- Abacavir
- Acarbose
- Acebutolol
- Acetaminophen
- Acetazolamide
- Acetohexamide
- Acetophenazine
- Acetylcholine
- Acetyldigitoxin
- Acitretin
- Acyclovir
- Adenosine
- Albendazole
- Albuterol
- Alfentanil
- Allopurinol
- Alphaprodine
- Alprazolam
- Alteplase
- Amantadine
- Ambenonium
- Amikacin
- Amiloride
- Aminocaproic Acid
- Aminoglutethimide
- Aminophylline
- Aminopterin
- Amiodarone
- Amitriptyline
- Amlodipine
- Ammonium Chloride
- Amobarbital
- Amoxapine
- Amoxicillin
- Amphetamine
- Amphotericin B
- Ampicillin
- Amprenavir
- Amrinone
- Amyl Nitrite
- Anagrelide
- Anileridine
- Anisindione
- Anisotropine
- Antazoline
- Antipyrine
- Aprobarbital
- Aprotinin
- Asparaginase
- Aspartame
- Aspirin
- Astemizole
- Atenolol
- Atorvastatin
- Atracurium
- Atropine
- Aurothioglucose
- Azatadine
- Azathioprine
- Azithromycin
- Aztreonam
