Many medications stimulate appetite and lead to weight gain. Patients complain of a ravenous appetite and the inability to feel full. Weight gains of 40 to 60 lb (15-30 kg) in a few months are not uncommon.
Appetite and feeding are regulated by a complex of neurotransmitters, neuromodulators, cytokines and hormones interacting with the hypothalamus, including the leptin and the tumor necrosis factor system. The pharmacologic mechanisms underlying weight gain are presently poorly understood: maybe the different activities at some receptor systems may induce it, but also genetic predisposition. Understanding of the metabolic consequences of psychotropic drugs (weight gain, diabetes, dyslipidemia) is essential: the insulin-like effect of lithium is known. Treatment with antipsychotic medications increases the risk of impaired glucose tolerance and diabetes mellitus.
A list of drugs that can increase appetite:
Psychotropics – Alprazolam (Xanax), Benzodiazepine antianxiety agents, Chlordiazepoxide (Librium).
Antipsychotics – Haloperidol (Haldol), Perphenazine (Trilafon), Thiothixene (Navane), Thioridazine HCl (Mellaril), Clozapine (Clozaril), Olanzapine (Zyprexa), Quetiapine Fumarate (Seroquel), Risperidone (Risperdal).
Antidepressants – Amitriptyline HCl (Elavil), Clomipramine HCl (Anafranil), Doxepin HCl (Sinequan), Imipramine HCl (Tofranil), Isocarboxazide (Marplan), Mirtazapine (Remeron), Paroxetine (Paxil), Phenelzine sulfate (Nardil), Selegiline (Eldepryl), Tranylcypromine sulfate (Parnate).
Anticonvulsants – Divalproex/valproic acid (Depakote/Depakene), Gabapentin (Neurontin).
Hormones – Corticosteroids (cortisone, methylprednisolone, prednisolone), Human growth hormone/somatropin (Serostim), Medroxyprogesterone acetate (Provera, Depo-Provera), Megestrol acetate (Megace), Oxandrolone (Oxandrin), Oxymetholone (Anadrol-50), Testosterone (Androderm, Testoderm).
Miscellaneous - Cyproheptadine (Periactin), Dronabinol (Marinol).
Patients beginning maintenance therapy should be informed of drugs side effects, and teached how to manage weight: