Antidepressants

Antidepressants  - Tricyclic antidepressants. Monoamine oxidase inhibitors (MAOI).
Tetracyclic antidepressants.

Dangers - Interaction with narcotics and catecholamines.

Precautions  - Narcotics - Cautious use of pethidine, morphine, omnopon etc. Catecholamines - Avoid adrenaline, nor-adrenaline; use felypressin.

These may be divided into three categories: 

• Direct stimulants.
• Monoamine oxidase inhibitors.
• Tricyclic antidepressants.

All three categories may cause adverse drug reactions with other drugs.

Reactions to the monoamine oxidase (MAO) inhibitor drugs include hypertensive episodes accompanied by severe headache. Such episodes can be precipitated by sympathomimetic drugs. Administration of sympathomimetic drugs or ephedrine to patients taking MAO inhibitors, or who have taken the within the preceding month, is contra-indicated.

As the widely used tricyclic see these details antidepressant drugs also potentiate the pressor effects of adrenaline and nor-adrenaline, the administration of sympathomimetic drugs in this group should also be avoided.

Standard doses of narcotics, e.g. morphine, pethidine and Omnopon, when administered to patients on MAO inhibitors, may provoke hypertension and an accentuation of their normal depressive effect on respiration: this may result in severe respiratory depression and loss of consciousness.

Felypressin (Octapressin) is the vasoconstrictor of choice for patients taking antidepressants.