- Abacavir
- Abemaciclib
- Abietic Acid
- Abiraterone Acetate
- Acarbose
- Acebutolol
- Acenocoumarol
- Acetaldehyde
- Acetamide
- Acetonitrile
- Acetophenone
- Acetylcysteine
- Acotiamide
- Acrivastine
- Acyclovir
- Adamantane
- Adapalene
- Adefovir
- Ademethionine
- Adenosine
- Adrenaline
- Aflatoxin
- Agomelatine
- Alanine
- Albendazole
- Albuterol
- Alectinib
- Alfuzosin
- Allopurinol
- Almotriptan
- Alpelisib
- Ambrisentan
- Amikacin
- Amiloride
- Aminocaproic Acid
- Aminolevulinicacid
- Aminophenyl
- Amiodarone
- Amisulpride
- Amlodipine
- Amodiaquine
- Amorolfine
- Amoxapine
- Amoxicillin
- Amphetamine
- Amphotericin B
- Ampicillin
- Amrubicin
- Amsacrine
- Anagrelide
- Aniline
- Anthracene
- Anthraquinone
- Apixaban
- Apremilast
- Argatroban
- Arginine
- Aripiprazole
- Artemether
- Artemisinin
- Ascorbic Acid
- Aspirin
- Atazanavir
- Atenolol
- Atorvastatin
- Atovaquone
- Atracurium
- Atrazine
- Atropine
- Avanafil
- Avermectin
- Azelastine
- Azelnidipine
- Azetidine