Subcutaneously in Latin

Prescription writing for subcutaneous administration

When writing prescriptions in Latin, the name of the drug itself and its form are indicated in Latin, but the patient instructions, including the route of administration (e.g., subcutaneously), are written in Russian in the signature section (Signatura, designated by the abbreviation S.).

Let us consider examples of prescribing drugs from the group of direct and indirect acting alpha- and beta-adrenomimetics:

1. Prescription for adrenaline:

Rp.: Sol. Adrenalini hydrochloridi 0.1% — 1 ml D.t.d. N. 10 in ampullis S. 0.3–0.5 ml subcutaneously in anaphylactic shock.

1. Prescription for ephedrine:

Rp.: Sol. Ephedrini hydrochloridi 5% — 1 ml D.t.d. N. 10 in ampullis S. 1 ml subcutaneously or intramuscularly.

In both cases, we see that the active substance is indicated in the genitive case in Latin, while the method of administration is in Russian.

Dependence of the effect on the route of administration: Epinephrine

Epinephrine (Adrenaline) is available as a 0.1% epinephrine hydrochloride solution. An important rule when working with this solution is that it must strictly never be heated.

The pharmacological effect of epinephrine strictly depends on the chosen route of administration. Subcutaneous administration is used to achieve a bronchodilator effect. In this case, an excessive pressor effect (a sharp increase in blood pressure) is avoided. Intravenous or intramuscular administration is used in anaphylactic shock when the patient critically needs a pronounced pressor effect.

Special attention should be paid to the interaction of epinephrine with α-adrenoblockers (e.g., phentolamine). Against the background of their action, the phenomenon of «reversal» of the pressor effect occurs: administration of adrenaline causes a decrease rather than an increase in blood pressure. The mechanism of this phenomenon is that the blockade of α-adrenoceptors, which are responsible for vasoconstriction, causes adrenaline to act exclusively on β₂-adrenoceptors, whose function is vasodilation.

Features of norepinephrine use

Norepinephrine (Noradrenaline) is used in medical practice as a salt — norepinephrine hydrotartrate. It is used as a 0.02% solution in a 1:50,000 ratio.

Unlike drugs that can be safely administered subcutaneously, norepinephrine requires extreme caution during intravenous administration. This is due to the high risk of tissue necrosis in case of extravasation (the drug entering surrounding tissues outside the vein).

Pharmacological profile of ephedrine

Ephedrine is an alkaloid derived from the ephedra plant (Ephedra L.). In its chemical structure, it is very close to adrenaline. The main difference is the absence of hydroxyl groups in the aromatic ring (phenyl nucleus).

There are different forms of this substance. Plant-derived ephedrine is the levorotatory isomer. Synthetic ephedrine is a racemic mixture. In medicine, the drug is used as a salt — ephedrine hydrochloride.

When using it, two critically important factors must be considered:

• Tachyphylaxis: The efficacy of ephedrine directly depends on noradrenaline stores in presynaptic terminals. For this reason, frequent administrations of the drug lead to rapid tolerance, and its effect diminishes.
• Risk of dependence: The drug has a pronounced psychostimulant effect and is capable of causing drug dependence. Because of this, ephedrine is not used independently in general practice.

Class and exam questions

What else to study on this topic

• Mechanism of action of ephedrine on presynaptic terminals
• Pharmacodynamics of α- and β-adrenomimetics: Norepinephrine (Noradrenaline)
• Mechanisms of action of centrally acting antihypertensives
• Chemical structure of adrenomimetics: the role of hydroxyl groups in the phenyl nucleus
• Differences between levorotatory isomers and racemic mixtures in pharmacology

Other topics in the "Additional Topics" section

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