cGMP: nootropics and compounds | sci-wiki

Acetildenafil

Acetildenafil, also known as hongdenafil, is a designer analogue of sildenafil (Viagra) and one of the prototype sildenafil-like PDE5 inhibitors that surfaced in all-natural male-enhancement supplements. Built to mimic sildenafil's blood-flow-boosting mechanism, it delivers erectile-support effects without the branding of a prescription drug, which made it one of the earliest and most widely copied research analogues in the space. It is sought out in gray-market circles precisely for reproducing a pharmaceutical effect in an unregulated form.

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Cardiovascular

Riociguat

Riociguat is an oral medication in a class of drugs called soluble guanylate cyclase stimulators, and it was the first agent of this type to reach the market. It is used to treat two forms of pulmonary hypertension: chronic thromboembolic pulmonary hypertension that persists after or cannot be corrected by surgery, and pulmonary arterial hypertension. Developed by Bayer, it is sold under the brand name Adempas.

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Blend

Sildenafil + Tadalafil

Sildenafil plus tadalafil is the combined use of two phosphodiesterase type 5 (PDE5) inhibitors for erectile dysfunction, typically a longer-acting daily tadalafil together with on-demand sildenafil. The strategy is generally reserved for men who respond poorly to a single PDE5 inhibitor. Because both drugs share the same basic mechanism, combining them mainly extends coverage rather than adding a new mode of action.

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Cardiovascular

Udenafil

Udenafil is a phosphodiesterase type 5 (PDE5) inhibitor, a class of drug used mainly to treat erectile dysfunction. Marketed under the brand name Zydena, it was developed by the South Korean company Dong-A Pharmaceutical and is approved in Korea and several other countries, though not in the United States. It is distinguished by a relatively quick onset together with a long duration of action, which allows both on-demand and once-daily use [1].

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Respiratory

Dyphylline

Dyphylline is a xanthine-derivative bronchodilator that relaxes airway smooth muscle through nonselective phosphodiesterase inhibition and weak adenosine-receptor antagonism. Chemically 7-(2,3-dihydroxypropyl)-1,3-dimethylxanthine, it is a distinct synthetic methylxanthine rather than a theophylline salt, and unlike theophylline it is not metabolized to theophylline in the body but is instead cleared largely unchanged by the kidneys. Marketed for decades under names such as Dilor and Lufyllin (often combined with the expectorant guaifenesin), it is an FDA-approved agent used for the symptomatic relief of bronchospasm in asthma, chronic bronchitis, and chronic obstructive pulmonary disease. Compared with theophylline it is a somewhat weaker bronchodilator on a milligram basis but carries a wider tolerability margin, a shorter half-life, and far fewer drug and smoking interactions because it bypasses hepatic CYP1A2 metabolism. More recent laboratory work has explored repurposing dyphylline as a coronavirus main-protease inhibitor and as a cAMP-raising activator of dormant ovarian follicles.

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Stimulant

IBMX

IBMX (3-isobutyl-1-methylxanthine) is a synthetic methylxanthine and nonselective phosphodiesterase inhibitor that also antagonizes adenosine receptors, widely used as a research reagent to raise intracellular cAMP and cGMP. It inhibits most cyclic-nucleotide phosphodiesterase families in the low-micromolar range while comparatively sparing PDE8 and PDE9, and it is a standard component of cell-differentiation cocktails for adipocytes and melanocytes as well as a common positive control in phosphodiesterase and adenosine-receptor pharmacology assays.

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Neuroprotection

Ibudilast

Ibudilast (MN-166, Ketas) is a brain-penetrant, multi-target neuroimmune modulator that stands apart from the pure PDE4 crowd. It inhibits several phosphodiesterases (PDE3/4/10/11) while also blocking macrophage migration inhibitory factor (MIF) and toll-like receptor 4 (TLR4), quieting overactive glia and shifting cytokines toward repair. Marketed for decades in Japan for asthma and post-stroke dizziness, it has advanced internationally as MN-166 through progressive MS, ALS and addiction trials.

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Nootropic

TAK-063

Balipodect (TAK-063) is a selective phosphodiesterase 10A (PDE10A) inhibitor developed by Takeda as a potential antipsychotic for schizophrenia. It has completed phase 2 proof-of-concept testing and, as of 2026, was acquired by Axsome Therapeutics for further development.

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