McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 2 1 Antidepressant agents

TABLE 21.5

DRUGS IN FOCUS Other antidepressants

Drug name

Dosage/route

Usual indications

agomelatine (Valdoxan)

25 mg PO at night

Treatment of major depression in adults, including relapse prevention Treatment of depression in adults, smoking cessation Treatment of major depressive disorder in adults Treatment of major depression in adults

bupropion (Prexaton)

150 mg PO b.d. in sustained-release form or 150–300 mg/day as a single dose of extended-release form 50 mg/day PO with or without food; range 50–200 mg/day 30 mg/day in three divided doses, maximum 120 mg/day 15 mg/day PO, may be increased to a maximum of 45 mg/day; reduce dose in elderly people and those with renal or hepatic dysfunction 300–600 mg PO daily in two divided doses

desvenlafaxine (Pristiq)

mianserin (Lumin, Tolvon)

mirtazapine (Avanza)

Treatment of depression in adults

moclobemide (Amira) reboxetine (Edronax) selegiline (Eldepryl) venlafaxine (Efexor XR)

Treatment of major depression in adults Treatment of major depression in adults Treatment of major depressive disorder Treatment and prevention of depression in generalised anxiety disorder; social anxiety disorder; decreases addictive behaviour

4 mg PO b.d., up to 10 mg/day

5 mg PO b.d.

75 mg/day PO in divided doses, to 375 mg/day; 75 mg/day PO sustained-release formulation to a maximum 225 mg/day; reduce dose with hepatic and renal impairment

women. As with other SSRIs, it should be used in pregnancy only if the benefit clearly outweighs the risk. It is taken orally, once a day. • Moclobemide ( Amira, Aurorix ) is a MAO type A inhibitor used for the treatment of major depressive disorder. The drug is metabolised in the liver and excreted through urine. The drug does cross the placenta and enters breast milk, so it should only be used during pregnancy and breastfeeding if the benefit outweighs the potential risk to the neonate. This drug is associated with CNS effects, as well as GI effects including nausea, constipation, diarrhoea and dry mouth. • Mianserin ( Lumin, Tolvon ) is a tetracyclic antidepressant, related to other TCAs, used to manage major depression and has effective sedative properties. Mianserin blocks alpha 2 adrenoceptors blocking reuptake of noradrenaline, and interacts with serotonin receptors. Mianserin has a half-life of 21 to 61 hours. It is rapidly absorbed and excreted in the urine and faeces. Little is known about its effects in pregnancy and breastfeeding, and it should be used during those times only if the benefit to the mother clearly outweighs the potential risk to the neonate. • Mirtazapine ( Avanza ) is rapidly absorbed from the GI tract, extensively metabolised in the liver and excreted in the urine. Mirtazapine has a half-life of 20 to 40 hours. How its many anticholinergic effects relate to its antidepressive effects is not known. Little is known about its effects in pregnancy and breastfeeding, and it should be used during those times only if the benefit to the mother clearly outweighs the potential risk to the neonate.

• Reboxetine ( Edronax ) is a newer noradrenaline reuptake inhibitor used for managing major depression. It is rapidly absorbed with a half-life of 12 hours. Reboxetine is metabolised in the liver and excreted in the urine. Little is known about its effects in pregnancy and breastfeeding, and it should be used during those times only if the benefit to the mother clearly outweighs the potential risk to the neonate. • Selegiline ( Eldepryl ) is a MAO type B inhibitor that has been used for many years in the treatment of Parkinson’s disease and for the treatment of major depressive disorder. The drug is metabolised in the liver and excreted through urine. A substantial increase in selegiline bioavailability (up to threefold) occurs when selegiline is administered with food high in fat. The drug does cross the placenta and enters breast milk, so it should only be used during pregnancy and breastfeeding if the benefit outweighs the potential risk to the neonate. This drug is associated with CNS effects, as well as GI effects including nausea, vomiting, dry mouth and abdominal pain. • Venlafaxine ( Efexor ) mildly blocks the reuptake of noradrenaline, 5HT and dopamine and has fewer adverse CNS effects than other antidepressants. Its popularity has increased with the introduction of an extended-release form that does away with the multiple daily doses that are required with the regular form. Venlafaxine is readily absorbed from the GI tract, extensively metabolised in the liver and excreted in urine. Adequate studies have not been done in pregnancy and breastfeeding, and it should be used during those times only if the benefit to the mother clearly outweighs the potential risk to the neonate.