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The scariest and strangest side effects of medications
Last reviewed: 01.07.2025

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Medicines often act on the human body not only for their intended purpose.
Most medications have side effects that can sometimes be very serious and even strange. Web2Health presents the strangest and scariest side effects of various medications.
Amnesia
Surely you can remember at least one movie, the plot of which revolves around a person who, for example, after a car accident, lost his memory and does not even remember his name. This condition is called amnesia, and it can be caused not only by head injuries, but also by drugs such as Mirapex (prescribed to people suffering from Parkinson's disease) and Lipitor (lowers cholesterol). Due to short-term memory loss, patients who take these drugs may sometimes not know where they were yesterday.
Loss of feelings
The drug Vasotec is intended to normalize blood pressure. In some people, it can cause a disorder of almost all five senses. Due to the side effects of the drug, people can temporarily lose their sense of smell and taste, and multi-colored circles can float before their eyes.
Colored urine
Phenazopyridine, which is used to treat urinary tract infections, deferoxamine, which is used to treat iron poisoning, and a number of other drugs can turn a patient's urine black, purple, green, or blue.
Hallucinations
Not only LSD can cause hallucinations, but also a number of other drugs that are not common drugs. A side effect of taking Mirapex can be not only amnesia, but also strong hallucinations, which, for example, make patients hide in the toilet from snakes invisible to others.
Lariam, a remedy for malaria, also has a hallucinogenic effect.
Nightmares
Chantix is designed to stop a smoker from smoking, but it can also stop them from sleeping. The drug can cause nightmares that cause patients to wake up screaming in terror.
Encopresis (fecal incontinence)
Various drugs for "fast and effective" weight loss can be very dangerous. For example, breaking the diet while taking Xenical can lead to loss of the ability to control the act of defecation. With such a violation, the patient defecates more often than usual and is unable to hold back.
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Compulsive behavior
After taking the same Mirapex, many patients began to experience behavioral problems that they had not had before. Those who drank only on holidays and in small amounts became alcoholics, others began to experience an excessive passion for gambling, shopping or sex.
Suicidal mood
The antimalarial Lariam and the antidepressant Paxil can drive a person to suicide. Some patients taking Lariam have suicidal thoughts that can develop into actions. Doctors also suspect that Chantix has this side effect.
Developmental defects
Taking certain medications by a pregnant woman can cause serious birth defects in her baby. In the late 1950s and early 1960s, about ten thousand babies were born with birth defects in several countries around the world.
Read also: "The Thalidomide Tragedy": An Apology Half a Century Later
Their mothers took the sleeping pill Thalidomide during pregnancy.