Table 2.
Pharmacokinetic and Pharmacodynamics properties of CPM and TRD.
| Chlorpheniramine (CPM) | Trazodone (TRD) | |
|---|---|---|
| Mechanism of action | Competitive histamine H1 receptor antagonist | Serotonin type 2 (5-HT2) receptors, alpha1 (α1) adrenergic receptors antagonist and serotonin reuptake transporter inhibitor |
| Pro-drug | Chlorpheniramine Maleate | No |
| Dosing frequency | 4 mg tablet, two times a day | 50 to 150 mg per day |
| Bioavailability (%) | 25 to 44 (Huang et al., 1982) | 65 (Settimo and Taylor, 2018) |
| Tmax | 2.08 h (Kotzan et al., 1982) | 1.4 to 2.3 h |
| Half-life | 13.9 to 43.3 h with multiple doses (Kirkegaard et al., 1983) | 7.8 to 14.6 h |
| Metabolism | Mono- and didesmethyl-chlorpheniramine | m-chlorophenylpiperazine |
| Mode of excretion | 20–26.5% of unchanged CPM excreted renally (Rumore, 1984) | 70 to 75% excreted renally 21% excreted by the fecal route |
NR, Not reported; Tmax, Time to maximum plasma concentration.