Every pharmaceutical drug can cause an adverse reaction, but sometimes the effects are so significant---or the drug just doesn't do what it is supposed to---that the risks far outweigh any benefits. Here's a list of some of those drugs.
ADHD drugs. Many parents watch with relief as their ADHD (attention-deficit/hyperactivity disorder) child takes a drug such as Ritalin and his behavior improves almost immediately. However, this usually means that the child then takes the drug for the remainder of his adolescence and possibly even into early adulthood. Yet, one study has discovered that the drugs have a beneficial effect only for the first 14 months; thereafter, any improvement is down to natural causes. The researchers tracked two groups of ADHD children: one group was taking a drug such as Ritalin, Adderall or Concerta, and the other group had never taken a drug. After 14 months, the non-drug group suddenly displayed marked improvement, while the drug group maintained the same level of inattention and hyperactivity (J Am Acad Child Adolesc Psychiatry, 2009; 48: 240--8).
Alzheimer's drugs. A family of drugs known as 'cholinesterase inhibitors' are commonly prescribed for dementia and Alzheimer's disease. However, several studies have questioned their effectiveness in slowing cognitive disorders, and a later study from the Institute for Clinical Evaluative Sciences in Toronto discovered that they also cause a range of serious side effects. These drugs---Aricept (donepezil), Exelon (rivastigmine) and Razadyne (galantamine)---increase the risk of fainting, bradycardia (slowing of the heart rate to dangerously low levels) and hip fracture. Patients may also need a pacemaker as a direct result of taking one of these drugs (Arch Intern Med, 2009; 169: 867--73).
Antibiotics. Although antibiotics have been lifesavers, they are so overprescribed---and often inappropriately for viral conditions--- that they are now considered to be one of the most dangerous families of drugs around today. About 20 per cent of all drug-related visits to accident and emergency units are due to an antibiotic. Over a two-year period, 142,000 Americans reacted so badly to an antibiotic that they had to be admitted to hospital (Clin Infect Dis, 2008; 47: 735--43). The drugs can also make bacterial infections worse. In a study of 119 children, 71 were given amoxicillin, a moderate spectrum penicillin. Within two weeks, many of the children had developed antibiotic-resistant bacteria (BMJ, 2007; 335: 429).
Antidepressants. People with clinical depression are not helped by antidepressants. The new generation of drugs is not targeted at the cause of most depression---a brain protein called 'monoamine oxidase A' (MAO-A)---and time is the best healer, say researchers at the Centre for Addiction and Mental Health in Toronto (Arch Gen Psychiatry, 2009; 66: 1304--12). Not only are they ineffective, but they also dramatically increase the risk of suicide. The worst culprit was Effexor (venlafaxine), one study discovered (BMJ, 2007; 334: 242). Antidepressants also increase your chances of stroke and of death by any cause if you are a postmenopausal woman (Arch Intern Med, 2009; 169: 2128--39).
Aspirin. Around 100 billion aspirin pills are taken every year, usually as part of a health regime to ward off heart disease. Although it's recognized that the NSAID (non-steroidal anti-inflammatory drug) causes gastrointestinal (GI) bleeding, the extent---and severity---has only recently come to light. Researchers now reckon that the drug is killing around 20,000 Americans and sending another 100,000 to hospital every year.
Worldwide, aspirin is killing around 100,000 every year due to GI reactions (Proceedings of the Annual Scientific Meeting of the American College of Gastroenterology, 15 October, 2007). It also increases the risk of stroke in the over-75s, according to a study that looked at population clusters during 1981--1986 and 2002--2006 (Lancet Neurol, 2007; 6: 487--93).
Proton pump inhibitors (PPIs). Around 2 billion ($2.86 billion) is spent each year around the world on these indigestion drugs. Studies reveal that they don't work, and that most people who take them don't need them in the first place. PPIs stop the backflow of stomach acid, thus stopping heartburn. If they don't work, the view is that they won't harm you, but this is also not the case. They can cause stomach infections, and can double the risk of Clostridium difficile infection (JAMA, 2005; 294: 2989--95).
This is because PPIs block the production of gastric acid, the body's natural defense against harmful bacteria. The drugs can also increase the risk of pneumonia (Arch Intern Med, 2007; 167: 950--5) and hip fracture (JAMA, 2006; 296: 2947--53).
Statins. These cholesterol-lowering drugs are among the most popular drugs on the market. Around 36 million Americans take one every day, and annual sales revenues total $15.5 billion. Two statins---Lipitor and Zocor---are the two best-selling drugs in the US. Although there is evidence that people with an existing heart condition derive benefit from the drugs, which accounts for only 8 per cent of users. The rest are taking the drug as a just-in-case remedy, but the evidence doesn't suggest that the drugs are doing any good for healthy people. Harvard researchers analyzed eight studies and concluded that statins don't save lives--- and even their benefits for heart patients are marginal. Worse, the drugs can have a paradoxical effect, causing the very heart conditions they are supposed to protect against. They have also been cited as a cause of Parkinson's disease (Lancet, 2007; 369:268--9).
The person who takes medicine must recover twice, once from the disease and once from the medicine." William Osler, M.D