Drug General Information (ID: DDIIWNCD37)
  Drug Name Timolol (ophthalmic) Drug Info Givosiran Drug Info
  Drug Type Small molecule Small interfering RNA
  Therapeutic Class Antiarrhythmic Agents Metabolic Agents
  Structure

 Mechanism of Timolol (ophthalmic)-Givosiran Interaction (Severity Level: Moderate)
     CYP450 enzyme inhibition Click to Show/Hide Mechanism Graph
Could Not Find 2D Structure
      Drug Name Timolol (ophthalmic) Givosiran
      Mechanism CYP450 2D6 substrate CYP450 2D6 inhibitor
      Key Mechanism Factor 1
Factor Name Cytochrome P450 2D6
×
Structure Sequence
MGLEALVPLAVIVAIFLLLVDLMHRRQRWAARYPPGPLPLPGLGNLLHVDFQNTPYCFDQLRRRFGDVFSLQLAWTPVVVLNGLAAVREALVTHGEDTADRPPVPITQILGFGPRSQGVFLARYGPAWREQRRFSVSTLRNLGLGKKSLEQWVTEEAACLCAAFANHSGRPFRPNGLLDKAVSNVIASLTCGRRFEYDDPRFLRLLDLAQEGLKEESGFLREVLNAVPVLLHIPALAGKVLRFQKAFLTQLDELLTEHRMTWDPAQPPRDLTEAFLAEMEKAKGNPESSFNDENLRIVVADLFSAGMVTTSTTLAWGLLLMILHPDVQRRVQQEIDDVIGQVRRPEMGDQAHMPYTTAVIHEVQRFGDIVPLGVTHMTSRDIEVQGFRIPKGTTLITNLSSVLKDEAVWEKPFRFHPEHFLDAQGHFVKPEAFLPFSAGRRACLGEPLARMELFLFFTSLLQHFSFSVPTGQPRPSHHGVFAFLVSPSPYELCAVPR
Gene Name CYP2D6
Uniprot ID CP2D6_HUMAN
KEGG Pathway hsa:1565
Protein Family Cytochrome P450 family
Protein Function
A cytochrome P450 monooxygenase involved in the metabolism of fatty acids, steroids and retinoids (PubMed:18698000, PubMed:19965576, PubMed:20972997, PubMed:21289075, PubMed:21576599). Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (NADPH--hemoprotein reductase) (PubMed:18698000, PubMed:19965576, PubMed:20972997, PubMed:21289075, PubMed:21576599). Catalyzes the epoxidation of double bonds of polyunsaturated fatty acids (PUFA) (PubMed:19965576, PubMed:20972997). Metabolizes endocannabinoid arachidonoylethanolamide (anandamide) to 20-hydroxyeicosatetraenoic acid ethanolamide (20-HETE-EA) and 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acid ethanolamides (EpETrE-EAs), potentially modulating endocannabinoid system signaling (PubMed:18698000, PubMed:21289075). Catalyzes the hydroxylation of carbon-hydrogen bonds. Metabolizes cholesterol toward 25-hydroxycholesterol, a physiological regulator of cellular cholesterol homeostasis (PubMed:21576599). Catalyzes the oxidative transformations of all-trans retinol to all-trans retinal, a precursor for the active form all-trans-retinoic acid (PubMed:10681376). Also involved in the oxidative metabolism of drugs such as antiarrhythmics, adrenoceptor antagonists, and tricyclic antidepressants.
    Click to Show/Hide
      Mechanism Description
  • Decreased metabolism of Timolol (ophthalmic) caused by Givosiran mediated inhibition of CYP450 enzyme

Recommended Action
      Management Patients should be monitored for systemic beta-adrenergic blocking effects of topical timolol during coadministration with CYP450 2D6 inhibitors such as cimetidine, quinidine, and certain selective serotonin reuptake inhibitors. Particular caution is warranted in elderly patients, since they are generally more susceptible to adverse effects of topically administered beta blockers.

References
1 Edeki TI, He HB, Wood AJJ "Pharmacogenetic explanation for excessive beta-blockade following timolol eye drops: potential for oral-ophthalmic drug interaction." JAMA 274 (1995): 1611-3. [PMID: 7474246]
2 Fraunfelder FT, Fraunfelder FW Randall JA "Drug-Induced Ocular Side Effects 5th" Boston, MA: Butterworth-Heinemann (2001):.
3 Lewis RV, Lennard MS, Jackson PR, Tucker GT, Ramsay LE, Woods HF "Timolol and atenolol: relationships between oxidation phenotype, pharmacokinetics and pharmacodynamics." Br J Clin Pharmacol 19 (1985): 329-33. [PMID: 2859048]