Megaphen - General Information
A phenothiazine with actions similar to chlorpromazine but with less antipsychotic activity. It is primarily used in short-term treatment of disturbed behavior and as an antiemetic. [PubChem]
Pharmacology of Megaphen
Megaphen belongs to a group of medications known as the phenothiazine antipsychotics. It acts by blocking a variety of receptors in the brain, particularly dopamine receptors. Dopamine is involved in transmitting signals between brain cells. When there is an excess amount of dopamine in the brain it causes over-stimulation of dopamine receptors. These receptors normally act to modify behaviour and over-stimulation may result in psychotic illness. Megaphen hydrochloride blocks these receptors and stops them becoming over-stimulated, thereby helping to control psychotic illness. Megaphen has weak extrapyramidal and autonomic side effects which lead to its use in the elderly, for restless or psychotic patients. Its anti-psychotic effect is also weaker and it is not useful in general psychiatry.
Additional information about Megaphen
Megaphen Indication: Used as an adjunct for short term treatment of moderate and severe psychomotor agitation. Also used to treat agitation or restlessness in the elderly.
Mechanism Of Action: Megaphen is an antagonist at types 1, 2, and 4 dopamine receptors, 5-HT receptor types 2A and 2C, muscarinic receptors 1 through 5, alpha(1)-receptors, and histamine H1-receptors. Megaphen's antipsychotic effect is due to antagonism at dopamine and serotonin type 2 receptors, with greater activity at serotonin 5-HT2 receptors than at dopamine type-2 receptors. This may explain the lack of extrapyramidal effects. Megaphen does not appear to block dopamine within the tubero-infundibular tract, explaining the lower incidence of hyperprolactinemia than with typical antipsychotic agents or risperidone. Antagonism at muscarinic receptors, H1-receptors, and alpha(1)-receptors also occurs with promazine.
Drug Interactions: Not Available
Food Interactions: Not Available
Generic Name: Promazine
Synonyms: Chlorpromazine Hcl; CPZ; Phenothiazine; Promazine Hcl; Promazina; Promazin
Drug Category: Antipsychotics; Antiemetics; Neuroleptics; Phenothiazines
Drug Type: Small Molecule; Approved
Other Brand Names containing Promazine: AB; Aminazin; Aminazine; Ampazine; Ampliactil; Amplictil; Berophen; Chlor-Promanyl; Chlordelazin; Chlorderazin; Chlorpromados; Chlorpromazine Hcl Intensol; Chlropromados; Contomin; Elmarin; Esmind; Esparin; Fenactil; Fenaktyl; Fraction; Largactil; Largactilothiazine; Largactyl; Liranol; Megaphen; Neo-Hibernex; Novomazina; Phenactyl; Prazin; Prazine; Proma; Promactil; Promapar; Promazil; Promwill; Propaphenin; Protactyl; Prozil; Psychozine; Romtiazin; Sanopron; Sinophenin; Sonazine; Sparine; Thorazine; Torazina; Verophen; Vesprin; Wintermin;
Absorption: Absorption may be erratic and peak plasma concentrations show large interindividual differences.
Toxicity (Overdose): Side effects include: extrapyramidal symptoms, drowsiness, weight gain, dry mouth, constipation, endocrine effects (such as gynaecomastia and menstrual disturbance), sensitivity to sunlight and haemolytic anaemia.
Protein Binding: 94%
Biotransformation: Hepatic, primarily to N-desmethylpromazine and promazine sulfoxide.
Half Life: Not Available
Dosage Forms of Megaphen: Liquid Intramuscular
Chemical IUPAC Name: N,N-dimethyl-3-phenothiazin-10-ylpropan-1-amine
Chemical Formula: C17H20N2S
Promazine on Wikipedia: https://en.wikipedia.org/wiki/Promazine
Organisms Affected: Humans and other mammals