Some disadvantages of antibiotics include ineffectiveness against viruses, potential drug interactions, frequent misuse, overuse and potential side effects. Additionally, widespread use of antibiotics can cause bacteria to evolve into antibiotic-resistant strains.
Antibiotic resistance is a bacteria's ability to withstand high doses of antibiotics and pass that ability on to later generations. Additionally, antibiotic-resistant bacteria can transfer their immunity, through plasmids, to other strains and species of bacteria. Superbugs are bacteria that no longer respond to antibiotic treatment. Multi-drug-resistant tuberculosis, or MDR-TB, is a superbug that causes 1/2 million new cases each year, as of 2014.
Antibiotics sometimes cause drug interactions that make a medication ineffective, cause side effects or cause damage to a patient's biological systems. Mixing alcohol with antibiotics may decrease their effectiveness or cause nausea, vomiting and respiratory effects. Antibiotics sometimes make birth control pills ineffective. Rifampicin is suspected to have this effect because of the liver's accelerated breakdown of the pill's active ingredients. Combining quinolone and corticosteroids can cause tendon damage.
Misuse and overuse are two common problems. In the past, doctors prescribed antibiotics before determining whether an infection was bacterial or viral. Farmers and veterinarians still use prophylactic antibiotics in livestock that promote the evolution of superbugs. Patients also often fail to take antibiotics exactly as prescribed, allowing resistant strains to develop.
Antibiotics can cause side effects, such as fever, diarrhea, nausea, allergic reactions and physiological imbalances, which lead to secondary infections.