chocolate also contains caffeine, a stimulant that can intensify the effects of ADHD medications such as methylphenidate (Ritalin), leading to jitteriness, insomnia, and rapid heartbeat. Caffeine may also reduce the calming effects of antidepressants and anti-anxiety drugs like SSRIs, and can raise blood pressure and heart rate, complicating treatment for people on beta-blockers. A 50-gram bar of dark chocolate typically contains under 25 milligrams of caffeine, but combined with coffee or energy drinks, total intake can exceed recommended limits, particularly for pregnant individuals.
Liquorice risks for blood pressure and kidney patients
Black liquorice contains glycyrrhizin, which mimics the hormone aldosterone, causing sodium retention, potassium loss, fluid retention, and increased blood pressure. Even small amounts — around 100 milligrams of glycyrrhizic acid daily — can raise blood pressure, matching the World Health Organization's upper limit. These effects are especially dangerous for people taking diuretics, antiarrhythmic drugs, or blood pressure medication, and for those with kidney disease. Liquorice-flavoured sweets without real liquorice are generally safe.
Artificial sweeteners and genetic disorder risk
Sugar-free sweets often contain aspartame, which breaks down into phenylalanine. This can be toxic for people with phenylketonuria (PKU), a rare genetic disorder that prevents proper metabolism of phenylalanine, leading to brain cell damage. Individuals with PKU should avoid aspartame-containing products.
