Absorption is the process of drug penetration from the site of application or injection into the blood, and from the blood into tissues through various cell membranes. Seeing as in psychiatry, most prescribed drugs are to be taken orally, a thorough understanding of their absorption interactions is essential. For example, Wasik et al. (2019) explain that “drug and food interactions can modify the pharmacokinetic (e.g. absorption, metabolism) and/or pharmacodynamic properties of drugs” (p. 51).
In case of absorption interactions of psychiatric drugs, both the speed and completeness of absorption are of great importance. Knowledge of how to change the rate of absorption can be crucial when carrying out therapy aimed at achieving a quick and pronounced effect. Additionally, the completeness of absorption is always important, because the future concentration of active substances in the blood depends on this indicator. This knowledge also proves to be invaluable when it comes to the drug intoxication, where the life of a patient depends on the health care worker’s experience.
For example, antidepressant intoxication and interactions with other drugs are known to be extremely difficult to manage. In some cases, they can even lead to death if not addressed properly. Spina et al. (2019) state that “clinicians need to pay attention to all drugs taken by their patients since they may further increase the risk of drug interactions between oral anticoagulants and antidepressants” (p. 43).
Among the classes of antidepressants, tricyclic antidepressants and monoamine oxidase inhibitors (MAOI) pose the greatest danger of intoxication due to the rapid absorption of the drugs from the gastrointestinal tract. However, Stahl (2014) claims that “with knowledge of MAOI therapeutic, dietary, and drug-interaction mechanisms, clinicians may be able to revive these agents as therapeutic tools in the fight against treatment-resistant depression and anxiety” (p. 342). Thus, it is important to understand how these antidepressant interact with the organism on the absorption levels, and try and predict the effect from the prescribed dose.
References
Spina, E., Barbieri, M. A., Cicala, G., Bruno, A., & de Leon, J. (2019). Clinically relevant drug interactions between newer antidepressants and oral anticoagulants. Expert Opinion on Drug Metabolism & Toxicology, 16(1), 31–44. Web.
Stahl, S. M. (2014). Stahl’s essential psychopharmacology. Cambridge University Press.
Wasik, A., Krupa, A., & Siwek, M. (2019). Interactions of antidepressants, mood-stabilisers and antipsychotics with food. Pharmacotherapy in Psychiatry and Neurology, 35(1), 51–74. Web.