Any of the pairs of nucleotides connecting the complementary strands of a molecule of DNA or RNA and consisting of a purine linked to a pyrimidine by hydrogen bonds. The base pairs are adenine-thymine and guanine-cytosine in DNA, and adenine-uracil and guanine-cytosine in RNA or in hybrid DNA-RNA pairing. Base pairs may be thought of as the rungs of the DNA ladder.
Drugs used to prevent migraines include: 1  Anticonvulsants, such as topiramate. 2  AntidepressantsAntidepressants, such as amitriptyline. 3  Antihistamine , such as cyproheptadine.  Beta-blockers, such as 1  propranolol. Botulinum toxinBotulinum toxin, such as Botox.  Calcium channel blockers, such as 1  verapamil. Histamine.
Other antidepressants used to prevent tension headaches include mirtazapine (Remeron) and venlafaxine (Effexor). The U.S. Food and Drug Administration (FDA) has issued an advisory on antidepressant medicines and the risk of suicide. Talk to your doctor about these possible side effects and the warning signs of suicide.