- Abacavir
- Abaloparatide
- Abamectin
- Abemaciclib
- Abietic Acid
- Abiraterone
- Abrocitinib
- Acalabrutinib
- Acamprosate
- Acarbose
- Acebrophylline
- Acebutolol
- Aceclofenac
- Acedoben
- Acemetacin
- Acenocoumarol
- Acesulfame Potassium
- Acetaminophen
- Acetazolamide
- Acetophenone
- Acetovanillone
- Acetylcysteine
- Acetylisovaleryltylosin
- Acetyltributyl Citrate
- Aciclovir
- Acitretin
- Aclonifen
- Acotiamide
- Acrivastine
- Adagrasib
- Adamantane
- Adapalene
- Adefovir
- Ademethionine
- Adenosine
- Adiphenine
- Adrenaline
- Adrenalone
- Afatinib
- Aflatoxin
- Afobazole
- Agomelatine
- Alarelin
- Albendazole
- Albuterol
- Alcaftadine
- Alclometasone Dipropionate
- Aldicarb
- Alectinib
- Alendronate
- Alfacalcidol
- Alfentanil
- Alfuzosin
- Algestone
- Alimemazine
- Allisartan Isoproxil
- Allopurinol
- Allylestrenol
- Almotriptan
- Alogliptin
- Alosetron
- Alpelisib
- Alprazolam
- Alprostadil
- Altizide
- Alverine
- Alvimopan
- Amantadine
- Ambrisentan
- Ambroxol
- Amfenac
- Amfepramone
- Amifampridine
- Amikacin
- Amiloride
- Aminocaproic acid
- Aminophylline
- Amiodarone
- Amisulpride
- Amitraz
- Amitriptyline
- Amlodipine
- Amodiaquine
- Amorolfine
- Amoxapine
- Amoxicillin
- Amphetamine
- Amphotericin B
- Ampicillin
- Amrubicin
- Amsacrine
- Amtolmetin Guacil
- Amylmetacresol
- Anagrelide
- Anastrozole
- Anhydrotetracycline
- Anidulafungin
- Anileridine
- Aniracetam
- Antipyrine
- Apalutamide
- Apixaban
- Apoatropine
- Apomorphine
- Apramycin
- Apremilast
- Aprepitant
- Aprindine
- Aprobarbital
- Arbutin
- Arformoterol
- Argatroban
- Arginine
- Aripiprazole
- Armodafinil
- Arotinolol
- Arteether
- Artemether
- Artemisinin
- Artesunate
- Asciminib
- Ascomycin
- Ascorbic Acid
- Asenapine
- Aspartame
- Aspartic Acid
- Aspirin
- Astemizole
- Atazanavir
- Atenolol
- Atipamezole
- Atomoxetine
- Atorvastatin
- Atosiban
- Atovaquone
- Atracurium
- Atrazine
- Atripla
- Atropine
- Avacopan
- Avanafil
- Avatrombopag
- Avermectin
- Avibactam
- Avilamycin
- Avobenzone
- Axitinib
- Azacitidine
- Azacyclonol
- Azafenidin
- Azatadine
- Azathioprine
- Azelaic acid
- Azelastine
- Azelnidipine
- Azilsartan
- Azilsartan Medoxomil
- Azithromycin
- Aztreonam
