Mequitazine (trade name Primalan) is an antihistamine and anticholinergic of the phenothiazine chemical class. It is used to treat allergies and rhinitis.

Severe liver disease; premature infants or full-term neonates .

Pregnancy, lactation; severe CardioVascular disorders; asthma; angle-closure glaucoma, urinary retention, prostatic hyperplasia, pyloroduodenal obstruction; renal and hepatic impairment; elderly, children; epilepsy. May impair ability to drive or operate machinery.

CNS depression including slight drowsiness to deep sleep, lassitude, dizziness, incoordination. Headache, psychomotor impairment and antimuscarinic effects. Rarely, rashes and hypersensitivity reactions, blood disorders, convulsions, sweating, myalgia, paraesthesias, extrapyramidal effects, tremor, confusion, sleep and GI disturbances, tinnitus, hypotension, hair loss. Photosensitivity, jaundice.

Enhanced effects of CNS depressants e.g. alcohol, barbiturates, hypnotics, opioid analgesics, anxiolytic sedatives and antipsychotics. Can mask signs of ototoxicity caused by aminoglycosides. QT prolongation reported with spiramycin.

• Phenothiazine