What condition is amantadine used to treat that is caused by antipsychotics?

Amantadine is primarily indicated for the treatment of drug-induced parkinsonism, a condition that can arise as a side effect of antipsychotic medications. Antipsychotics, especially those that are dopamine antagonists, can lead to a deficiency in dopamine neurotransmission, resulting in symptoms similar to Parkinson's disease. These symptoms may include rigidity, bradykinesia, and tremors.

Amantadine works by increasing dopamine release and blocking the reuptake of dopamine in the brain, which helps alleviate these symptoms. Its use in managing drug-induced parkinsonism is particularly valuable for treating patients who are experiencing these side effects without having to reduce their antipsychotic therapy, thereby balancing the need for psychosis management with the need to address movement disorder symptoms.

The other conditions listed are not treatable with amantadine in the context of drug-induced parkinsonism: Alzheimer's disease is a neurodegenerative condition primarily affecting cognition; multiple sclerosis is an autoimmune disease affecting the central nervous system that typically requires different immunomodulating therapies; and myasthenia gravis is an autoimmune neuromuscular disorder that is treated with anticholinesterase inhibitors and immunosuppressants, not amantadine.