Pheniramine (trade name Avil among others) is an

antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provide ...

with

anticholinergic Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system. These agents inhibit the parasympathetic nervous sys ...

properties used to treat

allergic Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic der ...

conditions such as

hay fever Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, i ...

urticaria Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-last ...

. It has relatively strong sedative effects, and may sometimes be used off-label as an over-the-counter sleeping pill in a similar manner to other sedating antihistamines such as

diphenhydramine Diphenhydramine (DPH) is an antihistamine and sedative mainly used to treat allergies, insomnia, and symptoms of the common cold. It is also less commonly used for tremor in parkinsonism, and nausea. It is taken by mouth, injected into ...

. Pheniramine is also commonly found in eyedrops used for the treatment of

allergic conjunctivitis Allergic conjunctivitis (AC) is inflammation of the conjunctiva (the membrane covering the white part of the eye) due to allergy. Although allergens differ among patients, the most common cause is hay fever. Symptoms consist of redness (mainly due ...

. It was patented in 1948. Pheniramine is generally sold in combination with other medications, rather than as a stand-alone drug, although some formulations are available containing pheniramine by itself.

Side effects

Pheniramine may cause drowsiness or

Tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ( ...

, and over-dosage may lead to sleep disorders. Overdose may lead to

seizures An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with lo ...

, especially in combination with alcohol. People combining with

cortisol Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in many animals, mainly by the '' zona fasciculata'' of the adrenal cortex in the adrenal g ...

in the long term should avoid pheniramine as it may decrease levels of adrenaline (epinephrine) which may lead to loss of consciousness. Pheniramine is a

deliriant Deliriants are a subclass of hallucinogen. The term was coined in the early 1980s to distinguish these drugs from psychedelics and dissociatives such as LSD and ketamine, respectively, due to their primary effect of causing delirium, as oppose ...

(hallucinogen) in toxic doses. Recreational use of Coricidin for the

dissociative Dissociatives, colloquially dissos, are a subclass of hallucinogens which distort perception of sight and sound and produce feelings of detachment – dissociation – from the environment and/or self. Although many kinds of drugs are capable of ...

(hallucinogenic) effect of its dextromethorphan is hazardous because it also contains

chlorpheniramine Chlorphenamine (CP, CPM), also known as chlorpheniramine, is an antihistamine used to treat the symptoms of allergic conditions such as allergic rhinitis (hay fever). It is taken by mouth. The medication takes effect within two hours and lasts ...

Chemical relatives

Halogenation In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers ...

of pheniramine increases its potency 20-fold. Halogenated derivatives of pheniramine include

chlorphenamine Chlorphenamine (CP, CPM), also known as chlorpheniramine, is an antihistamine used to treat the symptoms of allergic conditions such as allergic rhinitis (hay fever). It is taken by mouth. The medication takes effect within two hours and lasts ...

brompheniramine Brompheniramine, sold under the brand name Dimetapp among others, is a first-generation antihistamine drug of the propylamine (alkylamine) class. It is indicated for the treatment of the symptoms of the common cold and allergic rhinitis, such a ...

, dexchlorpheniramine,

dexbrompheniramine Dexbrompheniramine is an antihistamine with anticholinergic properties used to treat allergic conditions such as hay fever or urticaria. It is the pharmacologically active dextrorotatory isomer of brompheniramine. It was formerly marketed in comb ...

, and zimelidine. Two other halogenated derivatives, fluorpheniramine and iodopheniramine, are currently in use for research on combination therapies for malaria and some cancers. Other analogs include

, and doxylamine.

Stereoisomerism

Pheniramine contains a stereocenter and can exists as either of two

enantiomer In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical anti ...

s. The pharmaceutical drug is a

racemate In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...

, an equal mixture of the (''R'')- and (''S'')-forms.

References

External links

* *
Leaflet on Avil
by The

Royal Australian College of General Practitioners The Royal Australian College of General Practitioners (RACGP) is the professional body for general practitioners (GPs) in Australia. The RACGP is responsible for maintaining standards for quality clinical practice, education and training, and re ...

{{Navboxes , title =

Pharmacodynamics Pharmacodynamics (PD) is the study of the biochemical and physiologic effects of drugs (especially pharmaceutical drugs). The effects can include those manifested within animals (including humans), microorganisms, or combinations of organisms ...

, titlestyle = background:#ccccff , list1 = {{Histamine receptor modulators {{Monoamine reuptake inhibitors {{Muscarinic acetylcholine receptor modulators Dimethylamino compounds Deliriants H1 receptor antagonists Muscarinic antagonists 2-Pyridyl compounds Sanofi Serotonin reuptake inhibitors

Side effects

Chemical relatives

Stereoisomerism

See also

References

External links