Can switching from Finasteride to Dutasteride cause a second shed?

What type of hair loss are you experiencing? Finasteride and dutasteride are indicated for male pattern baldness. In male-pattern baldness, hair falls out in clear, recognizable patterns. Hair loss due to thyroid conditions results in a diffuse thinning across your entire scalp.
Both dutasteride and finasteride are 5 alpha-reductase inhibitors inhibiting the conversion of testosterone to dihydrotestosterone (DHT). DHT is the more potent version of testosterone and accounts for many symptoms including prostatic enlargement and hair loss.
Finasteride blocks type II 5AR, and dutasteride blocks type I and II 5 AR. Type III is quite minute and not considered germane to the efficacy of the either drug.
Finasteride is 70 % effective in blocking 5AR while dutasteride is 98 +% effective.
These medications are effective for male pattern baldness. If you are experiencing hair loss on them, you need to have an evaluation. The thyroid gland is particularly involved in overall hair thinning on the scalp.
Othe areas to explore are nutritional adequacy and some medications have hair loss as a side effect.Medications include:
Antibiotics: gentamicin, chloramphenicolAnticoagulants: warfarin, heparinAntidepressants: fluoxetine, desipramine, lithiumAnticonvulsants: valproic acid, phenytoin, carbamazepineCardiovascular meds: ACE inhibitors, beta-blockersChemotherapy drugs: doxorubicin, vincristine, etoposideEndocrine drugs: bromocriptine, clomiphene, danazolGout medications: colchicine, allopurinolLipid-lowering drugs: gemfibrozil, fenofibrate, cholestyramine, clofibrateNSAIDS: ibuprofen, indomethacin, naproxenReflux/ulcer medications: cimetidine, ranitidine, famotidineAntithyroid drugs: iodine, PTURetinoids: vitamin A overdose, isotretinoin
I hope this helps!

It is possible that a patient who does not respond well to finasteride gets a shed with dutasteride. However, one also needs to keep in mind the possibility that another diagnosis is present. It nay or may not simply be the dutasteride. Be sure to see a hair loss expert for full evaluation.